cymro

Ive just tried to reset the idle on my 1987 after fitting a new IAC valve. I followed the procedure as written in the GM manual, and when i connected things back up, the car was idling at 1400 rpm! So i just turned the screw down again, which defies the point of resetting it to the book really. Should i have left it at 1400 rpm and taken it for a drive to let it "settle"?

vinnies87

Don't know if you followed this process, but it works - make sure as your adjusting the idle, you bump the throttle to seat it, sometimes it gets stuck and you don't reall know what the actual adjustment is really at...

1. Warm the engine.
2. Ignition "Off, engine "Off". Jump terminals "A" and "B" of the ALDL together.
3. Turn ignition to "On".
4. Wait 30 seconds, then unplug the IAC connector.
5. Turn the ignition "Off".
6. Remove the ALDL jumper.
7. Start the engine and adjust the minimum air to the specified (desired) rpm.
8. Shut off engine, connect IAC.
9. Ignition "On", adjust TPS voltage.
10. Acclimate the IAC. Some cars have an ignition on/off procedure, but it will happen on all C4s, if you take it, warmed up, for a drive and exceed 40 mph.

Apparently, some year FSMs say to disconnect the EST wire. Most *I* am aware of don't. If the manual says to disconnect the EST, then disconnect it.

AGENT 86

You should have left it, the IAC will reset itself the next time you start the car. If you turned the min idle screw to lower it, you also just messed up the TPS setting.

CFI-EFI

Pure genius! Well written, concise and precisely in proper order. I couldn't have said it better myself. Maybe just as WELL post #14, but not better.

RACE ON!!!

cymro

I didnt adjust the idle because of the IAC valve. It was idling roughly anyway. I wanted to make sure the idle was correct because at some point, somebody has adjusted the screw.

CFI-EFI

You CAN'T adjust the idle. The idle is burned into your prom. See my answer to this same, exact, question, HERE, post #27.

RACE ON!!!

cymro

I definately CAN adjust the idle.....if i turn the screw on the throttle linkage, the idle goes up or down.
Is this screw the same thing as "min air adjust"?

Pete K

mseven

You do mean Throttle Body Right?
I believe it is possible to turn it in so far, as to out of range of the ECM to compensate or be in control which would bring up the idle speed.(Likewise to low).
HOWEVER, THIS IS NOT what you are trying to accomplish when setting min. air adjustment.
BTW, the idle speed (base etc.)is PROGRAMMED in the chip(prom) and is absolutely correct as CFI has already said.

cymro

Leaving crappy icons really does not help me.

CFI-EFI

Then what is this thread, which is the duplicate of one you hijacked, here for in the first place? Since you CAN, adjust your idle, do it and be done with it.

RACE ON!!!

mseven

My suggestion for you is to re-read, try it again, follow directions, take your time, and see if you can get it right.

Pete K

Neither does ignoring good advise. You asked a question, presumably because you do not know the answer. The replies that I read were absolutely perfect. Then you chose to debate it. Hense the head banging. Some members, myself included, answer the same questions over and over, year after year because people are reluctant to use the search feature. I would suggest reding this entire thread again. All info seems to be here.

cymro

Listen guys...the hyjacked thread was mine to start with. Im not debating or disputing any advice that i am GRATEFULLY recieving. All i am saying is that after following the correct procedure my car ends up idling at 1400 rpm. Now that ist right is it?

mseven

No 1400 rpm would not be correct. Two things: 1st, by any strange chance did you remove any vacuum lines, or disconnect something by accident ? 2nd repeat the entire procedure, and take your time making sure it is done by the steps.

CFI-EFI

So handle it!

RACE ON!!!

cymro

The vacuum lines are fine....i cant repeat the procedure just now because its the middle of the night here in the uk. I think we are all having differences in terminology..(or i am rather). My GM manual talks of adjusting the idle speed by turning the screw on the linkage on the side of the throttle body....but you guys are calling this the minimum air adjustment...am i correct?

mseven

That's where filling out your profile helps.
It is referred to as: "adjusting min. air" because that is what you are doing, there is no fuel in the throttle body. I must not understand an 87 Throttle Body, "a screw on the linkage side of the throttle body" . Does this mean that the screw you are adjusting is not in a recessed area above the throttle cam?

CFI-EFI

The thread you didn't hijack wouldn't be THIS one, post #25, started by ozvette87 would it? Do you know what hijacking a thread is?



I'd like to see a scan of the FSM that advises the setting of idle speed. But nevertheless, you say you can adjust your idle speed, so do it. You don't need to continue to aggravate us dummies.

RACE ON!!!

cymro

Its on the drivers side of the throttle body, where the throttle cable is connected. The screw adjusts the position of the discs in the throttle body, or "butterflies" as we tend to call them, in relation to the linkage. Its all well and good these other guys saying this is what your car WILL do...etc. but i did say right at the start what my car IS doing. I cant help it if it doesnt comply with their presumtious ideals.