Last year before Super Chevy @ Indy, I was cleaning up my car and decided to "wash" under the hood. It is clean, but was dusty from driving. I went to the local car was and used the baton to clean under the hood.....lowest setting with no pressure. It ran fine for the next 2 hours, but for some reason started acting up later in the night. The engine revs really high (1200-1400 rpm) at idle and really falls on it's face on the top end. This car really hauled bauls b4 I did this.
I heard that there are several things that are very suceptable to water under the hood. I heard that the throttle position sensor is one thing that should never get wet. I am sure it did that day. It is getting warm and I want to get her out, but not running like this. Any ideas will help......
By the way, it's a 1991 Z28 5.7L TPI. It is showing the service engine light right now, and I hope to get it in to Chevy to see what code it's throwing, but does anyone know what this may be?????
Thanks,
Dylan - 911rsq

 

Cold water can fracture the spark plugs on a hot engine.

 

you can check the codes with a paperclip from under the dash. maby someone can elaborate more.

 

water in the distributor?

i dont think that would put the SES light on..but who knows

just an idea

 

I will check the plugs tomorrow, but it sounds and feels like it is hitting on all 8 cylinders. Moisture might have gotten under the distributor, but this was last fall and it still runs rough.... . I am in the process of trying to sell the car and I want everything to be perfect....

 

I killed my IAC by getting it wet, idle went up, wouldn't start very well, no code though...

 

KISS.

Did you knock any vacuum lines loose, and then they fell off two hours later? Might want to check that.

If that shows up good, then you can test your IAC.

It sounds like a vacuum leak to me, but I'm no expert... just gotta find out where it might be coming from.

 

Cool, I will do that in the moring....vacuum and IAC...got it!!

 

Alrighty....checked it all out. Distributor is dry. Had a friend of mine hook it up to his scan tool at his garage and the TPS voltage is low. Will have a new one here by tomorrow and hopefully problem solved. Thanks all......

 

Why not just try adjusting the TPS?

 

and cleaning it

 

exactly - what he said... probably just loose. you'll need a volt meter to reset it, but you can tell if it's loose obviously just by checking it.

 

Yeah it's NEVER smart to clean an engine like that.. for a few reasons.

1. It was hot. Hot block + Cold water = Cracked block. Seen it happen.

2. Should have covered up sensitive stuff, i.e. TPS.

3. Should have used simple green, rags, and a spray bottle of water, not a hose.

 

I agree that it is a bad way to clean under the hood, but I was doing a last minute trans rebuild and ran out of time and didnt get to really detail it out..... Just hosing off the loose stuff to go to the show. I am def going to try to adjust it first, but from the readings we got on the computer, it's prolly shot...
I am going to check it out either way. I have the new one here just in case..