masterprice33

I have a 1985 corvette that has suddenly started to randomly stall out, sometimes while at idle, at other times while coasting. Took it to my personal mechanic and we have tried replacing the fuel pump, MAF sensor, and IAC valve, and still having the same problem. I've researched a bit and discovered that it MIGHT be the TPS, knock sensor, ECM, fuel injector problem, was just wondering if anyone out there could provide some professional or personal advice. I haven't been able to drive my car for about 2 months in fear it will stall again. Usually it will start back up, but takes longer to start. Recently after stalling I won't even be able to start it. It sounds like a fuel problem but I figured the replacement of the fuel pump would do it. PLEASE HELP! ANYONE! ANY advice at this point would be appreciated, especially anyone out there who has witnessed this problem first hand, either as an owner or a corvette mechanic. Thank you.

Morley

Did your "mechanic" check for codes?
Also, there was a service bulliten released many years ago for the PROM chip in all 1985 TPI's...know if the chip was ever changed in your car?

MR NICE

How about the fuel filter? Checking the TPS is easy,do some reseach on this board and you can figure out most any problem with your car,you will get better info here than at 99% of the garages(rip-offs)

RRT vette

HUMMM, leaky fuel injector(s). Check pressure on shut down.

kopbet89c4

There might be water in your fuel. I had the same problem about 2-3 weeks ago. Put some Icy Heat in your gas tank and afterwards, change your inline fuel filter. Worked for me 100%. Good luck.

masterprice33

No codes came up and I had a new PROM put in when I first bought the car.

masterprice33

fuel filter was replace about 8 months ago and I haven't driven it much since then, I'll check on the TPS stuff thank you.

masterprice33

How could water get into my tank like that? My car was actually sitting in the rain for a good week before I ran it again. The thing is, it might be a coincidence, but when this problem started it happened after I took it into the Chevy shop to get a diagnostics test. Could a diag test do anything detrimental to the ECM, or anything else in the car for that matter? I'll try the Icy Heat thing and go from there thank you

RRT vette

I've never heard of a diagnostic test doing anything. I would still check the fuel pressure if you have a guage. Sould be between 36-42psi running, if it leaks down fast after shut down it could be a leak in injector, FPR, or check valve. You can ohm the injectors one by one to test resistance and they should not be much less than 16ohm each. Also do check the TPS. Usually if it is way off it will give a code. Mine was about .42v without a code but the car idled rough. Should be .54v closed throttle and 4.0v WOT. There are posts on here on how to adjust, if you don't know how.

masterprice33

Just to make a correction to your Icy Heat product, it's not actually Icy Heat (I was searching for that product for about an hour), it's actually "Iso-Heet" but that will be my next move, thanks for the tip. It makes sense.

goldeneye_vet

How about the diagnostic charts from the FSM? This would be the BEST place to start. The recommendation of the IAC and TPS is good but you need the charts to diagnose further. In the tech tips section of the forum there is a good write up on how to set the TPS and IAC. That procedure should get you closer to keeping it running if not fix the problem entirely. The FSM can be found at www.helminc.com or one from ebay if you can find them. Sometimes on this board they are for sale as well. Good luck!

masterprice33

thanks everyone for input I'll let you know if any of the advice has solved my problem

CentralCoaster

Where are you located?

masterprice33

I'm located in Eureka, CA, about 100 miles south of Oregon. I purchased this car from a guy in Las Vegas about a year and a half ago, why do you ask?

Midnight 85

Here's something you can try for free. My 85 ran perfect until the weather got over 60 degrees, above 60 degrees it would die as I would slow for a stop or die after I had stopped. It would always re-start after just a few moments of cranking. After checking everything I could think of and doing a complete tune-up a friend suggested the ECM was getting hot and shutting down. I went ahead and got a new ECM and the problem stopped. No sense in you buying a new ECM until you know you need it, Put an ice pack against the ECM, wrap it in a cloth so it won't get anything wet or, put one of those small fans truckers use to clear their windshields. Place the fan so it blows on the ECM and keeps it cool. Then if the problem goes away it's time to get yourself a new ECM.

RRT vette

another good suggestion! easy to do.

masterprice33

the only thing is....I bought the car from Las Vegas, temperatures around 100 degrees, and transferred it to my town that never gets above 80, usually is around 50 degrees on the coast, so that wouldn't do anything for me. But that is a pretty ingenious idea thanks anyway!

ghlkal

Since the PROM was replaced, I'd double-check the connectors to the ECM. I had a somewhat similar problem. After testing almost everything else, I finally discovered that one of the pins inside the connector to the ECM was pushed out and not making good contact.

Gary

RichS

I just finished a 86 that had the engine/trans replaced but not finished by the other idiot shop. After getting it running when driving it would shut off. Once on the side of the road it would restart, drive a little then stall. I found the connector after the fuseable link bad. The vibration of running the car would loose the connection that fed the fuel pump relay. Then shutting off the pump.
The connectors are under the brake booster running off the small red wire off the battery. (If this is the same on a 85 as 86).

Try hooking up a fuel pressure guage while driving and see if the pressure drops off just before is dies.

87 rag

I would do this first to rule out fuel problems (first after water remover in the tank). Tape the guage to your windshield so you can see it when you drive.