Cleaned IAC Valve, reinstalled, now stalls when I let foot off gas

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Hockman59

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Hi - 95 Jeep YJ, I removed IAC valve and cleaned with brake cleaner, let dry, and reinstalled snug with o-ring - seemed to connect ok. Now when I start car and let foot off gas, it stalls. Did this twice. Did I damage the part? checked connections around the area.

thanks
 
I cleaned the port, wiped off, and now it is working thanks. Made sure I did not tighten as tight - the plunger on mine looks "longer"than the plunger on the replacement IACV that I see at the parts store for this Jeep. But thanks, it is idling and stays running. <SOLVED>
 
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The plunger is not a fixed length. It extends and retracts as necessary to provide the idle the PCM wants to see. If it's extended too far, it will stall because it will block the idle air inlet. My guess is cleaning it got some crud in it which hindered it's ability to retract. The second pass of cleaning and wiping you did may have cleared that up.

It's a weird device. They're pretty reliable, but you also have to be careful with them. I broke mine when I cleaned it and had to get another one. I went with one from O'Reilly and eventually bought a new Mopar one later. I think those are all discontinued now though. When I got the new one from O'Reilly, it was really short. Idled at 3000 rpm. Every 20 seconds or so, it would extend a bit more and cut the rpm by 300 or so. After a few minutes it was finally down to idle rpm. I couldn't install it at night like I wanted/needed to because I was afraid to wake my apartment neighbors with how loud 3000 rpm was, and I didn't know how long it would stay there.
 
I like that green YJ. Anyway, here is a pic of my cleaned up IACV at rest the plunger is extended - my thought was just to put in a new one, but I want the one that will operate smoothly. Your O'Reilly's story gives me a scare. My confidence in the cleaned up IACV here is about 50%...

IACV.jpg
 
I use throttle body cleaner over carb cleaner, only because they say carb cleaner is bad for the oxygen sensors (hence why it’s for carbs only). But I don’t know for certain on that. Same gist though.

Brake cleaner is definitely not the right choice for this task.
 
Used brake cleaner. Certainly got the part spic and span. Followed YouTube advice... from some fellow that worked on same Jeep as mine. One day in, the Jeep seems to Idle ok.
 
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also at FSM says in the book do not try to adjust it. (due to CJ5 actions done back then, but not here)
it is a stepper motor driven IAC (spins) not the common Solenoid type. (FSM chapter 14)
clean the IAC with plastic safe cleaners only.
CRC brand sells some.
make sure it is the right IAC for this car and exact year.
95YJ, 2.5L is.
old jeep P/N
4798376
screw sizes #10-24tps x 0.5. (SAE not metric) for IAC, day1 new may be locktite used. Torx.

the other 2 engines use different part # IAC

same chapter 14 it tells not to adjust the idle TV stop screw. (factory set) all Ive measured are 0.0005 to 0.001" gap., FYI
 
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many cleaners made are NOT plastic safe. (vast types, made for decades, and mutated greatly as EPA laws on EVAP VOC rules went into effect.
make sure the silly can says plastic safe.


www.crcindustries.com

CRC® Throttle Body & Air-Intake Cleaner, 12 Wt Oz

Over time, carbon, varnish, and gum can naturally build up on a vehicle’s throttle body and throttle body bores. This can lead to an assortment of engine issues, including a loss in fuel economy, rough idling, stalling, or a glowing check engine light. CRC Throttle Body & Air-Intake Cleaner is...
www.crcindustries.com www.crcindustries.com


the old cans of cleaner, in the shop 10+ years old and banned now (don't use them on electric parts)
have
perchloro-ethylene (a.k.a. tetrachloroethylene) and methylene chloride.(also used in paint stripper)
 
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