Hi Ben! You can assess how the IAC is working by using a high end scan tool to show the position of the IAC motor. Look for a data pid showing "IAC counts". You'll have to sort out whether the data pid is desired IAC or actual position. If the IAC has failed and the problem is low idle, I would expect that data pid to be out of range, suggesting the PCM is trying to open up more. During a vacuum leak the IAC should respond by closing down, so you can watch the PCM respond in real time by creating a vacuum leak (or likewise restricting air flow somehow) while watching the IAC counts on the scan tool to see what happens either way. You might even be able to feel it move, though it's just a tiny stepper motor on a worm drive. If you can't feel it move I suppose you could remove it during a test, tape off the hole, and watch for rotation of the piston. They rarely fail, but what often happens is you get carbon buildup near the throttle butterfly that reduces air flow when the butterfly is closed at idle. Then the IAC responds by opening up, with increased counts to reach target rpm. As you say, new cars monitor the circuit, triggering a code if circuit integrity is wrong or it doesn't seem to respond.
That is the totally awesome technical way to check on its operation. It’s also fairly cheap to purchase, so as I was diagnosing my idle issue I replaced it with one from a parts car and had no change in operation. If I hadn’t had a parts car it wouldn’t have been too expensive to replace. I always kinda wonder who purchases the “economy” parts on rock auto, the ones that are really cheap, but now I see the merit of those parts if you are looking for a cheap way to test things.
My car starts but dies immediately after. Codes that pull up are centered around air flow. Could the idle air flow sensor be the reason it dies? I have cleaned the mass air flow sensor and has a newish air filter. This just happened after taking my air filter housing out to do a radiator replacement and now it won’t stay running. Looks like as soon as it starts up it’s running at 1500 rpm then drops to nothing and dies
The best way to test the Mass Air Flow sensor is to unplug it. The MAF sensor can mess up things quite a bit but goes into default mode when its gone. After that check and nothing changes, see if you can keep it alive with some throttle, not WOT, but some, if it runs then its the idle air control motor, and that needs to be replaced.
![ILLSLICK - WINTER IS COMING [Official Video]](http://i.ytimg.com/vi/dwTMeM1zIhQ/mqdefault.jpg)
Hi Ben! You can assess how the IAC is working by using a high end scan tool to show the position of the IAC motor. Look for a data pid showing "IAC counts". You'll have to sort out whether the data pid is desired IAC or actual position. If the IAC has failed and the problem is low idle, I would expect that data pid to be out of range, suggesting the PCM is trying to open up more. During a vacuum leak the IAC should respond by closing down, so you can watch the PCM respond in real time by creating a vacuum leak (or likewise restricting air flow somehow) while watching the IAC counts on the scan tool to see what happens either way. You might even be able to feel it move, though it's just a tiny stepper motor on a worm drive. If you can't feel it move I suppose you could remove it during a test, tape off the hole, and watch for rotation of the piston. They rarely fail, but what often happens is you get carbon buildup near the throttle butterfly that reduces air flow when the butterfly is closed at idle. Then the IAC responds by opening up, with increased counts to reach target rpm. As you say, new cars monitor the circuit, triggering a code if circuit integrity is wrong or it doesn't seem to respond.
That is the totally awesome technical way to check on its operation. It’s also fairly cheap to purchase, so as I was diagnosing my idle issue I replaced it with one from a parts car and had no change in operation. If I hadn’t had a parts car it wouldn’t have been too expensive to replace. I always kinda wonder who purchases the “economy” parts on rock auto, the ones that are really cheap, but now I see the merit of those parts if you are looking for a cheap way to test things.
love watching your pontiac grand prix maintance videos.
Awesome! Thanks for watching. Replacing a CV boot is next.
Thank You,Thank You, Thank you!!!! I needed this video bc I don't have anyone to help lol.
Yeah, my car has quite a few things replaced.
My car starts but dies immediately after. Codes that pull up are centered around air flow. Could the idle air flow sensor be the reason it dies? I have cleaned the mass air flow sensor and has a newish air filter. This just happened after taking my air filter housing out to do a radiator replacement and now it won’t stay running. Looks like as soon as it starts up it’s running at 1500 rpm then drops to nothing and dies
The best way to test the Mass Air Flow sensor is to unplug it. The MAF sensor can mess up things quite a bit but goes into default mode when its gone. After that check and nothing changes, see if you can keep it alive with some throttle, not WOT, but some, if it runs then its the idle air control motor, and that needs to be replaced.
Yeah mine idles high at 1.5k rpm’s even idling at a light shit goes high
Really sounds like a vacuum leak.
What if my car stop brand new battery n it only start with a jump.cud it be this or ground wires n .I do have a 2002 grand prix
Could be bad ground, bad battery connection, at the battery. If it’s not cranking but has voltage, it’s a connection somewhere.
@@Turbo231 so mean I should just get electrical diagnostic.it just hve to be jump n want regular start n started out the blue
@@MsBrivlogs1 Yes, something is not connected well. General hard grabbing and shaking of the cables might provide clues.
Is it the same location on a 06 grand prix
Not sure, that’s going to be a series 3 3800, so it might be but I’m not 100% sure.
How much mpg are you getting? I am getting 16 mpg mixed mostly city with some highway. DO you think something is wrong with my car's mpg?
I average 22.8, there is a lot of highway on that. 16 is pretty low, I’d look at maybe getting a tune up.
@@Turbo231 Thank you, will do it.
My 2003 grand prix gt runs high at idle
Idle air control or a vacuum leak can cause this issue. Check for an SES light for a vacuum leak or any hissing in the engine compartment.