intermittent codes 16,36,41, and 42 :(
08-11-2005, 04:14 PM
#1
Registered User
Thread Starter
Join Date: Oct 2003
Posts: 27
intermittent codes 16,36,41, and 42 :(
Ok, I'm going crazy here.. Yes, I've searched and found lots of helpful troubleshooting information, but it's hard to reproduce the problem, so it seems like all of the troubleshooting steps check out good.. The car will run great sometimes, and then it will suddenly die, or if it doesn't die, the car cuts out for a second and then kicks back in, usually setting off a few trouble codes (16,36,41,42, but not always all of them).. I notice the RPM guage dies during this problem too, instantly dropping to 0 RPM even though the engine is still decelerating. The other thing it does sometimes, which almost left me stranded the other day, is when I go to start it, you can hear one cylinder fired, but then nothing after that.. Engine turns over, but won't start.. Then, after some random length of time, it decides to start right up..
I just replaced the opti with a brand new one from Jason Kromer a couple of months ago, which eliminated a high-RPM misfire that I was having, so I doubt that is the problem, but I guess anything is possible.. I also changed the ICM a few months before that (trying to find the high-RPM misfire).. BUT, when I was stranded the other day, I found out that some loose electrical tape had gotten under the valve cover (probably from last time I adjusted valves) and was getting oil all over the coil/ICM wiring, including a bunch of oil inside the ICM connector. I thought this was my problem, so I cleaned everything out, put new dielectric grease in the ICM connector, and the car seemed to run great after that.. I drove it approximately 100 miles with no problems at all.. Then, after it sat in my driveway for the last few days without being driven, I went to start it up today and it did the one cylinder fire and nothing after that.. It ended up starting, runs very smooth sometimes (smoother than normal it seems), but then has all of the random issues listed above.
The only other issue this car has, which may or may not be related, is that it stumbles a little bit when trying to rev it from an idle, sometimes backfiring out the intake.. I just noticed today that this issue seems to be coming and going while trying to diagnose this stupid ignition problem.. Sometimes it seems really smooth, other times it seems rough..
Any suggestions or ideas are greatly appreciated.
Thanks,
Shawn
I just replaced the opti with a brand new one from Jason Kromer a couple of months ago, which eliminated a high-RPM misfire that I was having, so I doubt that is the problem, but I guess anything is possible.. I also changed the ICM a few months before that (trying to find the high-RPM misfire).. BUT, when I was stranded the other day, I found out that some loose electrical tape had gotten under the valve cover (probably from last time I adjusted valves) and was getting oil all over the coil/ICM wiring, including a bunch of oil inside the ICM connector. I thought this was my problem, so I cleaned everything out, put new dielectric grease in the ICM connector, and the car seemed to run great after that.. I drove it approximately 100 miles with no problems at all.. Then, after it sat in my driveway for the last few days without being driven, I went to start it up today and it did the one cylinder fire and nothing after that.. It ended up starting, runs very smooth sometimes (smoother than normal it seems), but then has all of the random issues listed above.
The only other issue this car has, which may or may not be related, is that it stumbles a little bit when trying to rev it from an idle, sometimes backfiring out the intake.. I just noticed today that this issue seems to be coming and going while trying to diagnose this stupid ignition problem.. Sometimes it seems really smooth, other times it seems rough..
Any suggestions or ideas are greatly appreciated.
Thanks,
Shawn
08-13-2005, 06:26 AM
#2
Registered User
Join Date: May 2003
Posts: 2,275
Re: intermittent codes 16,36,41, and 42 :(
I saw you didn't get an answer for 2 days and thought I would chime in.
You may or may not know what the codes are so let me say anyway that 16 and 36 are the feedback signals from the opti to the PCM. 16 is low res and 36 is high res. Usually there are 2 causes for this problem, wiring or opti. As far as wiring goes, there are 3 sets of connectors the signals have to go through. 1 is at the opti, another about 3 feet away from the opti and the third at the PCM. I know the one on the opti is a B!@CH to get to but all 3 connectors should be looked at. It wouldn't hurt to ohm the wires from PCM to opti connector as well as visually checking them.
Assuming you have an OBDI (I have and you didn't mention) the 4 wires between the opti and PCM are on the Black PCM connector. They are Pink/black, Red, purple/white and red/black. Once you have ohmed from one end of the harness to the other. Plug the PCM end back in, turn the key on and measure the other end of the harness that plugs into the opti for DC voltage. Check the voltage from the pink/black wire to the red wire for 4-6 volts DC.
If that looks ok, turn the power off, and plug the opti back in. Now measure at the middle connector (about 3 feet from the opti) for the presence of feedback signals. You will leave all the connectors plugged in and will have to back probe the center connector with something like a paper clip. Turn the power on and measure between the pink/black wire and the red/black wire for 4 to 6 volts DC. If you are getting less than 4 volts, tap the key to crank the engine over for just a split second to change the position of the crank. Just a real quick tap. Now measure the pink/black to red/black again for 4-6 VDC. If it's still low, try it one more time (quick tap of the key). If it's still low, the opti is dead. Or more specifically, the optical encoders inside the opti are DOA.
After that problem is dealt with, you can check into the DTC 41 and 42 which has to deal with the firing of the ICM from the PCM. That is on the white wire from the PCM to the ICM on the black PCM connector also. When the engine is being cranked, this wire should show 1 to 4 volts AC to ground. But that's last after the feedback signals are dealt with. I think your oil leak problem is what is causing this trouble.
Just post if you have any more questions.
Good luck
Dave
You may or may not know what the codes are so let me say anyway that 16 and 36 are the feedback signals from the opti to the PCM. 16 is low res and 36 is high res. Usually there are 2 causes for this problem, wiring or opti. As far as wiring goes, there are 3 sets of connectors the signals have to go through. 1 is at the opti, another about 3 feet away from the opti and the third at the PCM. I know the one on the opti is a B!@CH to get to but all 3 connectors should be looked at. It wouldn't hurt to ohm the wires from PCM to opti connector as well as visually checking them.
Assuming you have an OBDI (I have and you didn't mention) the 4 wires between the opti and PCM are on the Black PCM connector. They are Pink/black, Red, purple/white and red/black. Once you have ohmed from one end of the harness to the other. Plug the PCM end back in, turn the key on and measure the other end of the harness that plugs into the opti for DC voltage. Check the voltage from the pink/black wire to the red wire for 4-6 volts DC.
If that looks ok, turn the power off, and plug the opti back in. Now measure at the middle connector (about 3 feet from the opti) for the presence of feedback signals. You will leave all the connectors plugged in and will have to back probe the center connector with something like a paper clip. Turn the power on and measure between the pink/black wire and the red/black wire for 4 to 6 volts DC. If you are getting less than 4 volts, tap the key to crank the engine over for just a split second to change the position of the crank. Just a real quick tap. Now measure the pink/black to red/black again for 4-6 VDC. If it's still low, try it one more time (quick tap of the key). If it's still low, the opti is dead. Or more specifically, the optical encoders inside the opti are DOA.
After that problem is dealt with, you can check into the DTC 41 and 42 which has to deal with the firing of the ICM from the PCM. That is on the white wire from the PCM to the ICM on the black PCM connector also. When the engine is being cranked, this wire should show 1 to 4 volts AC to ground. But that's last after the feedback signals are dealt with. I think your oil leak problem is what is causing this trouble.
Just post if you have any more questions.
Good luck
Dave
Last edited by slopokrodrigez; 08-13-2005 at 06:29 AM.
08-14-2005, 03:07 PM
#3
Registered User
Thread Starter
Join Date: Oct 2003
Posts: 27
Re: intermittent codes 16,36,41, and 42 :(
Dave,
Thanks a ton for the reply!
I wish I had such a good troubleshooting explanation on hand a week or two ago, but I have been trying to use the guide on shoebox's site along with some various info found in other threads, which helped alot but not enough I guess.. The frustrating part is that everything seems to check out good, but the problem is very intermittent, so it's hard as hell to even catch it when the problem is occuring.
Once I finally posted on here asking for help, I forwarded this thread to Ion (madz28) to see if he had any idea, since he has helped me with a few other issues in the past and also does the tuning. He feels certain that the problem is with my PCM and the home socket job that I did to it 6+ months ago (a detail I forgot to mention when posting here). So, I opened the PCM back up and checked out my soldering as good as I could (did ohm tests) and found nothing wrong, but there were a few points that I couldn't test, so who knows.. I didn't want to believe it was the PCM, so I swapped out my ICM to make sure that wasn't it, but no luck there. I also tested the white wire going from ICM to PCM to make sure that wasn't a problem, and it showed around 1 ohm of resistance, so it must be good.. At that point I said screw it, Ion must be right again
Unfortunately though, it seems that I've been trying to troubleshoot this backwards from how you described, mainly because of how difficult it is to get to that opti plug and also the lack of good troubleshooting info. Not to mention I just replaced that opti a couple months ago.. Anything is possible though, and I really should have started the troubleshooting at the opti to make sure the signals were working..
Anyhow, I have a local salvage yard getting me a PCM on Monday for $75 and also planned to send Ion my current PCM and have him re-socket it correctly, but I should know for sure on Monday if the PCM is the problem or not.. If it isn't, then it MUST be the opti or the wiring between it and the PCM
Oh ya, it's a 94 OBDI, sorry about that
Thanks again,
Shawn
Thanks a ton for the reply!
I wish I had such a good troubleshooting explanation on hand a week or two ago, but I have been trying to use the guide on shoebox's site along with some various info found in other threads, which helped alot but not enough I guess.. The frustrating part is that everything seems to check out good, but the problem is very intermittent, so it's hard as hell to even catch it when the problem is occuring.
Once I finally posted on here asking for help, I forwarded this thread to Ion (madz28) to see if he had any idea, since he has helped me with a few other issues in the past and also does the tuning. He feels certain that the problem is with my PCM and the home socket job that I did to it 6+ months ago (a detail I forgot to mention when posting here). So, I opened the PCM back up and checked out my soldering as good as I could (did ohm tests) and found nothing wrong, but there were a few points that I couldn't test, so who knows.. I didn't want to believe it was the PCM, so I swapped out my ICM to make sure that wasn't it, but no luck there. I also tested the white wire going from ICM to PCM to make sure that wasn't a problem, and it showed around 1 ohm of resistance, so it must be good.. At that point I said screw it, Ion must be right again
Unfortunately though, it seems that I've been trying to troubleshoot this backwards from how you described, mainly because of how difficult it is to get to that opti plug and also the lack of good troubleshooting info. Not to mention I just replaced that opti a couple months ago.. Anything is possible though, and I really should have started the troubleshooting at the opti to make sure the signals were working..
Anyhow, I have a local salvage yard getting me a PCM on Monday for $75 and also planned to send Ion my current PCM and have him re-socket it correctly, but I should know for sure on Monday if the PCM is the problem or not.. If it isn't, then it MUST be the opti or the wiring between it and the PCM
Oh ya, it's a 94 OBDI, sorry about that
Thanks again,
Shawn
08-18-2005, 03:58 PM
#4
Registered User
Thread Starter
Join Date: Oct 2003
Posts: 27
Re: intermittent codes 16,36,41, and 42 :(
Ok, it turns out that the PCM was not bad because the replacement is doing the same thing.. I just did an ohm check from the opti end of the harness to the PCM end and all wires are good.. I did find some oil in and around the opti connector, which is probably not good..
So, I was doing your next troubleshooting test, which was to check for 4-6 VDC at the opti end of the harness while the PCM is plugged in and key is on.. The first issue I came across is that my wire colors didn't quite match up with the ones you listed.. All are the same except I don't have a red wire, but I do have a yellow wire.. I assumed this was the same as your red wire, so I tested for DC volts between the Pink/Black wire and the Yellow wire and got 11.73 VDC.. I figured that must not be right, so I decided to test the Pink/Black and the Purple/White and sure enough, I got 4.99 VDC.. I was about to move onto the next test, but decided to probe the Pink/Black and Red/Black before plugging back into the opti and ended up getting 4.99 VDC there too? This doesn't make sense, since I see that your next test is to plug the opti back in and back probe at the middle connector to the Pink/Black and Red/Black to test for 4-6 VDC.. If I already have 4-6 VDC without the opti plugged in, then won't I still have that voltage when I do plug the opti in? I guess I'll go out and test that now, but does all of this sound normal to you?
Thanks,
Shawn
So, I was doing your next troubleshooting test, which was to check for 4-6 VDC at the opti end of the harness while the PCM is plugged in and key is on.. The first issue I came across is that my wire colors didn't quite match up with the ones you listed.. All are the same except I don't have a red wire, but I do have a yellow wire.. I assumed this was the same as your red wire, so I tested for DC volts between the Pink/Black wire and the Yellow wire and got 11.73 VDC.. I figured that must not be right, so I decided to test the Pink/Black and the Purple/White and sure enough, I got 4.99 VDC.. I was about to move onto the next test, but decided to probe the Pink/Black and Red/Black before plugging back into the opti and ended up getting 4.99 VDC there too? This doesn't make sense, since I see that your next test is to plug the opti back in and back probe at the middle connector to the Pink/Black and Red/Black to test for 4-6 VDC.. If I already have 4-6 VDC without the opti plugged in, then won't I still have that voltage when I do plug the opti in? I guess I'll go out and test that now, but does all of this sound normal to you?
Thanks,
Shawn
Thread
Thread Starter
Forum
Replies
Last Post