Help! Short log included.

[kistlerjm9]

So I was driving along and the maro just shut off. Great fuel pressure, no spark or injector pulse. Was able to flash computer, grounds all look good. So I went out to mess around with her again and she fired right up. So I logged a little bit a data and she died. Wont start again. Im thinking bad crank sensor, but if you can look at the log and see if you see anything at all. Im lost.

[joecar]

While cranking can you read RPM...?

If not, then there's no crank sensor signal (failure in the senor or the wiring to it).

Ignition and injector signals are timed from the crank sensor signal.

[kistlerjm9]

yep not able to read rpms while cranking... have voltage to the sensor, will replace in the morning and post back thanks. wasnt sure if the crank sensor control injector signal as well.

[joecar]

If you have a DMM you should see about 1 to 2 volts AC while cranking.

[kistlerjm9]

Got voltage to all 3 wires? 11.5 to the green, .4v to yellow and black and .2v to the blue. I thought one of those was a ground. I replaced the ckp sensor and same thing will run few a minutes and just shut off, no codes. Communication to the computer is still good but that is the only thing that can still be wrong. I wired the reverse lock out to the correct pin and used a diode. wonder if i still got a surge and fried the comp. Thats the only thing I touched on the computer and it works properly. IDK im about ready to burn this bitch to the ground.

[joecar]

I assume you took all measurements wrt engine ground (and while cranking)...?


dk blu/wht = signal -> 0.2V is too low (did you select V AC on the DMM)...?

lt grn = voltage reference (thru PCM) -> 11.5V is ok.

yel/bla = ground reference (thru PCM) -> 0.4V is maybe ok.

See attached wire diagram.

[kistlerjm9]

yeah those were all while cranking and for the signal sorry i get 1.2v, but i scanned again today while it wouldnt start and i get no voltage anywhere while cranking.no rpm's, no o2 voltage ect, only reading that works is throttle position and map.

[kistlerjm9]

i think the pcm is losing ground internally hence the reason for the intermitant starting. next tool, blow torch anyone.

[kistlerjm9]

well after cranking it for forever i got it to kick the code p0335 dont understand its a brand new sensor and the wiring seems fine?

[joecar]

See attached procedure.

Are you sure the wiring is fine (don't assume)...

And new sensors have been known to be bad.

Cheers,
Joe
:cheers:

[kistlerjm9]

thanks joe was just looking at that same thing from gearchatter. will run test in the morning and let you know thanks again.

[kistlerjm9]

went through the troubleshooting steps and its either a bent reluctor wheel :( or they gave me a bad crank sensor. New crank sensor will be in tomorrow. Fingers crossed. Reluctor wheel seems fine as i rotated the engine by hand and looked in the hole with a mirror. IDK thanks again joe for the help will let you know.

[kistlerjm9]

alright got new crank sensor put it in. still nothing rechecked voltage. 12 from ignition source, solid ground, but still on .4 volts while cranking from the signal. It is the same at the connector and the pcm. That is way to low should be 4 to 6 volts. Bad pcm. Will replace and let you know lol.

[joecar]

Measure AC volts at the crank sensor signal wrt ground ref with connector disconnected (while cranking)...
if you see less than 2V (or less than 4V) then reluctor and/or sensor is not working;

if you do see the right voltage, then reconnect connector, and measure again...
if you don't see the right voltage, disconnect the PCM and measure the voltage again...
if you don't see the right voltage then the wiring is shorted, else the PCM is shorted.

Be sure to measure the AC volts between dk blu/wht "signal" and yel/bla "ground ref".


I assume you took all measurements wrt engine ground (and while cranking)...?


dk blu/wht = signal -> 0.2V is too low (did you select V AC on the DMM)...?

lt grn = voltage reference (thru PCM) -> 11.5V is ok.

yel/bla = ground reference (thru PCM) -> 0.4V is maybe ok.

[kistlerjm9]

Wow pulled the o2, ckp sensor, harness up through the top. Unwrapped the loom and found three wires inserted in the ckp sensor. All soldering was corroded, massive balls of electrical tape and was 16 gauge wire. For a car with 34000 miles the previous owner must have been a complete moron. Properly fix the wires aka solder, heat shink, ect. Plugged everything back in and fire right up. What a bitch. Thanks again Joe input has been invaluable. Should have just unwrapped the loom to start.

[joecar]

Wow pulled the o2, ckp sensor, harness up through the top. Unwrapped the loom and found three wires inserted in the ckp sensor. All soldering was corroded, massive balls of electrical tape and was 16 gauge wire. For a car with 34000 miles the previous owner must have been a complete moron. Properly fix the wires aka solder, heat shink, ect. Plugged everything back in and fire right up. What a bitch. Thanks again Joe input has been invaluable. Should have just unwrapped the loom to start.He must have used acid core solder... :crash:

Now it runs, cool, good job...:cheers:

[kistlerjm9]

yeah thats exactly what it was, thanks again man. should have known something was a miss when i was getting .4 volts on a ground. im an idiot as well. :)

[joecar]

Yes, I should have seen that also...

Anything above 0.1V on a ground circuit is not acceptable.

[kistlerjm9]

well if youre ever in western pa, lmk, i owe you a few beers.

[joecar]

Ok, thanks...:cheers: