Well in my frustrating saga to find out why I have a rough idle and a mifire code, I took off the IAC sensor, or at least I THINK it was the IAC sensor.. I took the barrel and tip off, cleaned real good and then out it back together and reinstalled it. It didn't want to go all the way in, probably had a couple millimeters to go so I just tightedned it down and sucked it down witht he screws.. I started it, ran REAL rough, gave it a little throttle, heard a loud pop, turned it off and wenrt to restart it and now it wont start at all, it just cranks.

will a bad (or broken) IAC cause a no-start?

And if I go to Autozone, what is it called? Intake Air Sensor?

 

Very much so. In rebuilding the top end of my 4.0 i thought it would be a good idea to clean the iac stepper motor too. After i did so, i installed it and she just cranked and cranked. I bought another on and reinstalled it, it fired right up. It still had a little bit of a rough idle, but i relearned the pcm and it cleared up. To relearn, leave the positive batt. Cable on the batt. And disconnect the neg. Cable and touch it to the pos. While still connected to the batt. Hold it for 30 sec. Do this before starting it, but after replacing the iac.

 

Oh...it's called the idle air control sensor idle air stepper motor

 

i thought you were supposed to remove both cables and then touch them together. am i wrong? or is it different with jeeps? It just sounds like that may cause the battery to explode. I could be wrong that is why i am asking.

 

No....it wont explode. Just make sure you remove the neg. And leave the pos. On. Touch the removed neg to the (still connected to the batt.) posi.

 

If you jammed the iac in you may have possibly shorted the sensor(this will shut down the pcm) Try unplugging the iac and hold the throttle part way open. If it still doesn't start check all of your fusses

 

Let me know if you have any more questions
you must do that after replacing the iac

 

well Autozone sold me the wrong one, and I was able to push the plunger back into the old one and get it started with a little help from the gas pedal during cranking, but I have a feeling that it might be bad so I am off to the pick and pull to find a replacement.

 

should I do the same to my xj it is a 1990.

 

ya i have a 1990 xj also.. and i have a high idle and i was told to take the iac off and clean it to.. should i not bother and get a new one?

 

Thanks. $45 part screws up the whole day. Bout go do mine tomorrow

 

When you clean it don't unscrew the end. Just use a toothbrush and throttle body cleaner. Be really gentle with it and you won't have a problem. And just a suggestion you might as well take the whole throttle body off and clean that too. Don't use carb cleaner as it is too harsh. Only use throttle body cleaner.

 

What about a new one? Same process with the battery?

 

I'm gonna step up to the plate and say this about the computer. Take the positive cable off the battery and ground it. This will clear any voltage from the system, thus resetting the computer.

 

X2 you are playing with fire if you try to take the end cap of the IAC.

Taking off the throttle body will give you access to clean the whole thing. Just when you take it off be sure to plug up the rest of the intake with something so no debris gets inside your motor! (try to use something that won't give any dust/debris off, use a ziplock baggy or something)