crank relearn

[odd boy]

Guys,

I installed 03' LS1 engine on an old car, I also upgraded the PCM to 03' operating system (12225074). I can't do crank relearn, and the car doesn't move right and the timing fluctuates from 9 to 22 in idle.
The trans is an old one and not connected to the pcm, and the OS is set for manual in order to avoid any cal confusion.

Do you think that the crank relearn will cause this problem? if not, would you tell me what would cause the timing to play that much??? And is there any thing can relearn the crank angle manually?

[Tordne]

That OS was used in the Holden Commodore vehicles. If you're using it on a Camaro (just from looking at your avatar) then you should use OS # 12212156 instead. There is some operating system specific code (which cannot be changed) which might cause issues.

[odd boy]

The engine is for commodore. can u help me to resolve the timing issue??

[Tordne]

There could be so many causes for timing. As you are no doubt aware looking at the calibration there are many tables which add/subtract timing based on various conditions:
- IAT/ECT Temps
- RPM deviation from desired idle
- Spark smoothing

Best bet is probably to log a bunch of spark related PIDs and see if you can derive which of them is contributing the the fluctuation.

[odd boy]

- RPM deviation from desired idle


what would cause that? what will hapen if the C.A.S.E is not relearned? will it affect the car performance or it won't find misfire if there is any?????

[joecar]

CASE is used for misfire detection... it shouldn't affect engine performance... something else is wrong, but you should see if you can do a CASE relearn anyway.

[Blacky]

When you see timing swinging at idle, usually it is a response to some other issue, not the cause. The PCM will adjust the timing (a lot) to try to stabilize the idle at the desired idle setting(s).

Something as simple as a blocked fuel filter/injector (or anything that can cause fuel delivery problems) can cause the idle to change and therefor cause the PCM to drastically alter timing to try to correct the problem.
Running too lean at idle will cause surging.

Have you tried programming in a 100% stock tune?

Is the engine modified? Different cam? Different intake? Still using a MAF? Is the IAT sensor connected and working?

Are there any trouble codes set? Have you disabled any trouble codes?
What are the test results for "specifically monitored systems"?
What are you fuel trims at idle? Are they similar for both banks?

Regards
Paul

[Tordne]

Also too much airflow at idle might be making the idle race a bit and the spark will fluctuate to try and compensate. Logging the spark PIDs might allow you to determine which of the spark modifiers is being invoked.

[odd boy]

Something as simple as a blocked fuel filter/injector (or anything that can cause fuel delivery problems) can cause the idle to change and therefor cause the PCM to drastically alter timing to try to correct the problem.
Running too lean at idle will cause surging.

new filter, injectors, and fuel pump were installed recently, I'll check the fuel pressure in order to clear up the doubt


Have you tried programming in a 100% stock tune?

The engine is 2003 (we name it Caprice here in the middle east) has the same engine of commodore but the body of the car is bigger. The PCM I've got is for the same car but 2000, I installed the stock tuning file of commodore 2003


Is the engine modified? Different cam? Different intake? Still using a MAF? Is the IAT sensor connected and working?


it is stock engine, and the MAF is there and doesn't make any deference, I keep it or remove it the car does the same. The IAT is there and working.



Are there any trouble codes set?

yes there is one for low pressure, which i guess has nothing to do with this case. Before installing OS of 2003, the MAF P0102 was on while the and its cables were checked and found okay



Have you disabled any trouble codes?

nope



What are the test results for "specifically monitored systems"?


I guess you mean cyl test, some times cyl 6 is week.



What are you fuel trims at idle? Are they similar for both banks?

I disable them, since I want the car to be in open loop all the time.

You know when I press the accelerator fully or partially at idle or while driving, the car gets strangled and moves like a 1 cyl car

[Blacky]

You know when I press the accelerator fully or partially at idle or while driving, the car gets strangled and moves like a 1 cyl car

Can you please log the following PIDs:

SAE.TP
SAE.RPM
SAE.MAP
SAE.MAF
SAE.IAT
SAE.ECT
SAE.SPARKADV
GM.AFR
GM.IBPW1
GM.IBPW2
GM.DYNCYLAIR
GM.CYLAIR_DMA
GM.EST_IAC_DMA
GM.EST_ECT_DMA

Get engine to operating temperature (about 85 degC ECT or above). Stat logging, leave it at idle for about 5-10 seconds, then slowly increase the throttle position to about 20-30% over about 5 seconds, then let it return to idle for about 5-10 seconds. Stop logging.

Then post the *.efi log file in this thread.

Regards
Paul

[odd boy]

here it is. I have some additional information for you, the actual AFR is 17.5!!!!. I multiplied by 1.23 = 17.5/14.63 but nothing happened, then I put back as it was.

Note that the log file here is for the stock one when the AFR is 17.5.


3804

[Blacky]

Are you saying the measured AFR (using a wide band) was 17.5?

If the PCM is commanding 14.63 (as per the log file) and the result is 17.5, then the engine is either getting too much un-metered air (i.e. intake manifold leak or exhaust leak) or the engine is not get less fuel than the PCM "thinks" it is delivering Possibly one or more blocked injectors or injectors that are not flowing what they say they are.

P.S. The jagged spark data is exactly what I would expect when the PCM trying to maintain constant idle under difficult circumstances (i.e. starved of fuel).

If you want to see how badly the engine runs without the PCM using the spark to control the idle, set tables: B5935, and B5936 to zero.
You will most likely find that the idle speed hunts up and down over ever increasing rpm ranges until finally it gets too low and stalls.

Regards
Paul

[odd boy]

Are you saying the measured AFR (using a wide band) was 17.5?

yes that is right


If the PCM is commanding 14.63 (as per the log file) and the result is 17.5, then the engine is either getting too much un-metered air (i.e. intake manifold leak or exhaust leak) or the engine is not get less fuel than the PCM "thinks" it is delivering Possibly one or more blocked injectors or injectors that are not flowing what they say they are.

Injectors were sent for cleaning 3 days ago and there is no difference. the headers are brand new


P.S. The jagged spark data is exactly what I would expect when the PCM trying to maintain constant idle under difficult circumstances (i.e. starved of fuel).

What is the next step? The fuel pressure was checked and found 60 Psig

[Tordne]

If you're saying that you are commanding 14.63:1 and are getting 17.5 then I think you should resolve that matter first as this is obviously of concern.

[odd boy]

I have different way to explain what is going on (I'm thinking loudly), I run the cyl test (thorough the scan tool) and I'm questioning the performance of cyl#6. Then I followed the old method of testing the performance of a cylinder/injector/coil.

I did the following:

1. I started with checking the power of the injector and the coil (by using fuse tester), the power was found okay.

2. I unplugged the power connector of the injector, very very small difference was noticed.

3. I put the connector back, but after shutting of the engine.

4. I put a new coil to make sure that the problem is not from the coil, then I started the engine and the result was "NO DIFFERENCE"

5. I unplugged the spark plug cable from the coil and again "no difference"

Do you think the cyl is week and the engine needs to be disassembled?

[joecar]

How did you use a fuse tester to check for power to injector and coil...?

What if power to either one is below battery voltage...?

A voltage drop like this (due to lose/corroded/broken connection/wire) would prevent the injector/coil firing correctly.

You have to use a DMM... there are cheap ones available for $20.


Also, to test that the injector circuit is firing, use a noid light (has the same impedance as an injector)... these are about $10.

You can feel with your finger resting on the injector that it is firing... or use a mechanics stethoscope (but you'll hear all the injectors);
problem is you can't easily tell if the spray pattern is good without removing the injector/rail assembly (and then you have to be careful not to blow up).


Also, to test for spark, use a spark tester (looks like a spark plug with a ground clamp)... these are about $25.

If spark is good, there is no need to replace the coil ($$$).


You need to do four tests before proceeding:
1. compression test: the suspect cylinder will compare lower; compression gauge is cheap $30... can tell you if it's rings or valves;
2. leakdown test: again, bad cylinder will compare lower; leakdown tester is more expensive $80+.
3. cooling system pressure test (tester is $100...goto radiator shop).
4. test for combustion gasses in coolant using a test kit $20... also observe presence of bubbles in radiator fill neck.

Those 4 tests will dictate your next actions.

If there is a problem, is it due to:
- weak spark (why?);
- weak injector spray (why?);
- insufficient airflow in/out (loose/broken rocker, bent pushrod, blockage (rag... I have seen this before)... why?);
- loss of compression (valves, springs, rings, other... why?);


Also, are you sure it is only one cylinder...?


By taking time to diagnose it, you will save time/money/effort.