So I decide to pressure wash the engine on my 92 Corvette LT1 today and unfortunately it was a big mistake. I had the car running while I was doing it and was careful not to spray the computer or any other electrical things. The car was running fine until I sprayed by the rear of the manifold where the fuel lines are going in to the fuel rails. Once I did that the car started to shake and the idle was jumping up and down and the exhaust started popping. I went to put the car in gear and it died out. I thought I may have gotten something wet that I shouldn’t have. So I let the car sit for a couple hours and tried to start it only to have the car act the same way and die without putting it in gear. I then noticed something was smoking. The smoke looked like it was coming from under the spot where I sprayed and the car starting acting up. The car is acting like it has some kind of vacuum line knocked off. I looked and didn’t see any vacuum lines loose or knocked off. I am so mad at myself for doing this and I just don’t know what I may have messed up. If anyone has any insight please help me figure this mess out.

 

Keep the hood up and put a fan in the area to help the water evaporate. It can sometimes take a while once water is in a place that you don't want it to be.

 

Possible that the pressure washer drove some water into the fuel line connections at the rear end of the rails. Anyway, start with the basics- spray a SMALL sniff of ether into the intake while cranking to see if the car tries to start. Check for spark while cranking with an inductance-type timing light or by pulling a plug wire and laying it against a grounded spot, with an old plug in it if you have one. These tests will point to lack of fuel or spark as the problem, go from there.

 

Any real amount of water sprayed onto the Opti-Spark will kill it. Doesn't have to be under pressure, even a garden hose can drown it.

It may be possible to remove the cap and dry everything out, but I'll bet that a new Opti-Spark is in your (near) future. This will be a good opportunity to replace the water pump. If yours is the original pump, chances are it will eventually leak. And it sits directly over the Opti.....

 

Even if you didn't directly spray the opti there is a good chance it got wet. I would let it dry out for a while and it may run better. My friend once hosed the motor on his 94 and it died on him, he let it dry out for a while and it ran good again. Once moisture gets in the opti though it will start to corrode over time and its life expectancy won't be very long.

 

I just went in the garage and tried starting it with positive results. Now the only problem is that it is running ruff and the exhaust keeps popping like it is missing. The RPM's keep jumping from 800-1100. I did noticed before this whole water incident happened that the car would start fine, but once I would hit the gas pedal (while driving) the exhaust would backfire and and then it would stop then go drive fine. I was thinking that maybe my opti was dying a slow death before I may have just killed it totally. You got to find some humor in things even when they are not good things.

 

Bump for help still.

 

Now that you got it started, see if you can retrieve any codes from the ECM. The engine would not be running when you do this, and you don't need any equipment, just a paper clip. You can find instructions on the exact procedure to follow in "search" or in the sticky threads at the top of this forum.