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mr.prick
August 30th, 2008, 11:35 AM
my car will not start, it keeps cranking and seems to not be getting any spark.
it will start if i floor the gas peddle but it sputters and reeks of gas.:angel_innocent:
FP is fine (60PSI) while cranking, IBPW averages 30.6ms,
fuses are good, relays are clicking and battery voltage drops to 9volts:shock: with a new battery.

i was getting P1626 but it has not come back.
i am getting U1016 consistently.
i can scan/log and upload/download my RR but i can not retrieve the calibration/VIN with the tune.exe,
it says flashscan is not connected.
i thought it might be VATS because of the P1626 but, i logged GM.STATE02
and VATS Fuel Disable is Inactive.
i now suspect some kind of ground or connector wire has failed. (where?)
any suggestion is appreciated.

3814

3815

joecar
August 30th, 2008, 12:12 PM
My service manual lumps these all together:


DTC U1001-U1254 : Lost Communications With XXX

F-body has only 4 modules... you have a loose ground cable or something.

mr.prick
August 30th, 2008, 12:40 PM
My service manual lumps these all together:



F-body has only 4 modules... you have a loose ground cable or something.

when i check all modules, flashscan sees them.
i know where the BCM and ASR is,
where are the other 2 modules and the PCM ground?
this started after i changed fuel injectors, is there a ground in the injector/coils harness?

joecar
August 30th, 2008, 03:13 PM
See post #33 for grounds: showthread.php?t=1913 (http://forum.efilive.com/showthread.php?t=1913)

Modules:
- PCM (id $10) -> in RHS of engine bay, near hinge;
- EBCM/ABS/TCS/ASR (id $28) -> in LHS of engine bay, near fuse panels;
- SDM/airbag (id $58) -> under console, on trans. tunnel, between gear lever and brake lever;
- IPC (id $60) -> integral with instrument panel;

In all cases, if you poke around under the dash/console, make sure battery is disconnected to avoid airbag firing...!!

joecar
August 30th, 2008, 03:21 PM
SIR Service Precautions

Caution

When you are performing service on or near the SIR components or the SIR wiring, you must disable the SIR system. Refer to Disabling the SIR System. Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.


The inflatable restraint sensing and diagnostic module (SDM) maintains a reserved energy supply. The reserved energy supply provides deployment power for the air bags. Deployment power is available for as much as 1 minute after disconnecting the vehicle power. Disabling the SIR system prevents deployment of the air bags from the reserved energy supply.

mr.prick
August 30th, 2008, 04:22 PM
thanks joecar.:grin:
i have already taken the steering wheel off and checked the ignition wires.
i put a resistor between 1073 and 1074 at the BCM but,
LOL it was the wrong one so the car would not turn over at all.
i am thinking that the DTC`s are being set because of the
voltage drop while cranking.
i know you suggested a bad ground but,
could the alternator cause this as well?

hquick
August 30th, 2008, 06:46 PM
Found some info on U codes.

Most TACM communication problems can be traced to a bad (or even weak) battery. The second most common cause is bad grounds.

hquick
August 30th, 2008, 07:03 PM
And more:

Well the only control from the pcm to the alternator is if your vehicle is equipped with a generator control module which started in 2005 and up otherwise the alternator works just liek a alternator suppossed to here is a description on that GCM
The generator is a serviceable component. If there is a diagnosed failure of the generator it must be replaced as an assembly. The engine drive belt drives the generator. When the rotor is spun it induces an alternating current (AC) into the stator windings. The AC voltage is then sent through a series of diodes for rectification. The rectified voltage has been converted into a direct current (DC) for use by the vehicles electrical system to maintain electrical loads and the battery charge. The voltage regulator integral to the generator controls the output of the generator. It is not serviceable. The voltage regulator controls the amount of current provided to the rotor. If the generator has field control circuit failure, the generator defaults to an output voltage of 13.8 volts.

Generator Battery Control Module
The generator battery control module is a class 2 device. It communicates with the powertrain control module (PCM), instrument panel cluster and the body control module for electrical power management (EPM) operation. It is a serviceable component that is connected to the negative battery cable at the battery. It directly controls the generator field control circuit, charge indicator control, input to the generator. It continuously monitors the generator field duty cycle signal circuit and the battery voltage. If the generator battery control module loses communication with the PCM, the default voltage will be set to 13.8 volts and the module will set U1016. If the generator battery control module loses communication with the body control module (BCM), the module will set U1064.

Powertrain Control Module (PCM)
The PCM provides information over the class 2 serial data circuit to the generator battery control module. The generator battery control module monitors the following data parameters provided by the PCM:

• Intake air temperature

• Fuel grams per second

• Throttle position

• Engine cooling fan speed

• Engine coolant temperature

• Exterior Environment - Outside Air Temperature

The generator battery control module uses these data parameters for different charging system modes depending on the required voltage needed.

Charge Mode
The generator battery control module will enter Charge Mode when at least one of the following conditions is met:

• The electric cooling fans are on high speed.

• The rear defogger is ON.

• The battery state of charge is less than 80 percent.

• The battery current is not between -8 and 15 amps.

• The estimated ambient air temperature is less than 0C.

• DTC B1516 is set.

Once one of these conditions are met the generator battery control module will set the targeted generator output voltage to the nominal optimum battery voltage which is from 13.9-15.5 volts, the voltage set point is based on the batteries state of charge and estimated battery temperature. The battery voltage ramps up to the targeted set point at a rate of 20 mV per second.

Fuel Economy Mode
The generator battery control module will enter Fuel Economy Mode when all of the following conditions are true:

• Estimated ambient air temperature is equal to or greater than 0C (32F).

• The calculated battery current is less than 15 amperes and greater than - 8 amperes.

• The battery state of charge is greater than or equal to 80 percent.

• The rear defoggers are turned OFF.

• The electric cooling fans are on low speed or OFF.

The targeted generator output voltage is 13 volts. The generator battery control module will exit this mode once the criteria are met for Charge Mode or it will boost voltage to a pre-determined set point for the fuel pump, headlamps, or windshield wipers.

joecar
August 31st, 2008, 05:08 AM
thanks joecar.:grin:
i have already taken the steering wheel off and checked the ignition wires.
i put a resistor between 1073 and 1074 at the BCM but,
LOL it was the wrong one so the car would not turn over at all.
i am thinking that the DTC`s are being set because of the
voltage drop while cranking.
i know you suggested a bad ground but,
could the alternator cause this as well?Reading Howard's post reminded me that I wanted to say: your log shows voltage falling down to zero... a short in the alternator can cause that.

When that happens you should see motor stumble followed by instrument panel indicators lighting up;

What condition is your battery (batteries don't like shorts)...?

(a dead battery can kill an alternator, and vice-versa).

mr.prick
August 31st, 2008, 04:27 PM
the log is while cranking and key on, with a few seconds of key off.
the battery is new.
i hope it is a loose ground, that should be easy to find with the info
from that thread you linked to.
i'm thinking i pulled the grounds out on the driver's side cylinder head
when i changed injectors.
this started right after my injector swap.

hquick
August 31st, 2008, 06:15 PM
On one of the places I found that info it specifically mentioned the grounds on the backs of the heads.

joecar
September 1st, 2008, 05:46 AM
If you removed the bracket for the AIR inverter valve during the injector swap, then there's a good chance one or both grounds on the rear of the LHS side came loose (G110, G112).

mr.prick
September 2nd, 2008, 01:32 PM
all grounds that i could reach where good,
the alternator power wire was loose so i tightened it
and still it just cranks but won`t start.
the fuel pump reprimes after i stop cranking.
the instrument panel "surged" once. (needles spiked)
and i got a few more codes.

P1626
P1637
C0239
C0240
U1016
and some voltage measurements i took at the BCM.

Pin Wire Color Circuit No. Function

C2-----PPL/WHT-----1074 Ignition Key Resistor Return .12ohms @20k
D5-----PNK-----39 Ignition Positive Voltage 10.8 volts (the battery was a little low)
D6-----YEL-----43 Program Input 10.9 volts
D7-----WHT/BLK-----1073 Ignition Key Resistor Feed 10.2 volts
D8-----DK BLU-----229 Fuel Enable 2.6 volts <<<<<< problem

there is something up with the fuel enable voltage.
i`m supposed to check for an open or a short.
LOL i don`t know how to do this yet :grin:
i still suspect a bad BCM, tho i don`t know how to explain recovering from
this 2 other times before. :nixweiss:
i can`t retrieve the PCM calibration details. (ctrl+alt+pg up)

i should mention that there have been a few times in the past,
while driving down the road the car would out of the blue go super lean and sputter.
after pulling over and restarting all was well.

mr.prick
September 3rd, 2008, 11:12 AM
new battery reads 12.4volts
the fuel pump enable is 5volts (unhooked from BCM)
VATS and reduced power mode are still inactive
the stock PCM is not connecting.
the STAR, PCM, and BCM connectors looked good (no loose wires)
would a bad module other than the PCM keep flashscan from connecting?
are the any specific areas within the class 2 serial data circuit
that tend to fail i should look at or "easy" tests?

joecar
September 4th, 2008, 02:25 PM
Start at BATT.GIF and follow the letters...

I assumed 01 F-body, I think 99, 00 may be the same as 01, 02... let me know if you want 99 or 00.

mr.prick
September 4th, 2008, 04:34 PM
thanks. (2002)
this seems to be beyond my simple mind. LOL
why can i connect and log, read/clear DTC`s but
not download/upload to the stock PCM?
i guess those are different types of connections. :confused:
my new battery is 12.3volts, flashscan reads 11.8volts. :confused:
are all wires connected to the class 2 serial data circuit?
could an open anywhere in the car do this?

joecar
September 5th, 2008, 03:24 AM
Yes, scanning, logging, reading, flashing all use the same wire.


PCM reports 11.8V to scantool, but measurement across battery shows 12.3V...

This means the PCM power/ground circuits are dropping 0.5V... this is bad.


Key off, disconnect PCM connectors;
Key on;

Place DMM - probe on battery negative terminal;
with DMM + probe, check voltage on power pins in connector;
expect to see battery volts, if not, probe upstream on power circuit(s);

Place DMM + probe on battery positive terminal;
with DMM - probe, check voltage on ground pins inconnector;
expect to see battery volts, if not, probe downstream on ground circuit(s).

Extract the files from the attachment before viewing (to see the connector images).

joecar
September 5th, 2008, 03:31 AM
I edited my post.

Biggsy
September 5th, 2008, 09:29 AM
my new battery is 12.3volts, flashscan reads 11.8volts. :confused:


This seems to be normal, it does the same on my car.

joecar
September 5th, 2008, 10:26 AM
Oh, it does...?! :doh2: ...I'll go log mine.

mr.prick
September 5th, 2008, 01:05 PM
LOL
either way i have a problem with the "class 2 serial communications".
this happened 2 other times but i got it going after recharging the battery,
i think it`s from all the power i pull through the car. (inverter, stereo, extra sensors)
i took off the rubber boots on the +/- cable of the battery and they looked fine.
i even check the ground above the starter. :mad:
LOL
whats the easiest way to find an open circuit through miles of wire. :hihi:

joecar
September 5th, 2008, 01:25 PM
Disconnect all modules from the class 2 bus, and probe the bus for shorts/opens.

Not having power/ground to all modules can cause disruption on the bus, as can a module that won't stop chatting on the bus (for some reason it is trying to complain about something), as can some shorts, as can pulling too much power.

To find an open in a power circuit:
- connect DMM - to battery negative;
- using DMM + probe power circuit, starting closest to battery:
--> if DMM shows exact battery voltage, then open is downstream (away from battery);
--> if DMM shows a slight drop, continue probing downstream;
--> if DMM shows a large drop or floating, then you have just passed the open.

To find an open in a ground circuit:
- connect DMM + to battery positive;
- using DMM - probe ground circuit, starting closest to battery:
--> if DMM shows exact battery voltage, then open is downstream (away from battery);
--> if DMM shows a slight drop, continue probing downstream;
--> if DMM shows a large drop or floating, then you have just passed the open.

Even if a connection looks good, probe either side of it...
Also spraying it with a small amount of WD40 will internally clean it up.


I don't like using the cigar lighter to power the scantool because doing this can set up a ground loop...

a ground loop is when to "grounds" which are at different potentials wrt to each other are connected... the current that flows between them is the difference between their potentials divided by the resistance of the connection, and often this current can be large and can fry something.

mr.prick
September 5th, 2008, 03:15 PM
a ground loop is when to "grounds" which are at different potentials wrt to each other are connected... the current that flows between them is the difference between their potentials divided by the resistance of the connection, and often this current can be large and can fry something.

this is what i am thinking.
i also might change the ground wires for the hell of it. (big3)
then what to do when/if i find a bad wire. :doh2:
i guess it will be like eating spaghetti. :yucky:
thanks
:cheers:

mr.prick
September 6th, 2008, 05:06 AM
if i am doing this right,
the star has no voltage unhooked and 1.__ resistance at each pin.
i get 12 volts from the main fuse box and 1.__ resistance.
does this mean i have a bad ground/hot wire at the battery?

joecar
September 6th, 2008, 06:23 AM
if i am doing this right,
the star has no voltage unhooked and 1.__ resistance at each pin.
i get 12 volts from the main fuse box and 1.__ resistance.
does this mean i have a bad ground/hot wire at the battery?By star are you referring to the class 2 bus...?

Which wires are you ohming wrt which other wires...?

The DMM displays 1.___ for overrange (manual range) or for open-circuit/high-resistance (auto range)... are you set on auto range...?

Where do you see open circuit...?

Which circuit diagram are you looking at...?

Remember to not ohm a live circuit.

mr.prick
September 6th, 2008, 10:31 AM
i am checking each module`s wire to the star bus now.
i don`t think i was doing it right before.
PCM
blue 58 to STAR C - audible
blue 58 to OBDII pin 2 - audible
blue 57 to positive battery cable - audible

SDM (air bag)
SDM connector (dark blue wire) to STAR E - audible

EBCM
EBCM pin 25 (light blue) to STAR J - audible

mr.prick
September 7th, 2008, 01:21 PM
does anyone know where pin J meets the IPC?
or any reason connection cannot be made through OBDII port?

joecar
September 8th, 2008, 04:41 AM
does anyone know where pin J meets the IPC?
or any reason connection cannot be made through OBDII port?See the attached diagrams(look where splice pack SP200 connects to the module).

joecar
September 8th, 2008, 04:44 AM
I think your serial bus is ok... problem may be ground related or a bad module on the bus.

mr.prick
September 8th, 2008, 12:11 PM
I think your serial bus is ok... problem may be ground related or a bad module on the bus.

thanks for the IPC schematic. :cheers:

is the BCM part of the IPC?


do you mean a ground to one of the modules?

from what little i`ve seen on something like this has been,
a possible open on the bus or a failed module.
i don`t think bad ground anywhere other than whats on the bus would do this.

i am checking the bus first then moving on.
all the grounds i have checked go all the way back to the
battery cable end.

here`s what i recall checking so far
PCM
blue 58 to STAR C - audible
blue 58 to OBDII pin 2 - audible
blue 57 to positive battery cable - audible
red 1 to negative battery cable - audible
red 40 to negative battery cable - audible

SDM (air bag) connector (dark blue wire) to STAR E - audible

EBCM pin 25 (light blue) to STAR J - audible

BCM to battery (+/-) - audible

cig lighter (+/-) - audible

DLC
DLC 4 to negative battery cable - audible
DLC 5 to negative battery cable - audible

IPC to (gray) STAR L - audible

joecar
September 9th, 2008, 02:52 AM
EBCM = electronic brake control module (aka ABS).
BCM = body control module

Unfortunately, on F-body the BCM is not on the Class 2 bus.

Keep probing... you will find it.

You can also run one module on the bus at a time... see if one module in particular causes DTC's to pop up.

mr.prick
September 9th, 2008, 11:42 AM
EBCM = electronic brake control module (aka ABS).
BCM = body control module

Unfortunately, on F-body the BCM is not on the Class 2 bus.

Keep probing... you will find it.

You can also run one module on the bus at a time... see if one module in particular causes DTC's to pop up.

this conflicts with what i was told by Blacky.....


am i correct to assume the BCM is part of the IPC?
on the class-2 com.



Yes, the BCM communicates on the class-2 network.

When network codes get set a fair amount of "default" value processing goes on in the PCM. Basically after a network fault code, the PCM "distrusts" data from other modules and substitutes default values for some or all of them. So I am not surprised at a poor performing engine if the PCM has network codes. I don't think the poor performance is caused by any physical fault, just the PCM dumbing itself down due to the network errors (but I could be wrong). The network errors could be caused by faulty loom, connectors or even a faulty module dragging the whole bus down with it.

The reason I mentioned high speed mode is that you said you could read codes etc but could not read/flash. The only time high speed mode is used is when reading/flashing which is when you say it fails. So I was trying to think of what was different between just reading codes (at 1x speed) and reading/flashing (at 4x speed).

If the class-2 network is flaky and has some short or open circuit even intermittently, then it will be magnified during high-speed read/write because the VPW transceivers switch off their wave shaping filters during high speed mode, so the tolerance to interference will be lower.

joecar
September 9th, 2008, 04:18 PM
Lol...:hihi:...all other car models are different than F-body... :gossip:

F-body BCM is not connected to the Class 2 bus, and has no bus style connection to any other module...

(this makes it a PITA to diagnose BCM problems, as you have discovered)

See attached diagrams (All Else.zip and PCM.zip) for 2001/2002 F-body.

Even the high end Genisys/Snap-On scantools do not see the BCM when connected to the F-body DLC...

By contrast, Y-body has just about everything on the Class 2 bus, see attached... :doh2::doh2::doh2: ...it's a wonder that the tunetool can get bus bandwidth.

So Paul was correct about the BCM being on the Class 2 bus, for everything except F-body... :)

mr.prick
September 10th, 2008, 11:21 AM
it`s not "on the bus", but is`nt it part of the IPC?

i am suspecting the BCM mostly because of the P1626
as well as all the Uxxx codes.

i was also hoping for an easy fix. :angel_innocent:

also something very odd now,
i removed the radio an was able to start the car and it stayed running,
but flashscan could still not connect.
after 3 starts the car is once again in a non start/running state.
this is most likely a fluke.

joecar
September 10th, 2008, 01:20 PM
it`s not "on the bus", but is`nt it part of the IPC?The BCM is not on the bus, and it's not part of the IPC... it's all by itself...

See the diagrams for BCM and IPC.

The IPC is located in front of driver;
The BCM is located in passenger side footwell;

The BCM illuminates the following LEDs on the IPC display (the dash):
- Seat Belt,
- Security

And it also illuminates the Theft/Alarm LED on top of the dash.

joecar
September 10th, 2008, 01:46 PM
Ok, I reread your post #1:
- getting fuel,
- not getting spark;

Post #34: removed radio and motor started, but won't run after 3 starts...

I assume starter cranks ok each time.


Check with scantool that PCM's fuel enable state is on and VATS state is off...
i.e. is PCM not fueling dues to VATS/BCM theft reason (are you having key pellet trouble...?)...?

Verify that you are getting fuel (I'm assuming so).
Verify that you are not getting spark (I'm assuming not).

Do you have a LED test light (i.e. uses red/green LED instead of a light bulb)...?
This draws low current which prevents damaging the PCM's internal sources/sinks;
Get one from local parts store;

Refer to coil diagrams in PCM folder I posted above...

If no spark, then coils are not firing...
disconnect coil primary and with key on check:
- battery voltage between pins D and A;
- zero (or almost zero) volts between pins B and A;
If those fail, then there is a grounding problem or a PCM with dead sources/sinks;

then while cranking, check:
- voltage "signal" between pins C and B using LED test light;
If that fails, then must determine why there is no coil trigger signal (go upstream)...
open/short circuit, or grounding problem;

If those all pass and you get this far, then something's wrong with the coils or grounding or spark plugs/wires.

mr.prick
September 10th, 2008, 02:53 PM
Ok, I reread your post #1:
- getting fuel,
- not getting spark;

Post #34: removed radio and motor started, but won't run after 3 starts...

I assume starter cranks ok each time.


Check with scantool that PCM's fuel enable state is on and VATS state is off...
i.e. is PCM not fueling dues to VATS/BCM theft reason (are you having key pellet trouble...?)...?

Verify that you are getting fuel (I'm assuming so).
Verify that you are not getting spark (I'm assuming not).

Do you have a LED test light (i.e. uses red/green LED instead of a light bulb)...?
This draws low current which prevents damaging the PCM's internal sources/sinks;
Get one from local parts store;

Refer to coil diagrams in PCM folder I posted above...

If no spark, then coils are not firing...
disconnect coil primary and with key on check:
- battery voltage between pins D and A;
- zero (or almost zero) volts between pins B and A;
If those fail, then there is a grounding problem or a PCM with dead sources/sinks;

then while cranking, check:
- voltage "signal" between pins C and B using LED test light;
If that fails, then must determine why there is no coil trigger signal (go upstream)...
open/short circuit, or grounding problem;

If those all pass and you get this far, then something's wrong with the coils or grounding or spark plugs/wires.

the starter cranks,
i`ve logged GM.STATE02 and VATS is inactive,
GM.STATE14 all coils ok
i pulled plug #2 and it was a little wet.
WBO2 AFR was quite lean though.
remember the car lopes badly so data maybe skewed.

would on open ANYWHERE on the car cause the
non connection problem?
like a tail/headlight.

the fact i can`t read/flash the stock PCM but log PIDs and DTCs
was explained by blacky via PM


i cannot connect through the OBDII (DLC) port to
flash/read the PCM. (stock PCM)
i can scan DTCs and PIDs though.

i have checked all fuses, the serial connector (star)
PCM, and DLC for continuity

is there anything else that can look into
that is causing this disruption in the serial com?
can a failed module (IPC, EBCM and SDM)
cause this?

thanks


If it is a CAN based vehicle then I cant think of anything, but if it is a VPW based vehicle, then chances are one or more modules are failing to honor the high speed read/program mode. If just one module does not honor the high-speed mode then it can cause faults on the entire class-2 bus.


4.1.5 4X Mode
4X mode is entered when the host loads the 4X mode bit configuration into the configuration
byte.
During 4X mode, transceiver waveshaping is disabled, thus allowing the DLC to operate
without any slew rate limitation. 4X mode affects only the transmitted and received
symbol timing logic of the DLC (including the digital filter).
4X mode allows communication on the multiplex bus to be performed at four times the
normal bit rate.
This high speed transfer function does not work properly unless all transmitting nodes
on the J1850 bus are in 4X mode. Selected receivers may be configured to ignore high
speed frames until a BREAK symbol is received. Detection of a BREAK symbol on the
J1850 bus returns the DLC to normal mode.


all the hot and grounds that i`ve checked have been audible
all the way to the battery cables.
i hope this is the correct way to do this. (battery disconnected)
i figure that if i get an audible all the way to the very end of the source of power/ground than there is no open anywhere.
also i have checked each module`s to serial connector (star) wires
also the PCM to 12volt/ground, fuel enable and, DLC (obd2 port)

the BCM seems to be working, i.e
i can program the alarm and all the wires have the right voltage
and i hear the relays click.
but once the car dies or i switch the ignition off i can
hear the fuel pump "re-prime".

is there any way to test any of the modules with flashscan?

Blacky
September 10th, 2008, 04:55 PM
this conflicts with what i was told by Blacky.....
Sorry, my bad. I made a big, bad, wrong assumtion - go with what Joe says.
Paul

joecar
September 11th, 2008, 03:45 AM
Also log GM.VATS.

Disconnect all 4 modules from bus (PCM, EBCM/ABS, IPC, SDM), and reconnect one at a time... each time, cycle ign key, connect scantool and see if U1016 pops up...
it seems to me that U1016 is posted by whichever module is trying to get on the bus but is not able to dues to another module hogging it.

I don't like the ohms/continuity test because it draws very little current... some bad connections seem ok when passing low current, but fail with larger current (the voltage drop is larger with larger current... V=I*R)...

With DMM set on 20VDC scale,
with batt. connected,
place DMM neg. probe on batt. neg.,
with DMM pos. probe check that:
- all hot nodes read close to battery voltage;
- all gnd nodes read close to zero volts;
Post your readings.

joecar
September 11th, 2008, 03:47 AM
Sorry, my bad. I made a big, bad, wrong assumtion - go with what Joe says.
Paullol... :grin:... F-body is different in various ways... even the chassis is asymmetrical left-right... it's an engineering wonder it tracks in a straight line... :doh2:

mr.prick
September 11th, 2008, 12:29 PM
i could not find GM.VATS
unplugging the IPC alone off the bus gave me intermittent VATS
active-inactive, U1016, U1040, U1096, and, P1626.
i imagine that any module off the bus will cause Uxxxx codes and
maybe a non connect.

when the car starts it reeks of gas.
but forget about the non running condition,
i want to connect completely to flash.
i don`t see why i cannot connect completely to flash/read.
i am going to test my V2 on someone else`s car to see if i have an
issue with flashscan. (i doubt it)

LOL
are you saying i wasted my time with the continuity tests?:confused:
from what i`ve read, a continuity test should be enough
as long as it passes, if it does not then you look to see if it is
shorted to ground or power.
i`m about ready to give up and have it towed to a dealership.:throw:
but i`m leary of them not being able to find the problem.

joecar
September 11th, 2008, 01:39 PM
Oh, GM.VATS might be a later PCM... :doh2:

Hmmm... I just remembered unplugging the IPC may cause the PCM to complain because it sends VSS messages to the IPC...:doh2:

Your continuity tests are good... :)
I was just saying I prefer measuring volt drops, but that's not always feasible.

And you're certain that all the grounds are good...?
And you're certain that all the fuses/links are good...?


when the car starts it reeks of gas.I'm beginning to think your PCM may be half dead...
Do you have a spare PCM that's already programmed...?

When it doesn't start, are you certain it is due to no spark...?
If so, have you tried diagnosing the no spark...?


i`m about ready to give up and have it towed to a dealership.:throw:
but i`m leary of them not being able to find the problem. Some technicians are good, they will pinpoint the component and replace that only...
while other technicians will shotgun and replace everything in sight.

mr.prick
September 11th, 2008, 01:43 PM
do you know if one of the modules were to be disconnected,
if flashscan could read/flash the PCM?
maybe disconnect one of you modules then check status of your PCM for me.:redface:

joecar
September 11th, 2008, 01:47 PM
That would be a good test...
remove all modules from the bus except the PCM...
then try to read the PCM's flash...
if that works, turn key off, add another module, and try again;

if the PCM is the only module and you can't read from it, then:
- check that the PCM's power/ground connections/wires are all good;
- check that battery voltage is at least 12V.

joecar
September 11th, 2008, 01:49 PM
When a bench harness is used, the PCM is the only module present, and the tunetool can read/write the flash...

I can't pull my car apart right now, I'm still at work...:angel_innocent:

joecar
September 11th, 2008, 01:54 PM
You may want to inspect the PCM's pins... see if any are bent or pushing in.

joecar
September 11th, 2008, 01:56 PM
When it doesn't start, are you certain it is due to no spark...?
If so, have you tried diagnosing the no spark...?I'll dig thru the service manual tonite to find the pages relevant to this.

mr.prick
September 11th, 2008, 02:02 PM
i have the stock PCM in right now.
the last time this happened i could not read the VIN with RR installed,
then i put the stocker back in and it could not connect either.
for some reason the condition went away. :confused:

there where a few times while driving down the road,
the car just went way lean even with the RR added fuel like crazy.

if it is possible to remove all other modules except the PCM
from the stock harness and still connect to flash/read
then i could nail it down to a module failure,
i just need to be absolutely certain that by unplugging the other modules
from the stock harness that it will or will not cause this problem
on a working vehicle.:hihi:

joecar
September 11th, 2008, 02:13 PM
Oh, when you unplug or plug a module's connector(s), you have to have the battery disconnected first.

mr.prick
September 11th, 2008, 03:24 PM
Oh, when you unplug or plug a module's connector(s), you have to have the battery disconnected first.

ok
i`m just going to unplug the module`s wire at the star bus,
unless i should completely disconnect the module of the harness.
i wonder which way would be best. :gossip:

joecar
September 12th, 2008, 05:43 AM
Pulling the module's wire at the star is ok, no need to disconnect battery.

mr.prick
September 12th, 2008, 01:05 PM
with only the PCM on the bus i still get no connection.
the fuel pump still recycles after cranking stops. :bad:

GM.VTD shows vehicle theft deterrent fuel system - enabled
i also have 2.5 volts at the BCM fuel enable wire when it should be 5 volts. :bad:
it is 5 volt without the BCM plugged in and,
the key signal feed/return wires give "1.__" with the BCM plugged in
with the BCM unplugged i get the same resistance as my key.

LOL
is it possible that the BCM would keep the PCM from being flashed if in
a permanent theft deterrent state?
seeing how it is the security system

i imagine this would be the case to keep someone from swapping PCMs/BCMs
to steal the car.

i know the VATS relearn procedure,
are there steps to reset that so i know it in relearn mode?

joecar
September 12th, 2008, 02:14 PM
with only the PCM on the bus i still get no connection.
the fuel pump still recycles after cranking stops. :bad:If the PCM continues to cycle the pump, then PCM is bad.


GM.VTD shows vehicle theft deterrent fuel system - enabled
i also have 2.5 volts at the BCM fuel enable wire when it should be 5 volts. :bad:It's a 5V square wave, so you will see 2.5VDC (rms).


it is 5 volt without the BCM plugged in and,
the key signal feed/return wires give "1.__" with the BCM plugged in
with the BCM unplugged i get the same resistance as my key.
LOL
is it possible that the BCM would keep the PCM from being flashed if in
a permanent theft deterrent state?
seeing how it is the security system

i imagine this would be the case to keep someone from swapping PCMs/BCMs to steal the car.I don't know... when I swapped my PCM I could still start and run for 2 seconds before relinking VATS.


i know the VATS relearn procedure,
are there steps to reset that so i know it in relearn mode?Try relinking VATS.

joecar
September 12th, 2008, 02:27 PM
When VATS is active, the PCM does not fire the injectors.

mr.prick
September 12th, 2008, 02:38 PM
If the PCM continues to cycle the pump, then PCM is bad.

It's a 5V square wave, so you will see 2.5VDC (rms).
.
does this mean that once the BCM is connected to the harness the voltage should drop by half?
also the key feed and return have no resistance when connected to the BCM.
VATS and all the other tune.exe options are locked out because of the non connection.

this was happening with my RR and stock PCM.
i don`t see how both of the could be crunked but anything is possible.
this problem was intermittent.
last time the car would not start/run i found i could not read the VIN through the RR
all else was fine, i could upload/download.
i put in the stocker and it would not upload/download.

i just hooked up flashscan to my laptop to run HAPI and it won`t power up.
i seem to have a short in my USB cable.
and HAPI won`t load.
maybe this is why i can`t flash and, maybe something is wrong with the car.

LOL the drama

mr.prick
September 13th, 2008, 02:45 AM
a new USB cable did not help with connection.:mad:
some codes
P0103
P0103
P1626
U1000
U1000
U1016
U1040
U1096
the MAF codes can be explained by the tune installed on the PCM
but the P1626 is VATS and it is accompanied by the U network codes.
as it always is. :bawl:

i need to find out why HAPI won`t load either.
it is in my firewall and i turned off the firewall and it still won`t load.:confused:

mr.prick
September 13th, 2008, 04:56 AM
here's a log after i got it started.(don`t ask me how)

3886

as you can see it is pretty whacked out.
spark advance is all over the place, most likely due to
swapping PCMs without uploading the tune that was in the RR.
the tune in the stock PCM is from long ago.

joecar
September 13th, 2008, 05:27 AM
here's a log after i got it started.(don`t ask me how)

3886

as you can see it is pretty whacked out.
spark advance is all over the place, most likely due to
swapping PCMs without uploading the tune that was in the RR.
the tune in the stock PCM is from long ago.
This may mean the PCM has failed:
STATE04-NVM "non-volatile memory" = Failed

This may also mean the PCM has failed (it is not controlling the altenator):
STATE01-ALT-L "alternator L terminal" = No Voltage

mr.prick
September 13th, 2008, 07:16 AM
This may mean the PCM has failed:
STATE04-NVM "non-volatile memory" = Failed

This may also mean the PCM has failed (it is not controlling the altenator):
STATE01-ALT-L "alternator L terminal" = No Voltage


bad alternator/connection to = no connection to the PCM?
this wire has 9.5 volts with IGN on.
0 volts ING off.
to PCM red 15 - audible

the car has started 3 times even with an outdated/bad tune installed.
now it won`t start again.
unplugging the BCM the plugging it back in gets the car to start and run.(somewhat)

again i wonder if the BCM can cause havoc with the communications between modules.

could someone with an fbody unplug your BCM and see if you can
read/check status of the PCM......please. :help2:

joecar
September 13th, 2008, 05:25 PM
I'll see if I can do this tomorrow...

mr.prick
September 14th, 2008, 07:22 AM
the inside fuse panel airbag fuse slot seems to be open.
from the airbag to the fuse is good.
from the fuse to the battery cable and the under hood fuse box bolt is "1__".
i don`t have any drawings of the inside fuse panel, so i`m not sure what to make of this.
LOL
does the airbag work by being powered up in an accident?

joecar
September 14th, 2008, 09:05 AM
In All Else.zip look at the folder "SIR" (supplemental inflatable restraints).

The SIR (airbag) module is powered when ignition key is on... check for batt volts at airbag fuse with key on.

I'm sorry, I haven't had time to remove the BCM connectors yet today, my wife's got an event to go to, so I am a bit rushed... I do apologize.

mr.prick
September 14th, 2008, 09:48 AM
thanks for the help.
with key on everything is fine.

joecar
September 14th, 2008, 04:49 PM
Ok, finally got home from said event...

I removed the 3 connectors from the BCM...

Key on, scantool shows DTC P1626 and no other DTC's.

With BCM removed, starter does not crank (as confirmed by wire diagram, BCM controls starter relay); scantool shows VTD fuel disabled.

Oh, and I could read the PCM flash contents.


Reconnected BCM, scantool shows VTD fuel enabled, starter cranks and motor runs.

joecar
September 14th, 2008, 04:50 PM
thanks for the help.
with key on everything is fine.Are you saying it all now all works...? :cheers:

You have to know why it now all works, otherwise you may be left on the side of the road late one night... :bad:

joecar
September 14th, 2008, 05:10 PM
BTW: the fuel enable signal is a 50Hz 0-5V 50%dc square wave.

mr.prick
September 15th, 2008, 11:24 AM
Are you saying it all now all works...? :cheers:

You have to know why it now all works, otherwise you may be left on the side of the road late one night... :bad:

no,
i just meant the airbag fuse is good.

joecar
September 15th, 2008, 11:30 AM
Oh, ok, airbag fuse (I had loss of context)...

mr.prick
September 15th, 2008, 11:42 AM
i have seemed to make a breakthrough.
this all started awhile after a new injector swap so,
i unplugged all my injectors and now the SES light flickers and
the fuel pump moans while turning the key on.
i may have an open/short in the injector harness.

all injector wires to the BLUE (C1) connector are audible.
i assume the RED (C2) wires need to go through the fuses,
because they where not audible.

joecar
September 15th, 2008, 03:07 PM
Refer to diagram PCM/700032.gif...

Power side of injectors:
Bank 1 injector PNK/639 wires go to INJ1 fuse (which also feeds bank 1 ignition coils).
Bank 2 injector PNK/839 wires go to INJ2 fuse (which also feeds bank 2 ignition coils).

PCM side of injectors:
These all go to C1/BLU connector.
None of them go to C2/RED.

joecar
September 15th, 2008, 03:11 PM
Do you mean:
- SES light comes on...?
- fuel pump runs for about 2 seconds...?

joecar
September 15th, 2008, 03:12 PM
Check for shorts in the C1 injector wires...

mr.prick
September 15th, 2008, 04:11 PM
Do you mean:
- SES light comes on...?
- fuel pump runs for about 2 seconds...?

the SES flickers, the other light/gauges didn`t light up and,
the fuel pump didn`t quite come on.:hihi:
it moaned. :doh2:
battery voltage was 11volts though.
i`v had it lower and it never did that. :bad:


Check for shorts in the C1 injector wires...

i`m not sure of the best way to check these but,
i checked the C1 (blue) wires from the C1 pin to the injector and they all were audible.
i think i need to check them with the PCM plugged in and they should be 1__? :confused:
they are the ground wires and should be open until the PCM closes them?:confused:

the C2 (red) wires need to be done with the battery hooked up/key on, the fuses are not blown so i don`t have a short in the pink (hot) wires.
i assume they should be 12 volts when probed.

LOL they pulsed when i could get the car to run.:angel_innocent:
unhooking the injectors made some noticeable changes,
hooking them back up didn`t help either.
if battery volts were`nt too low then i disturbed something.

joecar
September 15th, 2008, 04:39 PM
SES flickers and fuel pump does not get enough power... either battery is too low or bad power/ground connection... how old is you battery...?

Do not check continuity/ohms with PCM plugged in, the PCM might get damaged;
Do not check continuity/ohms with battery connected, DMM may get fried.

Check that each injector wire is not shorted to another injector wire, or to power/ground wires.

Yes, they are the injector "ground" wires; they are normally open; the PCM closes them to ground to fire each injector.

Inspect injector wires back into wire harness, look for pinched, sharp bends, stretching, burnt, melted, worn/rubbed insulation....

Yes, pink wires are 12V.

The pink wires pulsed voltage...? That's bad...!!!

Do you have a battery charger...?

mr.prick
September 15th, 2008, 05:12 PM
SES flickers and fuel pump does not get enough power... either battery is too low or bad power/ground connection... how old is you battery...?
new (with some time with IGN on)


Do not check continuity/ohms with PCM plugged in, the PCM might get damaged;
Do not check continuity/ohms with battery connected, DMM may get fried.

Check that each injector wire is not shorted to another injector wire, or to power/ground wires.

:hihi:


Yes, they are the injector "ground" wires; they are normally open; the PCM closes them to ground to fire each injector.
other than checking them the way i did, i was`nt sure how to go about this.
Inspect injector wires back into wire harness, look for pinched, sharp bends, stretching, burnt, melted, worn/rubbed insulation....

looks like i`ll be opening the wire loom.



The pink wires pulsed voltage...? That's bad...!!!
i meant the injectors pulsed when i logged them. (IBPW)

Do you have a battery charger...?
yes,
i had been using it while sitting with IGN on but the battery
has been used without it as well.

i`ve heard if injector wires wearing out over time,
maybe i split something back when i changed injectors and,
it took some time to manifest. :confused:

:confused: i guess i have a short to ground, because of the VPW class 2 com.
and the non read/flash situation. :confused:

joecar
September 16th, 2008, 02:59 AM
Remember to set ignition key to off before disconnecting battery/PCM.
Disconnect battery and PCM;

Set ignition key to on;

remove all injector connectors from injectors;
then probe both pins in each injector connector:
- check for lack of continuity to battery pos/neg cables;
EDIT: pink wire (only) should have continuity to battery pos; the other wire should not.
- check for lack of continuity to INJ1 and INJ2 fuses (except for pink wire which should have continuity to both fuses);
- check for lack of continuity between the 2 pins;
- check for lack of continuity to both pins in other 7 injector connectors (except for pink wire which should have continuity to other pink wires);

then ohm each injector, should see 12 ohm across each injector.

Remember to set ignition key to off before reconnecting PCM/battery.
Reconnect PCM and battery.

mr.prick
September 16th, 2008, 11:45 AM
Remember to set ignition key to off before disconnecting battery/PCM.
Disconnect battery and PCM;

Set ignition key to on;

remove all injector connectors from injectors;
then probe both pins in each injector connector:
- check for lack of continuity to battery pos/neg cables;
- check for lack of continuity to INJ1 and INJ2 fuses;
- check for lack of continuity between the 2 pins;
- check for lack of continuity to both pins in other 7 injector connectors;

then ohm each injector, should see 12 ohm across each injector.

Remember to set ignition key to off before reconnecting PCM/battery.
Reconnect PCM and battery.

injector pink wires
to NEG- is audible
to POS+ is 466 :confused:

yesterday battery volts were 11
i unhooked the battery last night, today battery was 7volts.
connected to a charger and with the key on the battery gauge is low
and i watched it drop to nothing. :confused:

more time on the charger and the battery has 11.7 volts,
attempted to crank and all power is lost.

joecar
September 16th, 2008, 12:32 PM
injector pink wires
to NEG- is audible
to POS+ is 466 :confused:PCM is disconnected, and ignition key is on, right...?

This is bad... pink wire(s) shorted to ground/NEG-.

This is bad also... pink wire (only) should show continuity to POS+... are you saying DMM shows 466 ohms...? it should show close to zero ohms.

I made a mistake in post #76... see my correction:

EDIT: pink wire should have continuity to battery pos; the other wire should not.

yesterday battery volts were 11
i unhooked the battery last night, today battery was 7volts.
connected to a charger and with the key on the battery gauge is low
and i watched it drop to nothing. :confused:

more time on the charger and the battery has 11.7 volts,
attempted to crank and all power is lost.Charge battery for a few hours on slow charge, it should be fully charged by then... if not, then battery is traumatized.

mr.prick
September 16th, 2008, 12:51 PM
PCM is disconnected, and ignition key is on, right...?

This is bad... pink wire(s) shorted to ground/NEG-.

This is bad also... pink wire (only) should show continuity to POS+... are you saying DMM shows 466 ohms...? it should show close to zero ohms.

I made a mistake in post #76... see my correction:

Charge battery for a few hours on slow charge, it should be fully charged by then... if not, then battery is traumatized.


i was wondering about that.
i checked again with battery out (in trash)
PCM disconnected and key on
pink wire is audible to both +/-

i am going to get another battery.
i did not buy the same one that i had before,
it seems to me that my last one could take more "on time".

joecar
September 16th, 2008, 12:56 PM
What I am trying to say is:

From diagram PCM->700032...

with battery and PCM removed...



all pink wires (injector positive side) should have continuity with battery POS+ and with each other, but not with battery NEG-.



all other wires (injector negative side) should have no continuity to any of theses:



NEG-
POS-
pink wires

Are you saying that:
1. the pink wires are shorted to NEG-...?
2. the pink wires have resistance (bad connection) to POS+...?

joecar
September 16th, 2008, 01:07 PM
In diagram attached...

pink wires (injector positive side) should have continuity (0.2 ohms maybe) with INJ1/INJ2 fuses and with POS+ (ignition key on)...

pink wires should be isolated ("inifinite ohms 1.__") from NEG-.

with PCM disconnected: the other wires (injector negative side) should be isolated from both POS+ and NEG-.

mr.prick
September 16th, 2008, 01:29 PM
key on battery+PCM disconnected
injector pinks to ground are audible
so is the main fuse box, cig lighter ect.
if this is bad i won`t feel so bad for killing 2 new batteries. :hihi:

swingtan
September 16th, 2008, 02:40 PM
OK, I'm joining in late but may have an idea.

So far, we have....


The car will not start when attempting a "normal" start.
If you hold the TB at WOT, the car will start, but run rough and there is a Strong fuel smell. I'm also assuming it's running very rich.
Recently, it had new injectors fitted.
Disconnecting the injectors produces an audible change in the fuel pump sound.


From memory, applying anything over a set amount of throttle, engages "Clear Flood Mode", which disables the injectors on the start. Has any one thought about the possibility of the car simply running way too rich to start? In the past I've checked this by attempting to start normally, then after a few goes removing the fuel pump fuse / relay and starting the car with no pump running. If it cranks for a while, then starts, then it's a case of finding why the car is so rich on cranking.

With the change in fuel pump sound, I wonder if the injectors are leaking? Or possibly a short in the injector loom is causing the injectors operate when they shouldn't, providing too much fuel.

Simon.

mr.prick
September 16th, 2008, 03:15 PM
actually,
i cannot connect properly to the PCM.
for what ever reason this may be,
it causes a loss of communication between
the PCM, IPC, EBCM, and SDM.

resulting in the fuel pump enable signal to be lost
causing the car to limp. (400RPM-/+)
this may be a short/open circuit somewhere,
but now i am wondering if it first was a dead/dying battery
and i possibly was give a bad/wrong type of battery from the parts counter.

it is definitely electrical in nature because
i cannot upload/download a tune to the PCM, retrieve calibration details, or
perform a VATS relink.
even with a battery charger connected.

i can log PIDs/DTCs.

swingtan
September 16th, 2008, 04:34 PM
lol.... I was looking at your avatar and AC-DC "Hard As a Rock" came on......

Does the PCM get overly warm?

When checking the injector wires, it may be worth unplugging the injectors, and testing for shorts between the injector wires.

When testing the PINK wires for continuity to GRND, it would be good to remove the injector fuses, as you may have a path to ground on the battery side of the fuse.

It may be time to invest in a bench loom........

mr.prick
September 16th, 2008, 05:26 PM
lol.... I was looking at your avatar and AC-DC "Hard As a Rock" came on......

When checking the injector wires, it may be worth unplugging the injectors, and testing for shorts between the injector wires.

When testing the PINK wires for continuity to GRND, it would be good to remove the injector fuses, as you may have a path to ground on the battery side of the fuse.


LOL this makes some sense. :redface:
i didn`t check the ground wires for the injectors because i assumed
they would be opened when the PCM is off line.
then again a closed would be bad then, right?
i am merely an immature electrician. :throw:


It may be time to invest in a bench loom........

or a wire tracer. http://smiliesftw.com/x/msn_011.gif (http://smiliesftw.com)



Does the PCM get overly warm?
as far as the PCM temperature,
i never though to check it.
http://smiliesftw.com/x/ill.gif (http://smiliesftw.com)

i`ve got 2 PCMs and i`m fairly certain it has to do with
how power is getting to the PCM or a ground.
when the key is on the PCM is either not getting enough power or
the power is inconsistent (surging/dropping) http://smiliesftw.com/x/dunnored.gif (http://smiliesftw.com)
keeping me from reading/flashing through the OBDII port.
my RR worked perfectly,
in fact there were a few time when this phenomenon happened while
driving and, all fuel stopped (fuel enable signal lost) and
the RR kept adding fuel,
to no avail. http://smiliesftw.com/x/catfight.gif (http://smiliesftw.com)

joecar
September 16th, 2008, 05:28 PM
I agree with Simon... test continuity of "positive" wiring to ground, removing fuses until continuity is lost... something is shorting "positive" to ground.

joecar
September 16th, 2008, 05:36 PM
Oh, at the top of the diagram it says "Hot with ignition relay energized"...

When battery is disconnected, use a fused jumper wire in place of the relay so you can check wiring all the way back to battery cable.

joecar
September 16th, 2008, 05:36 PM
Study up the diagrams I posted in the zip files.

mr.prick
September 17th, 2008, 12:35 PM
not sure if i`m doing this right but,
with the battery + PCM disconnected, key on and DMM connected to
battery pos+ and neg- cable ends there is a slight audible,
unplugging the GAUGES fuse gives me 072-082 reading and no audible.
only unplugging the GAUGES fuse stopped the weak audible.
should`nt this read 1__?

joecar
September 17th, 2008, 01:37 PM
With GAUGES fuse removed, check circuit 39 (downstream of the fuse) for shorts to NEG-.

With the GAUGES fues removed, if audible stopped, then there is isolation/load between POS+ and NEG-, and DMM should show 1.___ (isolation) or some number like 072 ohms (load).

If continuity mode is audible, then there is a short to ground, and DMM should show 000 (or close to it).
If there is isolation, then the DMM should show 1.___.
If there is load, then the DMM should show some number like 072 ohms.

joecar
September 17th, 2008, 01:38 PM
Look at what devices are downstream of the GAUGES fuse...

Remove the connector for each device until you isolate the short to a device.

mr.prick
September 17th, 2008, 02:33 PM
Look at what devices are downstream of the GAUGES fuse...

Remove the connector for each device until you isolate the short to a device.


so, i did do it right? :hihi:
i got the idea here
http://en.allexperts.com/q/Electrical-Wiring-Home-1734/short-ground.htm
this is with key on only.

basically everything here 3906
and here 3907 is now suspect.
:grin:

joecar
September 18th, 2008, 02:26 AM
Yes, that's how to do it. :cheers:

mr.prick
September 18th, 2008, 01:47 PM
after removing most of the devices from the GAUGES fuse
it was still audible to ground.

i unbolted the wire connector under the dashboard 3911
and tested the box junction to the I/P fuse box - audible

unhooked the pink wire is audible to the main FB and the I/P FB. :confused:
like the box junction to the I/P fuse box,
this should only be audible to the main fuse box
because this is where it originates.
the audible is also weak sounding.

in the main FB there a tons of pink wires,
some of them seem to go to the INJ1/INJ2 fuse.

remembering that the injector pink wires are audible to the ground wire
with the battery and PCM disconnected,
this leaves me pondering the link between GAUGES and the fuel injectors,
or all the other pink wires. :doh2:

joecar
September 19th, 2008, 02:15 AM
The short may be in the harness... was it fine before swapping injectors...?

mr.prick
September 19th, 2008, 11:17 AM
the last mod i did was injectors so,
it maybe in the injector harness.
with the PCM unhooked i don`t see how the injector hot wires
would be audible to the battery ground.
i have not check all of them but,
it seems that all pink wires (12volt switched power)
are audible to the ground cable with key on and off.

swingtan
September 19th, 2008, 11:50 AM
Have you pulled the Injector fuses yet and tested the hot wires again? I still think there may be some other CCT to ground elsewhere that may be hiding the problem. Then again, if there was a short to earth on the GRND side of the injectors, it could cause them to open partially or fully dumping fuel into the engine making it too rich to run.

Simon

mr.prick
September 19th, 2008, 01:26 PM
Have you pulled the Injector fuses yet and tested the hot wires again? I still think there may be some other CCT to ground elsewhere that may be hiding the problem. Then again, if there was a short to earth on the GRND side of the injectors, it could cause them to open partially or fully dumping fuel into the engine making it too rich to run.

Simon

the injector pink (hot) wires are audible (closed) to ground
with the PCM disconnected. :confused:
i am a bit dim :hihi: when it comes to electrical wiring but,
the way i understand it is that the injectors get grounded through the PCM.
with the PCM offline the pink wires at the injectors
should be open.(notaudible)

all pink wires are hot switched power and should be closed with
the ignition off, they are open even with the ignition off and the IGN relay removed.

joecar
September 19th, 2008, 08:54 PM
Remove the INJ1 and INJ2 fues, are the pink wires still shorted...?

mr.prick
September 20th, 2008, 03:34 AM
Remove the INJ1 and INJ2 fues, are the pink wires still shorted...?

PCM unplugged fuses and IGN relay in place key off and on - yes

PCM unplugged fuses removed key off/on - no

PCM unplugged relay removed key off/on - yes
3912
IGN relay pin B3(red) - open to ground(good)
IGN relay pin B1(black) - closed to ground(good)
IGN relay pin C1/C3 - closed to ground(bad):confused:

basically, all pink wires and some yellow wires that are connected to them
are closed to ground key on and off.

mr.prick
September 21st, 2008, 05:17 AM
probing around fuse box #2 (under hood lower)
i found that all but the starter fuse was closed to ground
i removed the fusible links and they (fuses) are still closed (audible)
the fusible links are not closed to power or ground.
also the PCM IGN and ABS IGN have a muted audible,
the rest are clear.

this is with the positive linking wire (short red between fuse boxes) disconnected.
if i do have a short it seems to be inside the car.

joecar
September 21st, 2008, 06:57 AM
Check the fuse panel on LHS of dash.

mr.prick
September 21st, 2008, 08:37 AM
i have checked all i can.
every pink (hot switched) is audible to ground.
maybe somewhere there is a melted wire.
everything seems to work fine though,
all lights, and the stereo come on.
the SES and check gauges light stay on.

i am trying to think of a common point for all pink wires.
even with the I/P and lower fuse boxes disconnected from each other
all pinks are closed to ground.

LOL
i'm surprised no one else has had a similar problem and seen this thread.

mr.prick
September 21st, 2008, 01:22 PM
i unhooked the 3 grounds on the back of the cylinder head
and 1 of them is open to ground and to the fuse box.
it is completely dead

joecar
September 21st, 2008, 01:22 PM
i unhooked the 3 grounds on the back of the cylinder head
and 1 of them is open to ground and to the fuse box.
it is completely dead.What color is is...? Can you identify which ground circuit it is.

mr.prick
September 21st, 2008, 01:31 PM
What color is is...? Can you identify which ground circuit it is.

LOL
it is G112 (550) and it loops to the others.
i.e. when disconnected and isolated it will be open because
it needs to be in contact with G110 to be closed.
this was a false alarm. http://smiliesftw.com/x/msn_dft001.gif (http://smiliesftw.com)

i made sure by checking the coils to it and they are closed.
all pink wires being closed to ground seems to be the issue,
unless they are supposed to be. :hihi: :bad:

mr.prick
September 21st, 2008, 02:21 PM
now that i think about it,
shouldn`t G110 (451) and 450 be open after it is unhooked from the cylinder head too?
it is closed to the main ground.:confused:
3918

mr.prick
September 23rd, 2008, 02:29 PM
i tried connecting the DMM- to the battery+ and the DMM+
to the lower fuse box and, it read battery voltage.
the upper fuse box does not.

i have checked all grounds now and the connectors look normal
and they are tight.

what is the bare minimum wires to be connected to the PCM to flash it?
i will pull all the pins that are unnecessary so i can upload a tune.

joecar
September 23rd, 2008, 04:44 PM
See "Bench Harness Wiring" near the end of post #3 in this thread: showthread.php?t=2990 (http://forum.efilive.com/showthread.php?t=2990)

joecar
September 23rd, 2008, 04:48 PM
Going back...

So, the problem(s) started after the injector install...?

Can you remember anything that may have been "suspect" during the install...?

(kinked/broken/pinched/stretched/swapped wire...?)

Did you disconnect battery anytime you removed/replaced a module connector...?

joecar
September 23rd, 2008, 04:52 PM
If you can connect the battery back on, and use DMM to measure voltage from battery POS+ terminal (wrt NEG-) all the way to the positive side of each load/device (should be very close to battery voltage... the drop should be less than 0.2 or 0.3V).

Then repeat the process measuring voltage from NEG- terminal (wrt POS+) all the way back to the negative side of each load/device (checks grounds).

If you see a large drop without cross a load/device, then you have found the problem.

mr.prick
September 23rd, 2008, 06:03 PM
i by passed all modules on the star and still could not connect.
i get less than 1 volt at the DLC (OBDII) that seems to be in range from what i`ve read.
i think it is odd that i read 12volts at the lower fuse box and it is audible to ground.
i don`t know if that is normal.
i don`t have a drain. (DMM between neg- cable and neg- battery)
no voltage drop away from the battery.

after the injector swap there were a couple instances of this but now it
seems to be permanent, this makes me think there is something broken.
all light, gauges, stereo work perfectly now with a new battery.

other than the fuse box "oddity" (if it is)
can battery cables wear out without signs of obvious wear?

i can`t get the car into the shop until next week so i have a few more days to
poke and prod.

joecar
September 24th, 2008, 03:33 AM
Cables can sometimes corrode under the insulation in the following instances:
- someone pierced the insulation to take a measurement, and then they neglected to seal the tiny hole (with paint), or they sealed it with silicone rtv (which produces ammonia over time, which corrodes the copper wire);
- moisture entered via the crimped on terminal and seeped up the copper wire stands.

joecar
September 24th, 2008, 03:38 AM
I don't like the continuity test because many loads in parallel "appear" to look like continuity to ground...

I like the voltage drop test better.

If you have a short, did any fuse pop...?

mr.prick
September 24th, 2008, 03:28 PM
well i got it to download/upload today.
also did a VATS relink,
LMAO i forgot how slow the stock PCM is to flash/read. :hihi:

once that was done i attempted to start the car to no avail.
it just cranked and the fuel pump did what its been doing. :doh2:

only "U" codes again no P1626, and after i checked the DTCs
it would not connect again and, the security light was flashing. :frown:
another strange thing, the doors would lock with the key in the ignition
even though i have option turned off.
and when locking the doors with the remote,
it would give the ring like when you try to lock the doors with the key in the ignition and not lock.
on the second try they locked. :confused:

i`m not sure what i did to get it up, other than reconnect the battery, :grin:
and why it would not start.....:chair:

joecar
September 25th, 2008, 06:46 AM
Ok, so with only PCM and tunetool on bus, you can talk to PCM... or did you "bench-harness"...?

Questions:
- do injectors fire (put finger on each one while cranking (long arms...? :D)...?
- do spark plugs fire...?

Fuel pump is cycling...?
Swap fuel pump relay with a different similar one and see if same thing happens.
Check fuel pump relay socket/wiring for bad connections.
With a fused(!!!) jumper wire, does fuel pump run...?

Your PCM may be bad... and also your BCM.

There is a way to obtain BCM DTC's... it involves removing a fuse from the LHS dash fuse panel (I have to look up which one) and cycling the ign key, and the Security light flashes a code sequence... I'll post up when I find it.

U codes mean that one or more of the modules (EBCM/ABS, SIR/airbag, IPC) can't communicate with the PCM or vice-versa.

mr.prick
September 25th, 2008, 12:05 PM
Ok, so with only PCM and tunetool on bus, you can talk to PCM... or did you "bench-harness"...?

this was through the car, for some reason it decided to "hook up"



Your PCM may be bad... and also your BCM.

i uploaded and downloaded to the PCM.
you proved the BCM does not interfere with that.
it could still be the cause of P1626
remember i am using 2 PCMs



There is a way to obtain BCM DTC's... it involves removing a fuse from the LHS dash fuse panel (I have to look up which one) and cycling the ign key, and the Security light flashes a code sequence... I'll post up when I find it.

i am definitely interested in this.



U codes mean that one or more of the modules (EBCM/ABS, SIR/airbag, IPC) can't communicate with the PCM or vice-versa.

i bypassed the IPC, EBCM and the SDM at the star and still could not
flash/read.
even after i flashed the PCM this time the car ran like poo.
there is something up with/on the class 2 comm.

joecar
September 25th, 2008, 12:20 PM
On-Board Diagnostic Features

Retrieving and Displaying DTCs

If a malfunction occurs in a system monitored by the BCM, the BCM stores a diagnostic trouble code (DTC) in memory. A current DTC means that the fault is present when the diagnostic mode was entered. Current DTCs are displayed with a beginning number 2 (2X). A history DTC means that the fault occurred sometime after the DTCs were last cleared from the BCM memory. History DTCs are displayed with a beginning number 3 (3X).

The DTCs are displayed as flash codes through the security indicator lamp on the instrument cluster when the BCM is in diagnostic mode. Perform the following steps in order to enter the BCM diagnostic mode:

1. Turn the ignition switch to the RUN position.
2. Turn the ignition switch to the OFF position.
3. Remove the Radio fuse from the I/P fuse block.
4. Turn the ignition switch to the ACCY position.
5. The BCM sounds 1 or 2 audible warning tones.
6. Within five seconds, turn the ignition switch to the OFF position and immediately (within 1 second) back to the ACCY position.
7. The BCM sounds 3 audible warning tones.

The BCM will begin flashing trouble codes using the security indicator 4 seconds after entering the diagnostic mode. Each series of quick flashes followed by a pause of the security indicator lamp on the instrument cluster represents a number in a 2 digit DTC. Each 2 digit DTC is displayed three times before the next DTC is displayed. DTCs are displayed in numerical order. Once the last DTC is displayed, the list begins again with the first DTC. This display rotation continues until the diagnostic mode is exited.

DTC Display Order

In the diagnostic mode, diagnostic trouble codes (DTCs) are displayed in the following order:

1. DTC 12
2. This indicates that the BCM is in diagnostic mode. Any current DTCs (21 to 25) then any history DTCs (31 to 35)
3. These are displayed in numerical order. The remote control door lock transmitter diagnostic DTCs (41 to 45)
4. These DTCs will display if the keyless entry transmitter buttons are pressed while in the diagnostic mode. The begin configuration display (DTC 55)
5. DTC 55 and 2 single digit configuration numbers are always displayed. The first digit following DTC 55 is the hardware configuration. The second digit is the software configuration. After the configuration numbers are displayed, the entire list is repeated beginning with DTC 12.

If only DTC 12, DTC 55 and the configuration digits are displayed when the BCM is in the diagnostic mode, the BCM has no circuit failure DTCs set and is operating properly.

If DTCs are not displayed, or if the BCM cannot enter the diagnostic mode, refer to Cannot Enter BCM Diagnostics.

If any other DTCs are displayed, refer to Diagnostic System Check - Body Control System.

Input and Output Tests

Lock Test

While in diagnostic mode, if either door lock switch is pressed, the BCM will flash the fasten seat belt indicator on the instrument cluster and sound an audible warning tone. The BCM will also attempt to perform the operation normally performed by the switch operation. In this case, as long as the system is functioning properly, the BCM will lock the doors. This is a way to test the door lock actuators, switches and associated wiring without removing the door trim or components.

Tamper Sensors Test

The BCM will also respond to a change at either shock sensor input. The tamper input is activated by minor blows to the vehicle. The shock input is activated by heavy blows. In the diagnostic mode either the tamper input or the shock input will cause the BCM to activate the horn relay, and the horns will sound. The BCM will also flash the fasten seat belt indicator on the instrument cluster and sound an audible warning tone. An effective method of checking the shock sensor and associated wiring is to tap on the shock sensor while in the diagnostic mode.

Theft Deterrent Outputs Test

Switching the interior lamps switch on and off while in the diagnostic mode will cause the BCM to flash the fasten seat belt indicator on the instrument cluster, sound an audible warning tone, and flash the courtesy lamps. On vehicles equipped with theft deterrent, each transition of the interior lamps command input will cause the BCM to proceed to the next action in the following list:

1. The courtesy lamps flash
2. The horns sound
3. The exterior lights flash

Clearing BCM DTCs

Current DTCs (21 to 25) are displayed in the diagnostic mode as long as the BCM detects the fault. Once the fault is corrected, the current DTCs are cleared by the BCM.

To clear history DTCs (31 to 35) press and hold the door unlock switch for four seconds while the BCM is in the diagnostic mode. The BCM will sound three audible warning tones to confirm that the DTCs are cleared.

To clear BCM history DTCs (31 to 35) on vehicles without power door locks, back probe the position for the door unlock signal input with a fused jumper to ground for four seconds. The BCM will sound three audible warning tones to confirm that the history DTCs have been cleared.

Leaving Diagnostic Mode

Perform the following to leave diagnostic mode:

1. Turn the ignition switch to OFF.
2. Reinstall the Radio fuse in the IP fuse panel.
3. Turn the ignition to RUN.

joecar
September 25th, 2008, 12:50 PM
Here the rest of the BCM stuff... the GM SI has it scattered around... I wonder what they were [not] thinking... it almost seems like an after-thought...

mr.prick
September 28th, 2008, 11:54 AM
i got codes 21 and 33 = shorts
i also have 26?
i can`t find 26 anywhere.


http://www.ls1tech.com/forums/images/smilies/LS1Tech/gr_devil.gif 6 6 6 th post http://www.ls1tech.com/forums/images/smilies/LS1Tech/gr_devil.gif

joecar
September 28th, 2008, 12:47 PM
I cant find 26 anywhere...

jfpilla
September 28th, 2008, 01:46 PM
P1626 Theft Deterrent System Fuel Enable Circuit

mr.prick
September 28th, 2008, 02:00 PM
P1626 Theft Deterrent System Fuel Enable Circuit

this makes sense,
though it was not on the BCM DTC list.

LOL http://smiliesftw.com/x/afro.gif (http://smiliesftw.com)
i jerry rigged an LED light between the battery neg- post and the neg- cable
and the light stays on with ALL fuses and relays removed.
looks like my DMM was right. :hihi:

jfpilla
September 28th, 2008, 02:08 PM
http://myweb.accessus.net/~090/dtcobd2.html#gmd

Try this link.

joecar
September 29th, 2008, 03:24 AM
http://myweb.accessus.net/~090/dtcobd2.html#gmd (http://myweb.accessus.net/%7E090/dtcobd2.html#gmd)

Try this link.Joe, good find...:cheers:

joecar
September 29th, 2008, 03:25 AM
this makes sense,
though it was not on the BCM DTC list.

LOL http://smiliesftw.com/x/afro.gif (http://smiliesftw.com)
i jerry rigged an LED light between the battery neg- post and the neg- cable
and the light stays on with ALL fuses and relays removed.
looks like my DMM was right. :hihi:ALL fuses (there are 3 fuse boxes)...?

You have a short between power and ground...?

jfpilla
September 29th, 2008, 12:28 PM
http://www.stengel.net/diccodes.htm

Joe,
This list at this site copies nicely to MSWord, so there's no worry about the site going away. You will have to change the font from yellow to black afer copying.
A sticky?
Joe

mr.prick
September 29th, 2008, 12:57 PM
ALL fuses (there are 3 fuse boxes)...?

You have a short between power and ground...?

i have narrowed it down to the 3 fusible links connected to the lower fuse box.
i assume this is why when all fuses where pulled the light stayed on. :hihi:
once i disconnected the lower box from batt+ and connected
the fusible link(s) directly to the batt+ the light came back on.
i am looking for a common point for the 3 fusible links.
3969

joecar
September 29th, 2008, 01:39 PM
http://www.stengel.net/diccodes.htm

Joe,
This list at this site copies nicely to MSWord, so there's no worry about the site going away. You will have to change the font from yellow to black afer copying.
A sticky?
JoeJoe,

That's handy to print out, thanks...:cheers:

I added the link, see near the bottom of post #1 (DTC's): showthread.php?t=2990 (http://forum.efilive.com/showthread.php?t=2990)

Joe

joecar
September 29th, 2008, 01:44 PM
i have narrowed it down to the 3 fusible links connected to the lower fuse box.
i assume this is why when all fuses where pulled the light stayed on. :hihi:
once i disconnected the lower box from batt+ and connected
the fusible link(s) directly to the batt+ the light came back on.
i am looking for a common point for the 3 fusible links.
3969Looks like you almost have found it...:)

mr.prick
September 29th, 2008, 01:51 PM
i just hope i don`need to pull out all 3 wires to fix it.

mr.prick
September 30th, 2008, 06:16 PM
fusible links E and/or Z are connected to the short/ground.
i unplug the fuse block junction that is under the dash,
and the light turns off but, disconnecting the fuses in the I/P fuse box
the light stays on.:confused:
when the doors are open or the key is on the light is bright,
when the doors are close or key off the light blinks.:confused:
i pulled the 4 relays under the dash, and nothing.:confused:
3977
i need more diagrams.:hihi:

joecar
October 1st, 2008, 03:19 AM
You need interior/exterior lighting diagrams...? Ok I'll get them later today.

mr.prick
October 1st, 2008, 02:37 PM
anything more related to the gauges (circuit 39)
it`s looking like i may need to start pulling wires unless there is a relay or device/module that i have not unplugged. :hihi:

joecar
October 2nd, 2008, 07:01 AM
I haven't had a chance to pull up the diagrams... I try and do it later today.

mr.prick
October 11th, 2008, 06:06 AM
i hate to continue this thread but,
after taking my car to a shop all they could tell me is that the car was dumping fuel
and that is why it won`t start.

i thought that maybe the fuel injector could be the problem and after unplugging them
i still could not connect with flashscan.
i recharged the battery some and got a connection but after awhile connection dropped.
i was only 1 volt low (11.2)
everywhere i probe i have the same voltage as the battery.

LOL i am weary about taking the car to another shop after not finding
out anything from the first one so i am back to working on it myself.

i noticed that with the key fully seated in the IGN switch the security light
does not flash with key on, with it pulled out slightly the light flashes endlessly.

joecar
October 11th, 2008, 08:18 AM
Hmmm...

Something strange is going on...

I assume the shop applied diagnostic practices/strategies...

When you take it to a shop, talk with the technician for a few moments, this will show you if they understand the importance of a diagnostic strategy.

mr.prick
October 11th, 2008, 08:33 AM
Hmmm...

Something strange is going on...

I assume the shop applied diagnostic practices/strategies...

When you take it to a shop, talk with the technician for a few moments, this will show you if they understand the importance of a diagnostic strategy.

LOL i talked to them and told them all i knew.
this was a reputable shop but, not a lot of Fbodies pass through it.
i just watched my IJBPW during cranking and it reached 122ms :confused:
i imagine that is why the car floods out before it will start.
battery volts dipped as low as 7.2
i previously thought that the car was not getting fuel because of P1626
it will start in flood clear mode the when you close the throttle fuel
continues to dump.
there is still no rhyme or reason for flashscans inability to download a tune,
though i was able to do it today.
once connection is made it does not drop until i disconnect then reconnect.
my new battery will drain down fairly quick with IGN on for awhile.

joecar
October 11th, 2008, 09:37 AM
...
my new battery will drain down fairly quick with IGN on for awhile.
There is a short or high load somewhere.

mr.prick
October 11th, 2008, 11:19 AM
my next step is to go to an automotive electrician,
i just know a GM dealer will tell me i need a new PCM. :hihi:

i think i figured out the extreme IBPW,
when cranking the volts dip to 7 volts, in turn putting me into
a higher offset in {B3701}.

if only i could flash the PCM to check my theory. :doh2:
what is the max voltage drop i should see with the key on?

joecar
October 11th, 2008, 05:22 PM
With a good battery at full charge, good power/ground connections, and a good starter, the battery voltage should drop no lower than 9.5 volts during cranking.

mr.prick
October 12th, 2008, 05:14 AM
what happened to posting up an interior schematic Joe?

joecar
October 12th, 2008, 08:51 AM
Oh, I'm having problems with my GM eSI... when I start it, it jyst spins forever... apparently the Apache/Tomcat server doesn't want to run anymore on my PC, I'm clueless so I'm going to have to reinstall, I need a few more days... I'm sorry about that...

You have a 2002 Camaro, right...?

mr.prick
October 12th, 2008, 02:17 PM
Oh, I'm having problems with my GM eSI... when I start it, it jyst spins forever... apparently the Apache/Tomcat server doesn't want to run anymore on my PC, I'm clueless so I'm going to have to reinstall, I need a few more days... I'm sorry about that...

You have a 2002 Camaro, right...?
thanks for all the help.
yes, it`s a 2002 Camaro.

when hooking up the test light the draw seems to be on the pwr accy circuit.
with the doors closed and key off the light is very dim and pulses, and the fuel level gauge jumps ever so slightly.
i unplugged a few things to no avail, i know that circuit is linked to the IPC
which is on the class 2 serial so, maybe that is what is up.

when cranking volts drop to 7-8 and IBPW shoots to 122ms. :shock:
i dropped the pulse width offset in {B3701} thinking it might have an affect
but still IBPW is 122ms cranking.
that`s like 35% duty cycle while cranking. :frown:

joecar
October 14th, 2008, 03:46 AM
Ok, I got eSi 2003 running...:thumb_yello:

mr.prick
October 14th, 2008, 02:14 PM
Ok, I got eSi 2003 running...:thumb_yello:

thanks Joecar.

beaukz28
October 14th, 2008, 02:47 PM
I'm one of those dealership techs everyone seems to be unsure about. But I do a lot of driveability. Especially on camaros and vettes. Let me see if I can help. First, the facts. You replaced the injectors now car wont start. When you go WOT it starts but loaded with fuel. Now, as said before you go into clear flood mode and no fuel is injected and it then starts. The only question I have is why did you replace the injectors. I think you all have been chasing electrial problems that do not exist (you may have created some by tearing through things though.) If the car will not start since the injectors then you have an injector or installation problem!! If it starts under WOT the the PCM and its connections are fine!! Your miscellanous codes are from running the battery low while cranking and the engine running rough when it does start. And probably some from when you were testing things. Hopefully you didn't ruin things while testing. I would bet a weeks pay that you put the wrong injectors in it. Wheather they were packaged wrong or you ordered too big injectors for your application. But if the car ran fine and you put injectors in it now it is way too rich to start than there is an injector problem. Did you put low or high impedence injectors in?

joecar
October 14th, 2008, 04:41 PM
beaukz28, welcome...:cheers:

I hope you don't mind us asking you driveability questions occassionally (how do you cure LS1 pinging...?)...:cheers:

mr.prick
October 14th, 2008, 05:34 PM
I'm one of those dealership techs everyone seems to be unsure about. But I do a lot of driveability. Especially on camaros and vettes. Let me see if I can help. First, the facts. You replaced the injectors now car wont start. When you go WOT it starts but loaded with fuel. Now, as said before you go into clear flood mode and no fuel is injected and it then starts. The only question I have is why did you replace the injectors. I think you all have been chasing electrial problems that do not exist (you may have created some by tearing through things though.) If the car will not start since the injectors then you have an injector or installation problem!! If it starts under WOT the the PCM and its connections are fine!! Your miscellanous codes are from running the battery low while cranking and the engine running rough when it does start. And probably some from when you were testing things. Hopefully you didn't ruin things while testing. I would bet a weeks pay that you put the wrong injectors in it. Wheather they were packaged wrong or you ordered too big injectors for your application. But if the car ran fine and you put injectors in it now it is way too rich to start than there is an injector problem. Did you put low or high impedence injectors in?
:grin:
actually yes i did put larger injectors in, adjusted the IFR table
and drove around for about a week making adjustments to the other injector tables, with fairly no problems to speak of.
thanks to my trusty RR and V2 AFR was spot on
except for a slight rich deceleration.

this started a while after the install not immediately, and
this problem was intermittent (it happened 2 or 3 time before)
for some reason i was able to get the car to start and run again.

can tell me why the fuel pump turns off then back on
after cranking or when the engine shut down?

beaukz28
October 15th, 2008, 07:47 AM
I can try to answer whatever you give me. Let me do a little more thinking on the fuel problem and get back to you. Thanks for clearing those things up. As for the pinging. I've seen several things cause this. It seems to be worse on the trucks and tahoes around the 2000 modle year. There was a GM bulletin to replace the knock sensors and harness. They would corrode down in the bore of the sensors from getting water down in there. Water will run down in from the back. Mostly on vehicles that were pressure washed alot. Also they had you put rtv around the holes to make the water run around them. That is the only thing that gm has. Now i've had vehicles that got a fuel filter every 10k miles or they would start to ping. Also use a good filter. No cheep aftermarket stuff. Also getting rid of the platnum (100k) plugs and going to a coolder regular style plug will help. And the last thing is the fuel pump. Pressures will be fine but sometimes they just don't supply enough volume. Especially with mods. Some people push a lot of hp on the stock pump, but I have seen them cause this for the volume problem. Hoped I helped.

beaukz28
October 15th, 2008, 08:06 AM
As far as I know, GM has always primed the fuel system before cranking and after the vehicle is shut off. This is normal. I'm not sure what kind of car you have but if it has an egr valve make sure it isn't stuck open. This will cause your concern. Also make sure your fuel pressure isn't bleeding off. After it primes it should drop approx. 5-10 psi and pretty much hold steady.

mr.prick
November 6th, 2008, 01:28 PM
can someone give me an opinion on this log.
4222

IBPW cuts out under throttle.

swingtan
November 6th, 2008, 01:40 PM
It looks like every time you leave the idle tables, it looses all fueling control.

mr.prick
November 6th, 2008, 02:59 PM
yes,
the injectors just drop off when the throttle is touched.