Is a 800/900 rpm idle a problem

[ROLLingKING]

It may not be a problem but I would love it if my car would just idle the right way. Im thinking it could be the TPS or the ICV ive cleaned everything and replaced pretty much every hose under the hood but it still idles high. And sometimes if im in neutral and rev it the rpm's wil sometimes drop and then bounce back up.

Im probably going to keep trouble shooting but any help suggestions would be muuuch appreciated.

[timofeylbelarus]

dude i got the same problem, pisses me off, im thinking maybe a bad O2 sensor, but idk, trying to figure this out too

[iXe<30]

same guys.... from what ive read it is the icv needing replaced ive seen a few on here for lik 25 bucks but that might be because it has the same problem as ours

[mbonanni]

I have the same ):

I tried two diff ICV's to no avail.

[Jaxx_]

idle adjustment screw?

[mbonanni]

ahh the cheap way out! I have an 86 and the elctornics are so outdated to me. I will do it.

[Gregs///M]

I'd get a smoke test done because it is most likely a vacuum leak. But also be sure to test TPS (very important.) Spray out ICV with carb cleaner. Fill it up and shake it really well while plugging each end. Repeat many times to clean it well. light mist of wd40. Counter weight valve should easily sway open and closed.

Also measure resistance across coils to see if they are within spec. See ETM or repair manual.

Its very rare to find a M20 that idles perfectly like new.

[PNWDan]

idle adjustment screw?

Unless it's been messed with, you should never have to adjust the stop screw. The computer controls the idle with the ICV. The ICV is actuated based on the position of the TPS. If both check out, you should be looking for vacuum leaks. On a rare occasion the DME can go bad and cause this too. Mine did. I would have it tested for vacuum leaks first.

[jlevie]

Have a smoke test run. While there could be other problems, until intake leaks are eliminated or ruled out it is pointless to look for other faults. The O2 sensor is a scheduled maintenance item with a replacement interval of 100k, if that applies replace the sensor.

[Jaxx_]

Unless it's been messed with, you should never have to adjust the stop screw. The computer controls the idle with the ICV. The ICV is actuated based on the position of the TPS. If both check out, you should be looking for vacuum leaks. On a rare occasion the DME can go bad and cause this too. Mine did. I would have it tested for vacuum leaks first.

i thought all M20s were WOT switch TPSs... I don't know how it would control the ICV based on that.

[jlevie]

The TPS contains an idle switch and a WOT switch.

[ROLLingKING]

WOW
I havnt checked back here but im going to give a new ICV and TPS a try. Then crank sensor. i dont think that is the problem but it wouldnt hurt to have fresh sensors. Ive cleaned the ICV a few times but ill try a new one. I dont really want to smoke test it as ive replaced every old looking hose under the hood, but it couldnt hurt i guess.

And adjusting the idle screw was my LAAST fix. I tried getting the little plastic cap out and it just crumbled and broke in the hole. I went to the JY and found one with the idle adjustment screw accessible so after new sensors im gonna put in the spare and give it a try.

nice knowing im not alone.haha
thanks for all the suggestions. Ill keep this updated as i try solutions.

[jlevie]

WOW
I havnt checked back here but im going to give a new ICV and TPS a try. Then crank sensor. i dont think that is the problem but it wouldnt hurt to have fresh sensors. Ive cleaned the ICV a few times but ill try a new one. I dont really want to smoke test it as ive replaced every old looking hose under the hood, but it couldnt hurt i guess.

I'm pretty meticulous when it comes to working on an engine, but even with everything new on a rebuilt engine I've had small intake leaks every once and a while. Usually because some gasket or seal got damaged during assembly or was bad out of the box. So I routinely smoke test.

[the_ps]

Also check the metal elbow for the ICV and the other one for the EGR. They can leak where they go into the throttle body. That was the cause of my bad idle. If you can turn the elbow, it leaks.

[ROLLingKING]

Also check the metal elbow for the ICV and the other one for the EGR. They can leak where they go into the throttle body. That was the cause of my bad idle. If you can turn the elbow, it leaks.

yea imma try those out..did you j-bweld the gaps or is there a way to replace them. I already know theyre a little lose but i figured if they were in they were good