JLZ06TR

I have been struggling with this issue for a while now. My 2002 Z06 starts up fine and runs for a while. When temps get around 150 or so it will suddenly stop running. Particularly it will read 0 rpm and stop running. Sometimes it takes a few seconds or a minute after this happens till I can crank it up again. Once I do it will run fine pretty much indefinitely until I let it sit again, completely cool down and it will happen again the next time I start it.

I thought it has to do something with it transitioning from open loop to close loop, but I am not sure how to verify this. Also I replaced the crank positioning sensor since I got a code saying that it was having slow response. While I was in there I noticed that the wires going to the crank shaft sensor were in bad shape because of my long tubes so I repaired that too. I thought all of that would do the trick but it did not. I will add though to prevent future damage to these wires i zip tied them to a ground that goes to the block. Not sure if there is enough "noise" there to mess with the Crank position sensor signal but I would think if it were an issue, it wouldn't run at all. Anyways When it shuts off suddenly like that, if i run the codes right after it happens I get P1637H.

I'd appreciate any help with this. Car is starting to feel dangerous to take out because having it suddenly shut off in traffic is not fun.

EDIT: I wanted to add that I haven't done a crank relearn with the new sensor so Ill do that and see if it helps. Also not sure if it matters but when the car is off, the DIC reads around 11.7V but when its running it reads 13.8-14.1V. Also my horn does not work.

Tulsaeasyrider

My 2002 is a convertible and not a Z06, but it had some similar problems. Just got it back yesterday with a rebuilt (there are no new ones) GM computer module (about $900) as well as a new ignition switch (about $200). You might consider these as you investigate further. It may be unrelated to your problem, but the above fix seems to have eliminated the difficulty I had in starting/restarting and the various codes it was throwing.

JLZ06TR

Yeah looking into P1637 that seems to be one course of action. I wanna try a couple other things first before replacing the PCM.

JLZ06TR

I decided to run the codes and this is what I found:

PCM:
P1637H

TCS
U1016H

SDM:
B0026HC
U1016H

LDCM:
B2282H
B2284H
B2264H
U1064H
U1016H

RDCM:
B2283H
B2285H
B2265H
U1064H
U1016H

BO-RFA:
U1000H
U1016H

I cleared them and drove around a bit and all the RDCM and LDCM codes cam back. PCM code did not.

Can anyone give me some insight?

JLZ06TR

Still having this issue and it seems to be getting worse. It now takes a while after the first shut off for it to run again. It cranks fine but it does not fire up.

Also I want to add that last time it died I left the key in the on position and the car in gear. Even though by coasting the engine was turning over, the rpm gauge was reading zero and obviously it was not running. Like I said before, I had just replaced the crank shaft position sensor believing that to be the issue. I haven't performed a crank relearn either, not sure if that matters. Any help would be appreciated.

nsogiba

I had the same issue you're describing, but replacing the crank position sensor fixed the problem. You may have a bad sensor out of the box. Also, I know you said you replaced the damaged wiring - but did you verify continuity between the pigtail and the PCM? You may have another break elsewhere in the harness.

Probably easiest to try the relearn first.

JLZ06TR

I didn't check for continuity all the way to the PCM but I did along the wires themselves where the repair was done. I think if these wires were the issue it would be more random or not run at all. But the car consistently does this. I am starting to think that something is going on when it transitions from open loop to close loop but I am not sure.

nsogiba

If you could log the crank position sensor signal with the engine running when it has the issue it'd be easy to see. Do you have access to HP Tuners or the like?

Honestly pinning the CKP wiring to the PCM is the easiest way to eliminate that as a variable. Perhaps something is heating up and grounding/moving.

JLZ06TR

I do have HP tuners. Do i need to add a new parameter to the scanner to log crank position sensor signal? what would this parameter be called?

Ill datalog it and try to upload it soon.

Thanks

nsogiba

I'm sure you could add a parameter, I just don't know which one.

You might want to post this over on LS1tech in the PCM section or the HPTuners forum for more detailed info on logging.

JLZ06TR

So I was able to datalog the event. I started with the car completely cold and in total it shut off 4 times, hence the separate datalogs. After restarting it for the 5th time it seemed to have normalized and it ran fine. Each datalog is titled for the corresponding shut off time it recorded. I personally cannot see anything that stands out. Also I should add the car is not stock, it has an aftermarket cam and heads(installed in 2014) but it was professionally tuned and it has run perfectly until recently so I don't think its the tune but I could upload that as well.

JLZ06TR

Any thoughts on this?

JLZ06TR

what symptoms exactly where you seeing?

Yokesc5

nsogiba

Initially it started as I was datalogging using HPTuners for something totally unrelated. I was idling for about 20 min playing around on the laptop when the car suddenly started stumbling and running rough (almost like it was dropping out 3-4 cylinders). Eventually it stumbled bad enough that it totally shut off and was really tough to restart. Shut it off and let it cool down for 10 min, then it restarted with no issue, but after a few minutes it would start stumbling really poorly and eventually die. I was about 5 miles from home as all this was happening. When I finally got within a block or two of my house, it hit me that I should watch what the tach was doing when it would miss and stumble. Sure enough as I was nursing it home, the tach needle would go wild and jump around when it missed (no doubt interference to the crank position sensor). It died on me again as I coasted into my uphill driveway doing 10mph. I was pissed off and just left it for the night. The next day I started it again when it was "cold" and it fired up with no problem.

Hope that helps in your diagnosis. A new crank position sensor fixed the issue for me, but if I were you I'd check the continuity of the CKP wiring to the PCM connectors with a multimeter.

JLZ06TR

So just an update, I replaced the PCM but the problem continues. I am not sure if the ignition switch could cause this issue but I tested it and only saw a very slight drop on some fuses. I am at a loss at what could be causing this so any help would be appreciated.

JLZ06TR

So I wanted to give an update and thank the guys who helped me out on this. It looks like it was the harness going to the crank position sensor. Apparently when that harness got hot something was shorting in it causing the issue, but only when it was hot. I was able to replicate the problem by poking the wires going to the crank sensor while that area was hot, but it would go away once it cooled. Anyway, I cut out the crank sensor harness as far back as I could and installed new wiring. Car is driving fine now. Thanks again.

nsogiba

Nice! Always good to get a conclusion out of it!