IAC needs replacing?

[jayeljeep]

Hello all, here’s one for ya... Replaced TPC. Ran great, still is, but after a freeway drive, speeding now and then, everything felt great. Then quick traffic jam, downshifted, then up shift but accidentally went from 2 to 5, engine sputtered, then erratic idle. Idle dipped so I exited, got to a stop and it died out. Heavy foot on the gas on the pedal to keep it from stalling at stoplights. Then ran ok, but now there’s a noticable, single, whole car jerk in 2nd and 3rd gears only, where there wasn't before. I was about to replace the IAC, but I just unplugged the hold one along with the new TPC and ran great. After researching cleaning and replacing the IPC, im thinking thats it. But Im a newbie to this, so advice and pointers please. Much mahalos gents. BTW, I got another question about a possible throw out bearing issue.

 

[TJ Jim]

TPC ?
IPC ?
Help me with the acronyms.

 

[hear]

I'm guessing TPC ==> TPS, throttle position sensor
IPC ==> IAC, given that he mentions cleaning it.

 

[TJ Jim]

I'm guessing TPC ==> TPS, throttle position sensor
IPC ==> IAC, given that he mentions cleaning it.

I suspected that but wanted to clear up and hopefully make sure we’re talking about the same things. I’d agree on leaning the idle air control again. But the five to two shift is strange? Or two to five down shift? Just a bit confusing

 

[jayeljeep]

TPC ?
IPC ?
Help me with the acronyms.

Damn, Im so dumb at this. TPS- throttle position sensor.. IAC- Idle air control.

 

[jayeljeep]

I suspected that but wanted to clear up and hopefully make sure we’re talking about the same things. I’d agree on leaning the idle air control again. But the five to two shift is strange? Or two to five down shift? Just a bit confusing

Sorry for confusion. I went from 2nd gear and then, looking for 3rd, I slipped into 5th. she bogged down, shook like crazy then, i got 3rd gear and was feeling a lag in throttle. I exited the freeway and pulled over and she stalled.

 

[TJ Jim]

Damn, Im so dumb at this. TPS- throttle position sensor.. IAC- Idle air control.

Not dumb!!! Just learning. That’s the fun part

 

[macleanflood]

Did you clean the IAC orifice in the throttle body? You mentioned cleaning the sensor...but did you clean the throttle body?

Thread 'How to clean your IAC (Idle Air Controller) valve'

Jan 2, 2016

If you're experiencing idle issues on your Jeep Wrangler TJ the most likely culprit (and the first thing you should check) is your IAC (Idle Air Controller). Often times the IAC gets very gunked up causing the Jeep to idle improperly. A simple cleaning is usually all it takes to get it running as good as new.

If you end up needing to replace your IAC valve (they do fail on occasion), you can find the part numbers (and the links to purchase them on Amazon) below:

2005-2006 IAC Valve (Part # 4861552AC)
1997-2004 IAC Valve (Part # 4874373AB)

There is no need at all...

• Chris
• iac idle idle air controller idle valve
• Replies: 195
• Forum: TJ How-to Guides

• 

-Mac

 

[jayeljeep]

Did you clean the IAC orifice in the throttle body? You mentioned cleaning the sensor...but did you clean the throttle body?

Thread 'How to clean your IAC (Idle Air Controller) valve'

Jan 2, 2016

If you're experiencing idle issues on your Jeep Wrangler TJ the most likely culprit (and the first thing you should check) is your IAC (Idle Air Controller). Often times the IAC gets very gunked up causing the Jeep to idle improperly. A simple cleaning is usually all it takes to get it running as good as new.

If you end up needing to replace your IAC valve (they do fail on occasion), you can find the part numbers (and the links to purchase them on Amazon) below:

2005-2006 IAC Valve (Part # 4861552AC)
1997-2004 IAC Valve (Part # 4874373AB)

There is no need at all...

• Chris
• iac idle idle air controller idle valve
• Replies: 195
• Forum: TJ How-to Guides

• 

-Mac

I have not cleaned the Throttle body. I know I should after watching videos of that. as soon as gaskets are involved, I get a little nervous. I replaced a head gasket on my 78 Datsun 280Z and blew it out because I didnt do it properly. Mixed fluids, white smoke, overheating all kinds of crap. Been iffy since then. But, Im gonna do it. Only thing, the air intake tube seems to be frozen or fused onto the throttle body.

 

[JKP]

Just spray throttle body cleaner in the IAC slot with the throttle body in place. Or you can remove just the IAC, my 06 just has an O ring on the IAC. If you remove the IAC cover, I'm not even sure you can buy that gasket. The throttle body to intake gasket should be easily available if you do take it off, I've never took it off on the YJ or TJ.
.
You just have to pull and twist on it to break it free.

 

[jayeljeep]

Just spray throttle body cleaner in the IAC slot with the throttle body in place. Or you can remove just the IAC, my 06 just has an O ring on the IAC. If you remove the IAC cover, I'm not even sure you can buy that gasket. The throttle body to intake gasket should be easily available if you do take it off, I've never took it off on the YJ or TJ.
.
You just have to pull and twist on it to break it free.

Mahalos JKP. Ill try it. sorry for late response. so far its running great. just to confirm, I take the IAC off and spray directly into the IAC reciever? I havent taken IAC off yet but Ill try it soon as I come up for air. Cheer dad here and my daughters got my time twisted. quick question, can you post quick time movies on here? have a video that shows weird sound when clutch is in neutral. From a youtube search it may be a “throwout bearing”. Thanks again gents. All your advice for my idiot questions are truly appreciated.

 

[JKP]

You can try spraying in the slot in the throttle body first.

If that doesn’t clear it up, you can just remove the IAC. You may need a new oring for it if it gets damaged coming out.

You can post links to videos on YouTube, etc.

 

[jayeljeep]

hello gents, sorry for the lag. Had another idle drop incident. so I pulled out the IAC, cleaned it and in the process, broke the PCV vent spout. Fixed that along with cleaning the IAC, (it didnt look that dirty-see attached pics) some crud came off but it makes me wonder why that would affect the idle to that extent. That said, shes running great. but still wondering when itll happen again. One thing I noticed, it happens after Ive taken the Jeep on a long freeway drive- 30 mile there. rest for 5-6hrs, then 30 miles back. Steady speed and nothing crazy. This has happened 3 times, all 3 were similar driving events. Any ideas? She runs great now, just wondering if itll happen again.

 

[GoldenGorilla]

That was what I saw with mine despite several cleanings. Except I'd get a severe throttle hang at 3000 rpm. I replaced it. Then discharged the PCM to force it to relearn. The factory IAC was very stiff. Wouldn't move in or out by hand. Replacement has a good amount of resistance, but moves. Have not had a hang since.

 

[jayeljeep]

That was what I saw with mine despite several cleanings. Except I'd get a severe throttle hang at 3000 rpm. I replaced it. Then discharged the PCM to force it to relearn. The factory IAC was very stiff. Wouldn't move in or out by hand. Replacement has a good amount of resistance, but moves. Have not had a hang since.

Do you have to discharge the PCM every time you replace or clean the IAc or TPM?

 

[hear]

Do you have to discharge the PCM every time you replace or clean the IAc or TPM?

nope. But I also spend enough time with my battery disconnected that I'm never too far away from resetting the sensors anyway.

 

[jayeljeep]

nope. But I also spend enough time with my battery disconnected that I'm never too far away from resetting the sensors anyway.

should I reset the PCM? Ive replaced the TPS and cleaned the IAC.

 

[GoldenGorilla]

Do you have to discharge the PCM every time you replace or clean the IAc or TPM?

Not when you clean, but when replacing with a new IAC it's a good idea so that it resets the stepper motor position calibration.

 

[hear]

Not when you clean, but when replacing with a new IAC it's a good idea so that it resets the stepper motor position calibration.

I'm 98% sure it self-calibrates either by fully retracting or extending till it stops....in either case it counts turns to figure out the airflow.

This is where somebody screen grabs the FSM page and demonstrates just how little I know.

 

[jayeljeep]

@hear @GoldenGorilla so should I buy a new IAC? I just cleaned it.

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