1990dtgL98

I have a 1990 Corvette. On the highway and general cruising, every once and a while it will loose all power and die out, and i have to quick compression start or turn the key over and start it while on the road. Once I compression started it, and it backfired, which was loud enough to completely scare my gf. I'm use to backfiring on deacceleration, but this sounded like a 12 ga. shotgun.

I dunno what it could be? Bad gas? Water in the tank?

It starts fine, idles fine, and runs fine except for the one or two times in a trip where it will completely die on me.

Any hints? I have to do a 2 hour roadtrip tomorrow and don't want it to happen on some interstate.

Thanks!

Dave

black96lt4c4

when i was young i would turn off the ignition on my grandpas fence truck and pump the gas.with the key off,unburned fuel would enter the combustion chamber.turn the key back on,spark plug fired,unburned fuel ignited,big backfire out the exhaust.scare the heck out people.when does it die?hot,cold,backfire under hood,or out tailpipes. sound like a loss of power to ignition system,causing unburned fuel to ignite.good luck.junior

1990dtgL98

To add more:

Does it hot, cold, on startup, after its been running....basically it has done it at every point, with no pattern in that regard.

The backfire was so friggin' loud, I couldn't tell you wheere it came from...but it sounded like the exhaust.

vinnies87

1990: Allentown huh, lived there from 1953 to 1969, then off to Nam... that brough up some memories... thanks for the flash-back to child hood.

Mike_88Z51

Unburned fuel enters my combustion chambers all the time.
Perhaps you meant to say that unburned fuel exits the combustion chamber and enters the exhaust. Then, when you restart it will backfire with a vengence.

1990dtgL98, it sounds like you are experiencing either an electrical loss of power, or an injector is flaking out on you causing an excessively rich situation that kills the engine. When you restart, the unburned fuel in the exhaust is igniting, causing the backfire.

Does everything (radio, a/c) seem to die at the same time the engine dies? If so, I would guess that it has to do with a) Battery connections, b) Ignition module, c) Alternator, d) other electrical wiring issues.

My brother had a similar issue in that his 89 L-98 would act funny on the highway at times and just die for no reason at idle. Like your situation, it didn't seem to matter if it was hot, cold, idling, highway, etc. We found that the battery cable bolt was broken in the cable retaining ring at the post. The cable would jiggle on the bolt, causing high voltage fluctuations at the post and affecting engine operation or killing the engine alltogether. You had to actually PULL on the cable to see the movement at the post bolt.

JamesRS

The backfire that you mention is from excess unburned fuel. That would indicate to me that you are having an electrical problem with the ignition system. Did you check to see if there are any codes? A stall like this should throw some codes and give us a place to start looking.

1990dtgL98

No codes.....it looses power, but everything else, headlights, radio, gauges, etc....remain on.

I added some dry gas and it seems to be working. I think it was either something with water in the fuel, or after the huge downpour, the distributor might have gotten wet and finally dried out....though I would have thought it would have been quicker than the 3 days it took.

So far, today, no issues. Knock on wood. I'll keep you guys posted if it does happen on my way to work.

JamesRS

Good to hear that it's running ok.

Mike_88Z51

I'm betting that perhaps the "huge downpour" caused water to get in the fuel tank. Adding some dry gas helped the fuel pump deal with it. If that was the problem, you should check the hose that goes from the heavy rubber fuel overflow gasket around the fuel pipe inlet down to the ground. If that hose is blocked or partially blocked, then water will fill the overflow gasket under the fuel door and make its way into the tank. I'd make sure the hose flows easily to the ground.

I'd also seriously consider pulling out the fuel sending unit and checking its condition. A lot of water in the tank could cause the fuel pump to fail on you prematurely. If you remove the sending assembly and shine a flashlight into the tank you will see what looks like snot in the bottom of the tank. That's water. Use some cheap plastic tubing from Home Depot or Lowes to siphon all the water out.

The fuel sending assembly is held in by 10 bolts with rubber o-rings and a rubber gasket. I'd inspect the o-rings on all 10 bolts and the rubber gasket for replacement. If any are too old or misshapen, water can get in the tank when it rains hard. They are available at the $tealership and ar not that expensive. If you've never done it before, the whole project should take less than 3 hours with basic hand tools. Once you've done it before, the next time will take about 30 minutes. Very easy to do and may save you having your fuel pump die in the middle of a trip.