Patrick_66

Took my car to the car wash - no, I didn't wash the engine - and it started right up. Drove it to the vacuums. Dried the car, cleaned it inside, and no start. It turns over fine, and acted like it wanted to start. Had the car hauled home from there, and let it sit a few days. Today, I hooked the fuel pressure gauge up to it, and got 44 pounds of pressure, but still no start. No "security" or "check engine" lights; just the normal lights that are present during start-up.

The car is an LT1 automatic with 161K miles on it, on an unmodified LT1 engine. Stock exhaust and all. Ideas?
Thanks!

Joe K

Check for spark.

Patrick_66

That's next on the list. Don't know why it would simply quit like that, though. It's 38* in my shop, it'll wait til tomorrow! LOL.

bac22

DIY car wash or automatic car wash...some of those automatic ones will spray under the car causing the opti to get wet.

don hall

Optis can quit any time

pacoW

Fuel pressure is good so next is spark. Optispark's can quit right out but more often I've seen them give up some warning signs first, usually a miss at idle and part throttle. ICM on the other hand, when it goes, it's done, no spark at all. I think you can lookup ICM and coil test or have them tested.

KyleF

Most part stores have a tester for them.

Patrick_66

Well, I had it running for about 39 miles today...then it died. Again.

I replaced the ICM, which was 30 kinds of dead. I also replaced all eight spark plugs; because in trying to start it previously, the plugs were soaked in fuel. The coil sparks all day long, and the Optispark is fine. The car started right up and idled fine. Took it out and drove it from stop-n-go traffic to 75 mph highway speeds. Got off the exit ramp and the car started dieseling really bad as I was coming to a stop. I had enough momentum to get the car to the shoulder. It started again, but only ran for about three seconds, all that time, dieseling heavily before it quit. NO warning lights or other indicators came on while all this was happening!

So, now I'm back to square one.

don hall

How do you know "the optispark is fine"?

pacoW

So process of elimination here, start simple. New ICM, you said the old one was dead. These things can get real hot and need that thermal grease underneath, did you do that? Did the coil test good or are we just assuming by looking at a plug attached that showed spark? In general once you're sure coil and ICM are good, wires & plugs are good, ignition issues usually wind up with the opti. The only other thing I might check out would be the cats, potentially being plugged.