Background
I'll try to keep this short but it may be hard. It may really help someone out some day. This has happened four different days over the last 5 weeks or so, usually after washing the car or it being rained on. Funny thing is that it might not be the first start after the car being wet.. maybe be the 2nd or 3rd start on the same day. Maybe just coincidence.

Symptoms
Start the car and it will either not stay running or it will run for a little bit (10-30 seconds) and then quit. When it tries to stall out, if you give it gas, nothing happens. DIC reads "low oil level". No check engine light.

Yesterday it got really bad. Car starts fine, drove one mile, shut off to get gas. Won't start again. After about 25 minutes of trying, including removing the battery cable and looking at obvious things, I got it started but it meant me stomping the gas immediately to make it come to life. It was like giving it a slap in the face. Drove 300 yards and at 20 mph in 1st gear and 25% throttle, the car bucks like traction control kicked in. Looked down and saw the "traction system activated" or some such message. I forget now, after all that's happened. Kept driving, car died in another 200 yards.

A couple attempts to start, nothing. Finally got moving again, stalled again, etc. You know the deal. Finally got it home and started researching in here. Also got some advice from Bill Curlee, who PMed me his phone number and was very helpful.

Later in the day, I decide to get brave and drive the car to see what would happen and if any codes would be thrown. Drove around, never going far from home.. no problems at all.

Later again, I decided to get really brave and make the 5-mile round trip to the autoparts store to have the battery/alternator checked and get some materials to clean the ground connections. Successful trip, no problems at all with the car. Battery/alternator checked out just fine.

I checked/cleaned 5 ground connections in the engine bay when I got home but was not able to crack into the black connectors on the grounds nearest the headlights. More on that later. I did all I could with my current inability to get the car in the air. I don't have a jack or ramps low enough yet.

Feeling pretty content with myself, given the car was running fine and not throwing codes, I decided to take the car out again this morning. First start, ran fine for 2 miles where I reached my destination. Had the car off for about 30 minutes then started again to leave for the next destination. Ran fine for about 1/2 mile. Turned on "Competition Mode" just messing around still trying to feel out the car. Stomped on the gas in 2nd gear at 40 and it fell on it's face. Went to 3rd gear and went partial throttle and it drove fine at first then fell on its face again. Hit the clutch to come to a stop at a redlight and it died. Took 3-4 tries to start it again and it cranked a good bit before it would catch.

Got it started and limped it almost home though it took some coasting and restarting. Tried to roll start it once and it started but would, again, not react to me giving it any gas. Still no check engine light or any codes at this point. No "low oil level" message either. This was the first time I did NOT see that message when this problem has happened.

Got to a parking lot down a big hill from my apartment. Me and a buddy tried the following things:

1. Unplugged the MAF and started it. It behaved the same way, wouldn't stay started and wouldn't react to the gas pedal being pressed. Threw 3 codes though I didn't get them all. I know I saw "reduced engine power" and something about traction control I believe.
2. Pulled the intake off at the thottle body and examined for any water or anything. Though the filter was a little wet on the outside, nothing else was out of the ordinary. Put it back on, started engine, same thing.
3. Unhooked the neg. battery cable. Rechecked all 5 grounds I had messed with before. This time we got into the connectors. My buddy had a pocket knife which worked better to pry than my flathead screwdriver from the day before. Both connectors (one on each side of the frame, behind the headlights) looked fine. No corrosion or anything. For good measure, we used a steel brush on them a bit. Put it all back together and started the car. Battery had been disconnected about 25 minutes I guess.

This time the car starts, still has a check engine light and two codes. PCM p1514h and TCS c1278h. Let it idle for a bit and decided to circle the parking lot a few times. Car seemed to run fine. Traction control even successfully kicked in once with a 1st gear punch in a little gravel. So we got brave and decided to attempt the 100-foot hill climb to my apartment. Surprisingly, we made it all the way in one attempt. No stalling, bucking, no new codes, etc.

So now it's home and here I am researching. Here's what I know that may affect the diagnosis.

1. I have fixed the infamous door panel wire issue. My window buttons quit working and I fixed that about 5 weeks ago with liquid electrical tape. Have worked ever since. Also fixed the passenger side but I did notice yesterday that one wire was still slightly exposed. This did not seem to affect our testing as we started the car with the wire pulled out (not possibly grounding to the car) and it did not affect anything.
2. Only 5 of 13 grounds have been checked. The 5 most easily accessible from the engine bay. Two behind headlights, one under battery, one high up on the passengers side of the engine, one on the frame slightly under the engine on the drivers side (it has one braided wire grounded to it).
3. I know I have one set of wires that have been partially melted by the passengers side header. They had been rubbing until about 5 weeks ago when we zip-tied them out of the way. They run very close to the starter. Not completely sure of their purpose?

Sorry this was so long but it's honestly about as little as I could say to give the whole story There are tons of threads out here with similar problems but I can't seem to find one case EXACTLY like mine.

 

You have a weird problem for sure.
Minus 3/4 of your situation and i would have guessed fuel pump going bad.
Sorry i cant help

 

I agree. I thought about that yesterday as well. The weird messages and sporadic behavior make me think it's electrical, though.

 

Check those wires that melted befor. Find a way to get under the car and look up.
Goood luck

 

First thing I'd do, since you mention water (washing and rain) is check under the carpeting in the passenger footwell, is it wet/damp ??? It is possible you have a plugged drain in the cowl and the water is getting into the area where the BCM is located.

 

Yeah, I agree for sure. I'm going to invest in a low-profile jack and/or get some boards to drive up on to get a regular jack under there. Those wires and all the other grounds are first on my list to check. Just haven't made it that far yet, been busy watching all my friends run at the dragstrip all day while I missed my Z06

 

I looked under there yesterday and everything looked good and dry. I admit that it's worth another more thorough look, though. The dampness is a coincidence that I can't completely get out of my mind, though I would expect it to cause problems on the FIRST start after I washed the car or it was rained on. For the four events this has happened, all hell broke loose starting with the 2nd start, 4th start, 2nd start, 2nd start. I guess you never know where water might get stuck and roll around, though.

 

What about maybe the column lock issue. I have heard of issues with that even after doing the column lock recall. I think there is a resistor that causes problems with this. With the resistor being bad the car thinks the column is locked and when you start to drive it shuts the car down.

 

Maybe have found the answer. This thread is very similar to mine.

http://forums.corvetteforum.com/show...d+engine+power

 

I agree, Camaro SS. My friend John (you ) just told me about that one. Check out what I just found, man.

 

Scott, there are two grounds in the rear wheel wells. You can see them in the upper rear quadrant inboard of the tire. One has something to do with traction control - clean them being careful not to snap them off! (lots of WD40).
Scary part is that you have been to the mountain (BILL CURRY) without success. Bill is among the best and if he can't help you, euthanasia my be your only recourse.

Seriously though, you need to write down, then clear all the codes you get. There's gotta be more than two with all your problems. See which ones recur after the next incident and we'll have a start. If it's the PCM it is still covered if you have less than 80k miles on the car.

Codes:
http://www.stengel.net/diccodes.htm

 

Thanks for chiming in, Vince. John told me to contact you about this and I just hadn't found the chance to yet. I'll check those grounds when I get to fixing that partially melted harness. By the way, that was Bill's #1 suggestion as to what might be wrong when I spoke with him on the phone Saturday (melted wires/harness).

Nope, those are all the codes I had. On Saturday when all this first started, there were a bunch of codes but I cleared them all, thinking maybe they were very old. I would say I had about 10, in various categories.

One question I have, when you pull the battery cable, do the codes even in the history clear out?

 

Scott, I don't think disconnecting the battery clears any codes, but I could be wrong. I know how frustrating these kinds of problems can be. It took 3 flatbeds to the dealer till they finally replaced the PCM on my wifes '99 - been fine ever since.

 

Too early to tell with a ton of confidence yet but the car *may* be fixed now. Got some help from a buddy that works with car electronics by profession. The car drove just fine for the 5 miles to his shop. Got it up on the lift and checked things over. The harness going to the passenger O2 sensor was the bad one. It had sat on the header at some point and partially melted the wires and the plastic plug. There was exposed wire and a good bit of corrosion inside the plug itself. I still don't understand why this could cause problems like I had but if it worked for other people then maybe it will for me too. Anyway, he soldered the wires together (yes I realize if I have to replace that O2 sensor then they get cut again ) It was a quick and easy fix this way. We added some heat shielding and tied them up and out of the way of the header.

While he worked on that, I checked for more grounds to clean. Vince, I only found a ground in the back on the driver's side. The stud on the passenger's side had nothing grounded to it and, in fact, was covered with like a piece of vacuum line. It didn't look factory and struck me as being kind of odd. Any info on this is appreciated. That one ground was the only other one I could find. I looked all over the place but didn't go as far as the remove anything (like the torque tube ).

I also removed the battery to check for a possible leak and looked in the passenger floorboard again for any signs of leaks. Everything checked out just fine.

So we took it out for a test drive, about 3 miles. I tried everything I could think of that made it go bad this past weekend and it never failed once and threw no codes. Dropped him back off at the shop and drove 5 miles home, also with no troubles and no codes.

I definitely don't feel 100% like it's fixed, it will take some time to sink in. I want to see what happens in the rain, since it still makes me think moisture was related to my problem. However, it worked at least for the person with the thread I linked before.. maybe it worked for me too?

Does this make sense to anyone that the passenger O2 harness being partially melted (but not currently touching the header) could cause all these problems? Stalling, not starting, traction system kick in for no reason, "low oil level", check engine codes, etc.

 

Look on the bright side; everything you do narrows down the possibilities towards a fix.

Keep a record of everything you did such as what grounds and connectors you have verified as good, etc.

Cleaning all the grounds & other connectors as you go along can head off future electrical anomalies.

For all reading this:

Remember, when checking electrical connections you MUST take the connection apart and carefully inspect each and every pin for tightness and freedom from corrosion. (Some will simply LOOK at the outside of the connector, wiggle it a little, and assume the inside is clean and tight if the outside appears clean)

 

Yeah, that's the bright side for sure. My next idea is looking at the MAF for oil/water and checking the throttle position sensor, per cenzo's advice.

On a side note, I also checked the oil level sensor last night and it seemed kind of loose. It pulled right out of the plug without prying on the tab or anything. In fact, I pushed it back in a couple times before it clicked into place so I can see how it happened to whoever may have messed with it before. Remember one message I got a lot with this issue was "low oil level".

Referring to this image, courtesy of Bill Curlee, I have now checked and thoroughly cleaned grounds 101,102,104,106,107,401 and confirmed that I don't have a ground at location 402. This includes inside the plastic connectors at 101/102, though they showed no corrosion anyway.

 

When you mess with the PCM electrical signals, you will be surprised at what can happen. The O2 sensor signal wire to ground or to the O2 sensor heater voltage is NOT very condusive to a correctly running LS engine. Im sure you made major head way. You have on idea what was shorted to what. You have o start at the KNOWN damage, fix that and go from there.

G402 is only used on 97 and early 98 C5 that have rear mounted EBTCM. The stud should have the rubber cover on it. That stud makes a very good stereo chasssis ground!

BC

 

Thanks for the feedback, Bill. I hope the problem is covered. It's weird to want to drive the car to confirm it's fixed but to be afraid to drive it and maybe get stranded away from home.

 

I havent been home for a couple days to test the car out some more but I've been researching more to know what to check next if it's not fixed. I found this thread with a similar problem:

http://forums.corvetteforum.com/show...l+level+ground

G105 is one that I haven't found yet, despite a lot of looking. Does anyone have a picture or good description of where this ground is located? I also have not found 103.

 

I think this confirms G105 possibly being the problem, if fixing the melted wires didn't already fix it. First thing when I get back home Sunday, I'm finding 105.



"Low oil level" message 90% of the time when the car has this stalling & not running problem. Wires burnt on the front HO2S, they ground at the same place, makes sense to me.