0 to redline in the turn of a key.

[ironhead]

OK my son's 90 EX w/ auto ran great until today. We replaced the VSS because the speedo didn't work and the S light was blinking. The new VSS fixed them both. Drove it fro about 12 miles and all of a sudden the motor revs up by itself and doesn't stop. He had to pull the car over and kill it because the brand new brakes on the front couldn't hold the car. Now when I turn the key it goes from 0 to wide open. Tried to pull the CEL codes but nothing happens. The engine light just stays on solid. I don't have a clue where to start looking for this problem. Anybody have any ideas?

Oh yeah, unplugged the new VSS and it still does the wide open thing.

[foamypirate]

I'd check to make sure the throttle butterfly didn't get stuck at WOT.

[wed3k]

so with the key on and engine off, the cel stays solid?

[Losiracer2]

check the throttle cable for any kinks that could be holding it wide open

[9DUBWISE]

My 87 Escort gt did this. Floored it then went to shift, straight to rev limiter. Turned car off. Restarted and was fine. Floored it again out of curiosity and same thing again. Re started again. 0-redline, turned off for 30 sec. Restarted then drove away. A couple of days later a tree fell on it and crushed the Lt 1/4 panel. Still drove it for about 2 yrs after that and never did it again. Aggrivating!!

[ironhead]

Yes the cel stays stays solid. didn't even pick up on the unplugged VSS. throttle cable not the issue here.

[bcjammerx]

the brakes wouldn't hold because the vacuum booster lost vacuum, you'll damn near pull the steering wheel off to get leverage when that happens, and still can't stop.

If it goes WOT and the throttle plate isn't open could have a major intake leak.

if the throttle plate is staying open you could have a binding throttle body mechanism or cable

might wanna check the cruise control module...it works by actuating the throttle...if it's messed up or something connected to it may make it open.

my .02

[ironhead]

the brakes wouldn't hold because the vacuum booster lost vacuum, you'll damn near pull the steering wheel off to get leverage when that happens, and still can't stop.

If it goes WOT and the throttle plate isn't open could have a major intake leak.

if the throttle plate is staying open you could have a binding throttle body mechanism or cable

might wanna check the cruise control module...it works by actuating the throttle...if it's messed up or something connected to it may make it open.

my .02

Can you tell me where the cruise module is and how to check it?

[ironhead]

Yeah as I said I tried to pull the cel codes but the light stays solid. If it is a bad ECU, Would this cause the engine to run away?

[TypeG]

did you take the rubber intake hose off to see if the throttle body is stuck open? later.

[ironhead]

I've seen damn near everything now. I took off the hose going to the throttle body like TypeG said and there it was. A small piece of plastic that must have been in the hose when we took it off to access the VSS to replace it come loose and had the butterfly valve open about a 1/4". Had to have the ECU screaming MORE FUEL!!!! Took it out and made sure that nothing else was in there and it runs like a champ again.

Dammit Boy was real lucky though. My boy was driving it when it went WOT. He's had his license for about 5 months now. If I hadn't of been behind him with a 2 way radio checking out they're range and talked him through it he could be dead right now.

[Shag Wagon]

Yea the ECU will give a solid light when there are no codes. This does NOT mean you have a bad ECU. I thought everybody would know this.

[HondaFan81]

Glad your boy is OK and you were in communication.

Where did the piece of plastic come from? Was this something you should have observed while doing the job or introduced? Always pays to inspect things and be careful.

[foamypirate]

I'd check to make sure the throttle butterfly didn't get stuck at WOT.

[ironhead]

Glad your boy is OK and you were in communication.

Where did the piece of plastic come from? Was this something you should have observed while doing the job or introduced? Always pays to inspect things and be careful.

I guess that a small piece came off of the air duct when I was putting it back on the throttle body. It's all I can figure anyway. Will pay much more attention from now on. To think that something so seemingly minor could cause a serious situation.

Thanks to all you guys for the input.