1987 turbo coupe high idle

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1987 turbo coupe high idle

August 04, 2008, 12:59:30 PM

My 1987 turbo coupe has a high idle when in park and nuetral. Its only after its been driven a little bit and is warm.

Am i supposed to let the engine idle high after i've been driving the car for turbo cooling purposes?

I tried letting the car idle for a couple of minutes but it didn't idle down. Any ideas?

John

1987 turbo coupe high idle

Reply #1 – August 04, 2008, 01:35:44 PM

Is it throwing any codes?

1987 turbo coupe high idle

Reply #2 – August 04, 2008, 02:42:10 PM

No. the engine light does come on if i accelerate hard and let off the gas. It stays on for a couple of seconds and turns off.

1987 turbo coupe high idle

Reply #3 – August 04, 2008, 02:45:48 PM

What is your definition of "high idle"? They will idle higher in Park and Neutral normally.

The IAC valve may be sticking (the canister-looking thing bolted to the intake near the throttle body).

Odd that you're not seeing any codes, but getting a CEL.

1987 turbo coupe high idle

Reply #4 – August 04, 2008, 03:48:04 PM

A high idle is around 2000. Maybe a bit under. It only does that if the car has been driven with the turbo spooling. If i dont put my foot into it it wont do it. If the turbo spools up once itll idle high. Is this supposed to happen? How long does it usually idle like this?

Is it safe to shut the car off when its doing this? Whats its purpose?

1987 turbo coupe high idle

Reply #5 – August 04, 2008, 03:53:30 PM

There is no purpose, something is not working properly.

You say you did run codes and got the "11" "All clear" code?

Remove the IAC and clean/blast the valve out with carb cleaner. Sometimes they hang up.

Check your TPS voltage at well.

1987 turbo coupe high idle

Reply #6 – August 04, 2008, 08:06:27 PM

I haven't checked for codes, but seeing the check engine light only comes on and off occasionally i figured it wouldn't be throwing codes.

I cleaned out the IAC to no avail. It may have helped a little bit. I put 60 miles on the car and the check engine light only came on twice. For about 10 seconds each time. I was doing 50-55 at about 2000 rpm. It comes on if i let off the gas, and the car starts to decelerate.

Where is the TPS on these cars?

and it has nothing to do with the throttle linkage. Its bottomed out, and in park the tach still winds up to around 2000.

I figured this might be to let the engine spin after the turbo spools. I read somewhere on this site never to just shut the car right off after driving it. But maybe its more serious.

1987 turbo coupe high idle

Reply #7 – August 04, 2008, 08:20:35 PM

Ya your suppose to let the turbo stop spoling by letting the car idle for a minute or two before u cut the car off this goes for all Turbo Cars.

1987 turbo coupe high idle

Reply #8 – August 04, 2008, 08:55:44 PM

Run codes. Otherwise you're just guessing. Period. Until you run codes and at least get that info, no one else is going to be able to help you either.

There is NO coding in the stock ECU that raises the idle for turbo "cool down".

And the turbo doesn't "spool" at idle....

1987 turbo coupe high idle

Reply #9 – August 04, 2008, 11:36:57 PM

If the light has come on and went of there still might be a codes stored. The tps is on the throttle body on the back side. Check and make sure that it is set at about .97volts. Then the only other thing that comes to mind would be that maybe the temp sensor is dead or the wires to it are shorting and causing it to think that is it cold. Never can tell best to get out there and look into it like we've told you.

1987 turbo coupe high idle

Reply #10 – August 05, 2008, 07:09:53 AM

Codes will be stored with or w/o a CEL...

1987 turbo coupe high idle

Reply #11 – August 05, 2008, 10:11:57 AM

Alright. Now autozone only has a code reader for obd2. Do i have to take it to a garage? do they make a cheap code reader for the older cars?

1987 turbo coupe high idle

Reply #12 – August 05, 2008, 10:20:31 AM

You don't need a reader....

Go HERE and read the procedures for getting codes on the Tech Articles page....

1987 turbo coupe high idle

Reply #13 – August 05, 2008, 08:38:12 PM

Codes, codes, codes, codes....

JeSUS!!!

With all the turbo cars on here I'm sure somone has run into this problem before. Why can't some one just say, "Hey, that happened to me one, turned out the IAC was sticking."

No. Everyone has to have CODES so a computer can tell you something that someone already knew.

1987 turbo coupe high idle

Reply #14 – August 05, 2008, 09:31:47 PM

I gave him the IAC option...he tried it...no dice.

Working on an EEC4 car...you are shooting in the dark without the codes, 2.3T, 5.0 or not. They are called diagnostic codes for a reason.

We could continue to guess...he could continue to throw parts and time at it...and maybe, eventually the problem might be found.

Coming in looking for a solution to an engine issue, CODES should be almost as mandatory as what car you are working on, period.