C5RUZR

iTrader: (4)

Suggested by friends from back home to post in here, so here goes:

So I get my cheery butt up bright and early (for me) @ 630 AM to make it to the local Auto-X event by the 830 registration. Rush around trying to do everything last minute because I just remembered it/decided to go @ 230 AM. So, I hit the road to make the ~1 hr drive and before I get a mile down the road I start to notice a shudder. Great, just when I want to break down! I'd started noticing it every once in a while - usually after "spirited" driving the past few days. Last night I put the car in Neutral, and ran it up to and held it at 2000RPM. Not sure if that helped or hurt my case, but that's what we do to airplane motors (yes, I know they have a mixture control and the Vette doesn't) to burn off the carbon deposits on the spark plugs. But anyways, I thought maybe I could get through it and if it was carbon it might just burn off with further driving. Fast Fw 5 minutes. Pulled over because the car keeps dying on the road. I check the plug wires, which are slightly loose connecting to the Coil packs. Managed to burn my knuckle pretty good. Car fires right up, idles nicely, I thought maybe that was it...but oh, no. So I turn around and make it home, having to restart ~5 times.

I really haven't taken the time to use "search", I'm too frustrated to think about what I should search for. I thought maybe my codes would help, but the only one I have is U 1160 H, LDC No Comm. Don't think that's hurting me..
I had an ECM Grounding issue last month that resulted in a $300 labor bill plus tow last month. Other than that, the car's been real reliable for the past year, hoping I'm not surfacing electrical gremlins.
Mods include: Kooks LT/Off road X, BB Rt66, Vararam, Hyperstat, Full Tune, GM HP (Red) plug wires, LS6 Intake minor electrical/interior stuff (LED's, etc) on a 1998 C5 Coupe ~98,000 miles

Any thoughts?
Went back to bed, disappointed to miss the event, and upset with my baby.
Started by changing the plugs for some fresh TR55's. After all, motor running right these days = compression + fuel + spark + computer. Don't see how compression is the likely culprit; maybe fuel pump of fuel filter related? And the symptoms (in the cockpit IE no lights or codes) are much different than the computer-related issue last month (though that doens't rule it out)

Old plugs didn't look terrible, only had about 3 months and 5000 miles on them. Replaced them with new TR55's, but no improvement. Car won't even idle now. Cranks hard, sometimes it'll start, sometimes it won't.
Also, now have code P1571 ASR Desired Torque -C. Cleared it, but I don't think this is the root of the problem, more like a side effect. Any thoughts!??!
Thanks guys,
Steven

Sprayed1998

iTrader: (10)

o2's maybe. ususally when cars start acting sfunny it turns out to be the o2's

LS1powerhouse02

iTrader: (9)

yah i'm thinking your 02s are going out or possibly even the fuel pump starting to go. Just my .02........good luck!

Brent

C5RUZR

iTrader: (4)

If it's o2's, and the rear's were edited out during tune, would that impact anything? Also, wouldn't I likely see codes if it's an o2 sensor problem? And if it was O2's I would think that the car would start fine, but I'm having problems even getting it to catch on the start now...

LS1powerhouse02

iTrader: (9)

when you turn your car on (don't start it) do you hear the fuel pump whine? You should be able to hear it prime.

Sprayed1998

iTrader: (10)

The o2's would explain it hesitating and stuttering, the fact that it wont idle and start sounds more like a fuel pump issue.

C5RUZR

iTrader: (4)

It's hard to remember exactly what I should hear, but I think I hear the fuel pump over the other chimes. This time the car started up once, died immediately. Started up again, died immediately. I got some gas on it, started up and it revved up for a second, then died. Now it won't turn over. Strong presence of gas odor in the car. And immediately after it dies it makes a strang "whirring noise." Lasts about 1.5 seconds, and just sounds like a medium-pitched wind down (fuel pressure being released???)

Pat7272

It wont turn over, or it will but wont start?

These last few posts are making it sound more fuel pump related, but if theres a strong odor of fuel doesnt that sound like flooding?

Also, just an idea, could bad coil packs be an issue here?

SLPformula

iTrader: (3)

Whens the last time you changed your fuel filter? Well it does sound like your fuel pump taking a shart. I think if its going bad it will pump gas for a second then it will get hot and die it. Kinda like a window motor when its going it will work for a sec then peter out cause it gets hot trying its hardest to work then dies im not really sure how to explain electrical stuff so im not so get your pump checked out.

C5RUZR

iTrader: (4)

It will turn over, but will not "start" after the fourth cycle or so. I have no idea on the fuel filter. Bought the car with 79000 miles, now at 98,000 1 year later...probably time to change it.
I was thinking flooding as well. Coilpacks came to mind earlier. I just think there'd be a misfire code, but maybe not.

This felt exactly like what happened to my mom and I on a road trip 2 year ago in the Chrysler minivan. That ended up being a bum fuel pump. I'd just really like to confirm before I spend the time and money! Thanks all
Any way to use a fuel pressure tester to confirm a pump/filter failure?

SLPformula

iTrader: (3)

You could check the pump itself by dropping the tank with a volt ohm meter. Or i think you can pull off the sending fuel line turn the car over or turn the key on and see if it pumps. First check the fuel pump relay. I havent realy worked on a vette so im not sure but what your describing sounds like a fuel pump issue. Where do you live?

C5RUZR

iTrader: (4)

I grew up in Kingwood, TX just NE of Houston. I'm at school in Daytona Beach, FL right now though... Dropping the tank is gonna be a major PITA! Friends gonna help me change the filter and check the coilpacks tomorrow. If no luck there, we'll try to check fuel pressures/pump and then may have it fixed by someone else...just don't have a workspace to tackle that task...

408WS6

iTrader: (1)

I'd be willing to bet there are still some ground issues. I'd start by making sure that the plugs on the injectors are plugged in all the way (its easy not to) and check all of the grounds on the PCM harness. Check also that there are no wires that have been burned by the exhaust.

When you took it to the dealer, they may not have got some connection snapped on all the way when they made their repair, and it may have worked itself off over time.

To me it sounds like an electrical issue and probably easily fixed. Theres my .02.

Will Clark

Ok, well if you smell gas that probably means that the fuel pump is pumping...check the O2 sensors for activity AFTER you change the fuel filter. Thats the cheapest way to troubleshoot this, it needs to be done anyway, and its likely related to the problem.

C5RUZR

iTrader: (4)

Changed the fuel filter, seemed to help, but it still won't idle smoothly 100% of the time, it's almost like random hickups in between smooth patches, and eventually it will die after ~1-2min. I checked fuel pressure at the rail, it's constant during the problems, so I think that rules out a fuel pump issue.

Feel like it must be an electrical/ground issue, but where? Anyone know what PCM grounds to check? I've cleaned the ones by the headlight motors on the front fuel rails, and the one by the battery terminal. I'm about to tow it in somewhere, because electrica troubleshooting is not a good time.

KISS: Fuel + Air + Spark + Compression + Computer: Fuel at rail YES, so if fuel is a problem its with the injector Air: Duh, the motor is runnning, and it will rev up, so don't think that's the problem Spark: Think this is cutting out, but with new plugs and fairly new wires - think it is the computer cutting not the plugs themselves, Compression: I hope so, can't seen how this would cause it and no event led up to it Computer: Hardest to diagnose and therefore most likely...

Pat7272

Is there any way to check that the coil packs and injectors are good by checking voltage? Other than that I would think to start looking for PCM ground issues, since that has been a problem before.

SiL3NtXWS6

iTrader: (17)

There are grounds on the back of the heads and on the side of the block near the starter.

Put the stock wires back on. Find 2 donor coil packs?

C5RUZR

iTrader: (4)

Stock plug wires back home, small chance of finding coil packs. Anyways, Eric and I messed around by the PCM, wiggled some wires, and ensured that the plug wires were all making good contact. Problems seem to have gone away. Unfortunately, since I have no conclusive scapegoat, I'm not convinced it's gone for good. Time to get AAA and hope...Back on the road...for now