Idle Learn Procedure

[ctaylor2]

Can anyone help me with the idle learn procedure for 1992 cav.
I cleaned and checked the IAC valve but car still stalls at idle.
The car was bought with this problem and I see it has a new battery so I would like to try the pocedure before replaceing to many parts.

Thanks alot

[SpitAndDirt]

you should remove the IAC and try and move the pintle as far back into the body of the IAC as possible. It is a stepper motor, as such, it has four terminals. Each terminal when engerized by the computer will cause the pintle to move in or out a very small distance. If you screwed the IAC back in without doing this, you may have damaged it. The idea is to install the IAC fully retracted and then then turn key to ON, engine OFF and use a paper clip to bridge terminals "A" and "B" on your Diagnostic link connector. Not only does the car go into diagnostic mode and the check engine light will flash codes, the IAC with automatically close all the way. The IAC is now set. When you start the car and no other problem exists, the computer should learn the idle. Other things to check, depending if you have a 2.5L or the 3.1L would be the Manifold Absolute Pressure Sensor(or Mass Air Flow Sensor if equipped) , and the Throttle Positions Sensor(TPS). If the problem ends up being TPS, it also needs to be set to the proper minimum voltage. This is done if the TPS has oblong holes for adjustment. Some TPS are just bolt on. With out knowing if you have any codes, or engine size I can only diagnose so much. Hope this helps -Chris

[ctaylor2]

Originally Posted by SpitAndDirt

you should remove the IAC and try and move the pintle as far back into the body of the IAC as possible. It is a stepper motor, as such, it has four terminals. Each terminal when engerized by the computer will cause the pintle to move in or out a very small distance. If you screwed the IAC back in without doing this, you may have damaged it. The idea is to install the IAC fully retracted and then then turn key to ON, engine OFF and use a paper clip to bridge terminals "A" and "B" on your Diagnostic link connector. Not only does the car go into diagnostic mode and the check engine light will flash codes, the IAC with automatically close all the way. The IAC is now set. When you start the car and no other problem exists, the computer should learn the idle. Other things to check, depending if you have a 2.5L or the 3.1L would be the Manifold Absolute Pressure Sensor(or Mass Air Flow Sensor if equipped) , and the Throttle Positions Sensor(TPS). If the problem ends up being TPS, it also needs to be set to the proper minimum voltage. This is done if the TPS has oblong holes for adjustment. Some TPS are just bolt on. With out knowing if you have any codes, or engine size I can only diagnose so much. Hope this helps -Chris

Thanks Chris

It sounds like U know alot about these cars I did have the pintle in all the way and it did race when I first started it and then calmed down.
I have no check engine light on and it is a 2.5.
I will try jumping the A & B terminals and see what that does hope it works.

Thanks Again for the HELP!!

[SpitAndDirt]

I almost forgot to say that after you bridge the terminals for like 20 seconds, then you remove the paper clip, and then start the car. Also make sure that the throttle body has been cleaned thoroughly with GumOut and a toothbrush....no carbon deposits should remain. Do not use a wire brush or sandpaper, use your finger or a plastic bristle brush. Nothing that gouges the bore of the throttle body should be used. -Chris

[ctaylor2]

Thanks again Chris

This information is great but I have another question?
This car has sat for a entire year and I was wondering if it could also be the Fuel injectors are pluged and can U clean these out yourself if so how would you do this?

Asking for more HELP!!

Thanks

[SpitAndDirt]

Er....yes and no. You should have one injector if you have a 2.5L but if you have multiple injectors, you have a 2.2L, there may have been a typo somewhere. Injectors can be removed, but as for cleaning, the best thing I can recommend is to let those injectors soak fully submerged in a small tub of gas overnight. That could loosen any stubborn deposits in it. You can also take a 9 volt battery and connect the two terminals of each injector to the battery and listen for clicking. This simple test will tell you if you have an bad injector. Pressure cleaning can not be done with out investing about $300 to Snap-On for a special fuel injector pressure cleaner tool.
One thing that I should mention is the possibility of low fuel pressure caused by a sticky fuel pump. You would need a fuel pressure tester to do this. If you have Multiple injectors you should have about 50psi of fuel pressure. If you only have one injector you need only about 10psi. You could also remove your fuel line and make sure you are getting clean fuel through. You should be able to have a helper turn the key on, and the pump will turn on for about 2 seconds. Turn off, wait about 5 secs and repeat. Attach a hose to the end of the main fuel line and pump out about a quart of gas and examine the quality. Change out the fuel filter($8) too while your at it. Other than the fuel issue. Check your vacuum routing diagram under the hood(hopefully its still there) and trace down hoses. Look for major vacuum leaks which will cause all sorts of problems. If you say it runs except at idle, I would seriously lean towards vacuum lines. Especially the one to your MAP sensor which I already mentioned in the previous post. This should give you more than enough possibilities. Enjoy! -Chris