P1351 ICM CirHighVoltage (seems to be unsolvable) **MERGED THREADS**
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From: Dallas, TX
P1351 ICM CirHighVoltage (seems to be unsolvable) **MERGED THREADS**
***MERGED MY THREADS***
1996 M6 Camaro Z28
Alright, I have had this problem for about 4 months now if not more, the engine itself has 20k on it, and I put it in myself. All ignition parts are brand new, heres a list of the new parts:
ICM Module
Optispark
MSD Coil
PlugsPlug Wires
MAP Sensor
CKP (replaced when engine was built)
Optispark Wire Harness Connector
Eng Temp Sensor
The car has alot of vibration when running (from the stumbling at all rpms) and basically runs like crap and backfires/misfires horribly, doesnt overheat or nothin like that, but when I floor it, doesnt wanna go rite away and will pickup some but the rpm's dont climb quick like they use too. I have 2 96/T-56 PCM's and 1 is stock with stock knock module and the other is tuned for the 360ci LT1 (rebuilt to this 388) and has LT4 knock module. Timing chain is the only other concern, was on the motor when I got the car, had 15k, was used in the 360 for about 20k and is currently used in this motor for 20k so far, so a total of about 60k on the chain. I spun the crank hub off not too long ago and had to put a helicoil in the crank and buy a new aftermarket keyed hub from Powerbond I belive it was.
Recent info: Had the car scanned, it has only the P1351 present now, replaced the wiring harness with one I got from a local guy, everything was in tact, low mileage, all connectors were there. Now I know its 1 in a million if I found a harness that would have the same prob so Im going to rule that out + the guy had no problems out of it when it was pulled, the car didnt have a motor cuz he pulled it. I need to know everything related to this code, this is a battle that I dont think I will ever win. Ive gotten to the point of just replacing parts because it has stumped me. P1351 is also suppose to disable the injectors, and it shouldnt start nor run, but it does. Taken it to a couple of shops, they looked at it for awhile and still didnt know what the problem was and I basically handed them free money.
I need any and all input as to what yall would think could be causing this, I think its something else triggering it that isnt suppose to, as in a problem that is setting off the wrong code, im really leaning toward replacing the timing chain and reluctor wheel and seeing if that dont change it all. I was counting on the new harness to stop this because it was an electrical code. Thanks
1996 M6 Camaro Z28
Alright, I have had this problem for about 4 months now if not more, the engine itself has 20k on it, and I put it in myself. All ignition parts are brand new, heres a list of the new parts:
ICM Module
Optispark
MSD Coil
PlugsPlug Wires
MAP Sensor
CKP (replaced when engine was built)
Optispark Wire Harness Connector
Eng Temp Sensor
The car has alot of vibration when running (from the stumbling at all rpms) and basically runs like crap and backfires/misfires horribly, doesnt overheat or nothin like that, but when I floor it, doesnt wanna go rite away and will pickup some but the rpm's dont climb quick like they use too. I have 2 96/T-56 PCM's and 1 is stock with stock knock module and the other is tuned for the 360ci LT1 (rebuilt to this 388) and has LT4 knock module. Timing chain is the only other concern, was on the motor when I got the car, had 15k, was used in the 360 for about 20k and is currently used in this motor for 20k so far, so a total of about 60k on the chain. I spun the crank hub off not too long ago and had to put a helicoil in the crank and buy a new aftermarket keyed hub from Powerbond I belive it was.
Recent info: Had the car scanned, it has only the P1351 present now, replaced the wiring harness with one I got from a local guy, everything was in tact, low mileage, all connectors were there. Now I know its 1 in a million if I found a harness that would have the same prob so Im going to rule that out + the guy had no problems out of it when it was pulled, the car didnt have a motor cuz he pulled it. I need to know everything related to this code, this is a battle that I dont think I will ever win. Ive gotten to the point of just replacing parts because it has stumped me. P1351 is also suppose to disable the injectors, and it shouldnt start nor run, but it does. Taken it to a couple of shops, they looked at it for awhile and still didnt know what the problem was and I basically handed them free money.
I need any and all input as to what yall would think could be causing this, I think its something else triggering it that isnt suppose to, as in a problem that is setting off the wrong code, im really leaning toward replacing the timing chain and reluctor wheel and seeing if that dont change it all. I was counting on the new harness to stop this because it was an electrical code. Thanks
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Posts: 1,127
From: Dallas, TX
P0335 and P0336 are gone, due to a broken wire on the old harnesses CKP sensor connector.
These are the replies Ive had from my other thread:
These are the replies Ive had from my other thread:
Injuneer: Shoebox's list is the most accurate:
http://shbox.com/1/Dtcs.htm
P0335 = Crankshaft Position (CKP) sensor circuit
This sets when the crank sensor duty cycle is low, indicating a circuit failure.
P0336 = Crankshaft Position (CKP) sensor circuit performance
This one sets when the duty cycle on the signal is outside the acceptable range, indicating a malfunction of the sensor, loose wheel, wheel hitting the timing cover, etc.
The CKP sensor signal on the LT1 is 4X.
http://shbox.com/1/Dtcs.htm
P0335 = Crankshaft Position (CKP) sensor circuit
This sets when the crank sensor duty cycle is low, indicating a circuit failure.
P0336 = Crankshaft Position (CKP) sensor circuit performance
This one sets when the duty cycle on the signal is outside the acceptable range, indicating a malfunction of the sensor, loose wheel, wheel hitting the timing cover, etc.
The CKP sensor signal on the LT1 is 4X.
Injuneer: I'd like to know the exact relationship of the CKP to the Opti pulse pattern. The PCM uses the CKP to look for unexplained variations in crankshaft rotational velocity, which the PCM interprets as misfires. I've read that it actually compares the tiny changes in velocity from each cylinder firing to a standard pattern. The PCM can use the Opti high res signal to detect changes in crank velocity due to open and closed throttle. It needs the low res pulse to determine where the crank is, so it can assign the misfire to a specific cylinder. If the Opti high res pulse pattern is corrupt, is this enough to confuse the PCM into calculating the wrong duty cycle for the CKP sensor signal, and set the P0335/0336 codes?
shoebox: I'll paraphrase some stuff about the CKP from the "bible" (factory manual).
The PCM uses the 4x signal from the CKP to determine crankshaft velocity. This variable is used to detect misfire. The sensor is not used for spark or fueling (like we have not said this many times
. For the diagnostic the PCM monitors the CKP signal and the low and high resolution signals from the opti.
During normal operation, at the falling edge of a CKP signal pulse (signal voltage transitions to low), the PCM starts counting high resolution pulses. The counter will increase until the PCM detects the leading edge of the next low resolution pulse (voltage transitions to high). The PCM monitors the number of high resolution counts to verify the proper CKP sensor operation. [A Tech 2 or dealer scanner can display camshaft deviation and calls it "Low resolution angle" in degrees of advance or retard in relation to the crankshaft
The PCM uses the 4x signal from the CKP to determine crankshaft velocity. This variable is used to detect misfire. The sensor is not used for spark or fueling (like we have not said this many times
. For the diagnostic the PCM monitors the CKP signal and the low and high resolution signals from the opti.During normal operation, at the falling edge of a CKP signal pulse (signal voltage transitions to low), the PCM starts counting high resolution pulses. The counter will increase until the PCM detects the leading edge of the next low resolution pulse (voltage transitions to high). The PCM monitors the number of high resolution counts to verify the proper CKP sensor operation. [A Tech 2 or dealer scanner can display camshaft deviation and calls it "Low resolution angle" in degrees of advance or retard in relation to the crankshaft
gitsum: The reason i asked is because i had a bad stumble with the same code and it turned out to be the cam dowel pin was to short. But that cant be your problem.... maybe the wires on the passenger side got burnt by the headers? IIRC, the CPS is one of those wires.
moparman: The P1351 idicates a problem somewhere with the ICM. Possible high voltage due to an open circuit.
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Posts: 27,727
From: Little Rock, AR
Have you looked at every inch of the wiring from the PCM to the ICM and metered it for trouble as you moved it around? It is not perfectly clear from above that you changed the whole engine harness or just the opti harness. Have you checked the related pins on the back of the PCM?
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Joined: Jan 2006
Posts: 1,127
From: Dallas, TX
Replaced the o2's, made some homemade extensions off of the old wiring harness + old o2 sensors and hooked them up, car still runs a little rough, I can hear the miss in it and It would barely wanna go before but when i replaced them, the car broke the tires loose, and launched pretty nice on the new nittos i just got (before the car went to ****) but there's still a miss and runs rough, but were making progress, tires broke loose, good sign.
Next: Planning to pull timing cover, replace timing chain and sprockets and since im down there, messing with the opti again. I have ways of getting stuff replaced free......... thanks
Next: Planning to pull timing cover, replace timing chain and sprockets and since im down there, messing with the opti again. I have ways of getting stuff replaced free......... thanks
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Joined: Jan 2006
Posts: 1,127
From: Dallas, TX
More bad news, replaced the timing set, old chain was worn with about 1" of slack, the car started right up but still runs like straight **** and has the same code, starting to wonder what the hell is wrong with this car, if anyone could try and help me out, I will use your every idea that I can or have not tried. After replacing the o2's it did run better and a little stronger.
I am just about done with this car, only cure that seems feasable is LS1 conversion, talking Engine/Harness/Dash and all.
I am just about done with this car, only cure that seems feasable is LS1 conversion, talking Engine/Harness/Dash and all.
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Posts: 1,127
From: Dallas, TX
i was just stating that the coil was installed prior to the code, it didnt pop up at that moment, it was months down the line after install of coil, ill put stock one back on to see, but not sure if it will cure it. i think ive tried this already.
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Joined: May 2003
Posts: 6,661
From: LA (lower Alabama)
Have you got a mail order tune even?
Talk to Bryan or Ivan and see what they think,(tune up guys) They should be in the supporting vendors list.
Injuneer is really good on this type of stuff but he is time limited.
Talk to Bryan or Ivan and see what they think,(tune up guys) They should be in the supporting vendors list.
Injuneer is really good on this type of stuff but he is time limited.
Thread Starter
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Joined: Jan 2006
Posts: 1,127
From: Dallas, TX
talked to injuneer and shoebox, ive tried everything they have told me. I am already about to decide if its worth fixing or pull the motor and do a full LS1 conversion, dash and all.
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