Idle Air Controller

[Chad Hendrix]

All, I need some help with my 1997 GTS. My IAC is starting to fail. I have tried cleaning it as described in may different posts and it does not seem to really help. The number on the side of my IAC is 5245352. I have tried to purchase a replacement 5245352 several times now and they are all too short from the flange to the tip of the plunger. I read on forums that 53030657 and 4778637 can be used as a replacement. I ordered one of each to try but it is also too short. See the attached picture. The one on the right side is my stock one. Does any one know what part number I should order to get the longer version I need? Thanks.

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[MoparMap]

Do you know if the ones you're buying are fully extended? They may not ship that way, so without actually powering it up I'm not sure you can tell how long it really is. You might be able to pull on it and extend it, but that could be asking for trouble.

 

[Chad Hendrix]

Good point. I never thought to try that. I will give it a try later today. I will feel totally stupid if that is all it is.

 

[MoparMap]

I know a DRB III can set idle position, but in lieu of owning one of those I think you can just plug it into the car and turn the key and it may cycle it all the way in and out as a system check. Not 100% on that, but can't hurt to try.

 

[Chad Hendrix]

Tried at lunch and there was no change in the length once I hook them up and turned on the ignition. I gently pulled on each and again no change.

 

[MoparMap]

Hmm, I know it would likely do something if you start the car, but not sure what the PCM will think of that. Probably wouldn't hurt anything, but you'd have a pretty high idle for a while. Maybe try when the engine is warm already so it's not idling super high on first start.

 

[Chad Hendrix]

I did not try that with the two I have now. But, the first one I got I installed and and let it idle and warm up. it just idled at almost 2000 rpm.

I tried reaching out to several viper stores and the only one that has responded so far is Roe Racing. They say that the part number I have is from a 2005/2006. So, i might try to order that from them. I bought the car about a year ago. I thought it was stock. This might have been changed to a newer version, but the aluminum elbow piece it mounts in would have to be change too to make it work. Never know what some previous owner might have done. I am the third owner.

 

[MoparMap]

If I remember correctly, I thought there was a learning process the car had to do with an IAC to set the position, but I don't recall off the top of my head exactly how it worked. I know that there is a "minimum air flow" routine that the car does to determine idle position, but I don't know if there is a way to force that or not. For instance, recently after my rebuild whenever I'd put an updated tune in the car, it would drag way down or even die whenever I came to a stop after coasting down a bit. Over time the car learns where the IAC needs to be to maintain minimum airflow to keep the engine alive. I'm not sure there's really any way to force learn that though as it's different from just idling the car.

 

[Chad Hendrix]

Yes, there is a process for it to reset. The way I understand it, you drive the car for 10-15 miles with the AC on. Stop, let it cool down. Then repeat 4-5 times.

I have done this process several times after replacing the battery/disconnecting the battery. I did just do some mods, including replacing the cats with HF and installing a 3” Magnaflow exhaust, new radiator and thermostat, plugs, wires and coils. After that, I installed a new tune using the SCT tuner and the tune I purchased for these mods. Maybe it has something to do with the tune itself. I will try removing it and seeing if there is any change.

 

[Chad Hendrix]

Well, good news! The problem is now solved. So, here is a rundown of has happened since I last posted.

Talked to Dan Cragin at Specialty Performance. During the discussion, he mentioned that an deal tool would should be used to adjust the IAC to get the idle close enough so that the self learning would work. Since I had a new 4778637 IAC that I could not return, I decided to pull a little harder on the plunger than I had previously. When I did the plunger moved sufficiently that it was almost the same length as the one off my car. I installed the new one and then did as Dan suggested and let it idle for 5 minutes with the AC on. First time it was still a bit rough and had a hard time recovering after reving it. I let it cool, then did the same 3 more times. Now, it runs and idles flawlessly.

While one could easily damage the IAC doing what I did, it worked for me. Since I did not have access to the factory tool needed to adjust the IAC electronically, this alternative can work as long as you are careful to not over extend it and not pull too hard.

 

[Steve-Indy]

Thanks for the followup, Chad!!

 

[ViperRed]

Happy ending, good job!

 

[Chad Hendrix]

Strange it was soooo hard to get to this point. Maybe if I had let it idle longer and/more times it would have eventually adjusted itself. But, got lucky, did not damage the IAC and it is back running great just in time to put it away for the winter.