the car is idling around 1200. i dont have any vaccuum leaks or a cracked EGR (checked with TB cleaner). and my dad said he would adjust the idle, but he doesnt know where the idle spead adjuster is.

anyone know where to find this? pictures would help a great deal too.

Thanks,
Steve

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87 GT Auto: New Ignition System, New Stereo System, New Radiator. Needs rear tie-rods to pass inspection.
AIM: derangedsheep | email: elcodjsteveo@comcast.net

should be on top of the throttle body.. not sure if that screw was put there on my modded TB or if it was stock.

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88 5spd Modified 3800 Series II SC Formula Yes it whines... do you?
Modifications/2004 - Intercooler 3.0 pulley, 1 inch drop, interior

There is no idle speed adjuster. You either have a vacuum leak you haven't found, the timing is off, or the IAC is not working properly.

where is the IAC? i just set the timing, so im sure thats not off (the ALDL was jumped when i set it)

It's circled below:

I'd remove and clean the throttle body. That way you can remove the IAC (Idle Air Control) and clean the seat, too. If the engine is high mileage you may need a new one.

Careful when putting the TB back on, the vacuum tube on the lower rear is a bit difficult to seat properly, and will leak if not seated. It helps to apply a little grease to the seal where the tube goes.

Good luck!

[This message has been edited by Denny (edited 11-13-2003).]

There is an idle air adjustment screw also. It is usually covered by a plug and is supposed to be set from the factory. It adjusts the amount the butterfly stays open, if yours got screwed in somehow, it could raise your idle speed. You shouldn't depend on this to set your idle properly. You need to make sure that your timing is set correctly and that your sensors are working properly, as these are what truly control the idle. The ECM receives information from these and adjusts the IAC to set the idle. If the IAC seat is dirty, it can hold it open a bit and raise the idle also.

I always say that there is no adjuster, since that's the 1st thing lots of shadetree mechanics will go for, before they make sure everything else is working properly.

Point is, you shouldn't have to screw around with that setting. If the previous owner did, I'd find another TB.

[This message has been edited by Denny (edited 11-13-2003).]

quote Originally posted by avengador1: The ECM receives information from these and adjusts the IAC to set the idle.

what sensors should be replaced? theres a good chance that most of mine are dead or working improperly, as the previous owner did not take good care of the car.

Look again for vacuum leaks - there's at least one that you haven't found yet.

Don't forget the power brake booster and the line running up to it. You might want to try disconnecting and plugging vacuum lines one at a time to find your leaker - I guarantee you there's a leak.

Some sensors used are TPS, CTS, MAP, and the intake temperature sensor. You could also have a bad O2 sensor which could make the engine run rich.

ok, i know where the MAP and the O2 are. And i replaced the intake temp sensor. there is the TPS and the CTS? and what does CTS stand for?

The ECM controls the idle by adjusting the air flow through the IAC valve. This air bypasses the throttle plate by way of a tube that goes from the bottom of the throttle body to the manifold near the distributor.

The IAC screws in to close off air flow and drop the idle, and screw out to increase the idle. It does this in discrete steps since the IAC is a stepper motor. If the ECM runs the IAC all the way down to zero steps and the idle is still high, then you either have a vacuum leak or someone has jacked with the factory idle stop screw. This screw is on the top of the throttle body, on the throttle cable side. In the picture posted above you can see the boss next to the cable, there's a circular plug to prevent tampering with the screw.

To properly set this requires using a scan tool to see the steps being commanded by the ECM and adjusting the stop until you see 16-20 steps with the A/C and radiator fan off. If your TB shows signs of having been tampered with, you can go ahead and rule out a vacuum leak by screwing the stop out, counterclockwise, to fully close the throttle plate. If the engine continues running, you need to find out where the air is coming from.

JazzMan

quote Originally posted by Denny: I always say that there is no adjuster, since that's the 1st thing lots of shadetree mechanics will go for, before they make sure everything else is working properly. Point is, you shouldn't have to screw around with that setting. If the previous owner did, I'd find another TB.

AMEN

TPS= Throttle Position Sensor, CTS= Coolant Temperature Sensor. There also is an intake air temperature sensor on the air filter can.

[This message has been edited by avengador1 (edited 11-14-2003).]

Just look at the TB adjusting screw and it should be "plugged" so no screw head is visable. If you can see a screw, then someone has been messing with it. Some guys will use it to mask vacumm leaks. You should be getting an idle speed error code at 1200 rpm...Paul

[This message has been edited by Paul Prince (edited 11-14-2003).]

yes, dont mess with the "idle" screw. you will not make the car idle any better. 3 main things for good idle:
1> no vacuum leaks
2> working & CLEAN Idle Air Controller (IAC) 3> good power - good ground, good alternator, 13+ volts at idle
I myself have low power at idle, and it will start to hunt around, espeically on cold rainy nights sitting at a light. I clean the IAC by shooting throttle body cleaner down the IAC hole. you can remove it, and do a better job. but, if you've never cleaned any of the throttle body, maybe just removeing the whole damn thing, and giving it a good flushing out will do you some good. get a nice shiney butterfly again, no sticky's or crusty's that may be holding it slightly open, and a nice clean IAC.