Cold starting and poor initial idle issue

RESOLVED! (for now)

After doing some more research I decided to pull the IAC and test before ordering an eBay cheapo

Pulled the throttle body, removed the IAC and tested the solenoid using a 12V DC transformer. Attached the neg to the center pin and tapped the positive lead on the top and bottom pins to see the solenoid function. As you'd suspect, movement was limited. The solenoid would open the gate, but could barely close it. Probably plugged with crud.

I sprayed out the barrel cylinder and chambers with TB cleaner. Using Q-Tips, patch cloths and a small screwdriver I scrubbed and scraped and tapped out lots of crud. Retested solenoid a few times along the way and repeated with soakings and cleanings until I was satisfied with the gate operation.

Cleaned up the gasket mounting surface of the IAC with TB cleaner and a light facing on some 400 grit sandpaper on glass to remove all the stubborn old gunk and cleaned again. Got FelPro gasket 61087 from local parts store for $2.29 to replace the old, swollen one and bolted the IAC back on the throttle body.

The moment of truth after everything was bolted back up and she fired right up and idled on her own! :dancin:

Thanks fellas
 
Less than 36 hours after "the fix" the car fails to start without me feathering the gas pedal *sad trombone*

I ordered an eBay IAC and will install it in the next day or two
 
I tried the cheap Ebay IAC. At normal temp, it would do well, but in colder temp, it would not hold proper idle, and would even kill the engine is very cold temps at start-up. This IAC is still in a basket of un-used parts.

I ended up cleaning my original IAC very good, and had to soak it in oil after the cleaning so it would stop sticking at cold startups. That means oil directly where the cylinder is.

My analysis is that the thick oil vapors/sludge coming from the valve breather tube come in directly into the IAC, which is at the base, and prevents its movement when cold. When the water temps rise, it heats up the IAC and movement is good again. With proper lubrication of the IAC, this does not happens.
 
diverscale said:
I tried the cheap Ebay IAC. At normal temp, it would do well, but in colder temp, it would not hold proper idle, and would even kill the engine is very cold temps at start-up. This IAC is still in a basket of un-used parts.

I ended up cleaning my original IAC very good, and had to soak it in oil after the cleaning so it would stop sticking at cold startups. That means oil directly where the cylinder is.

My analysis is that the thick oil vapors/sludge coming from the valve breather tube come in directly into the IAC, which is at the base, and prevents its movement when cold. When the water temps rise, it heats up the IAC and movement is good again. With proper lubrication of the IAC, this does not happens.
Click to expand...

Ironically, the car started fine this morning, cold for Southern California but not cold find National standards.

I will install the eBay IAC and see how it goes and spend more time detailing my factory IAC as you recommend.

I wonder if some form of inline filter, although that would get clogged, would keep the IAC from being so easily fouled.
 
Received my eBay IAC but didn't have a chance to install it, still running the factory IAC that I cleaned up a week ago.

Went to Nevada this weekend, sub-freezing temps and the car started EVERY SINGLE TIME without me feathering the gas. Damn.
 
octanejunkie said:
After doing some more research I decided to pull the IAC and test before ordering an eBay cheapo

Pulled the throttle body, removed the IAC and tested the solenoid using a 12V DC transformer. Attached the neg to the center pin and tapped the positive lead on the top and bottom pins to see the solenoid function. As you'd suspect, movement was limited. The solenoid would open the gate, but could barely close it. Probably plugged with crud.

I sprayed out the barrel cylinder and chambers with TB cleaner. Using Q-Tips, patch cloths and a small screwdriver I scrubbed and scraped and tapped out lots of crud. Retested solenoid a few times along the way and repeated with soakings and cleanings until I was satisfied with the gate operation.

Cleaned up the gasket mounting surface of the IAC with TB cleaner and a light facing on some 400 grit sandpaper on glass to remove all the stubborn old gunk and cleaned again. Got FelPro gasket 61087 from local parts store for $2.29 to replace the old, swollen one and bolted the IAC back on the throttle body.

The moment of truth after everything was bolted back up and she fired right up and idled on her own! :dancin:

Thanks fellas
Click to expand...

Perfect and why this is such a great place for help and information!!! LOVE ME SOME T4R.ORG!!
 
Any update? I just cleaned two throttle bodies and IAC's. Testing both they opened fine but didn't close tight. Are they supposed to? My wife's rig is now idling at 300 RPM when cold and feels like it wants to stall. I adjusted the throttle cables as well but assume the IAC as the only likely culprit.

Sent from my SAMSUNG-SM-G890A using Tapatalk
 
mckennar said:
Now this is the kind of optimism I come to these forums for.


j/k good luck!
Click to expand...
Only because everyone says cheap China parts fail, eventually.

I have no doubt there is a vast difference between a $30 aftermarket part compared to a $200 Factory part.

In this case, not being a life safety like an LBJ I'm okay taking a chance.

Sent from my Nexus 5X using Tapatalk
 
tystaco said:
Any update? I just cleaned two throttle bodies and IAC's. Testing both they opened fine but didn't close tight. Are they supposed to? My wife's rig is now idling at 300 RPM when cold and feels like it wants to stall. I adjusted the throttle cables as well but assume the IAC as the only likely culprit.

Sent from my SAMSUNG-SM-G890A using Tapatalk
Click to expand...
I tested my factory IAC and the eBay IAC and neither of them close tightly, leaving a slight, open gap.

3 cold start since swapping it and each one a winner. Time will tell.

Sent from my Nexus 5X using Tapatalk
 
My low idle went away on its own...

I think after I cleaned it, a piece of debris must have been hanging out in the IAC...I saw a 2000 rpm idle Thursday night...ignored it. Following Saturday was the day of 300 rpm idle...then by Sunday and so far this week no issues.

I changed the ignition coils on both of my rigs and it cleaned up long crank starts pretty well. I know the Denso's are supposed to be lifetime...but 17 years is a pretty long electric lifetime. Got a set from Amazon for $50 for all three instead of $50 a piece...had good reviews. Time will tell.
 
octanejunkie said:
I tested my factory IAC and the eBay IAC and neither of them close tightly, leaving a slight, open gap.

3 cold start since swapping it and each one a winner. Time will tell.

Sent from my Nexus 5X using Tapatalk
Click to expand...

Just curious how things ended up for you? I'm currently having cold start issues and was debating on buying the Ebay IAC after I cleaned everything up and still having issues.

- Sean
 
Currently facing this issue. At the moment 8 out of the 10 times my 4runner starts normally but those 2 times I have to step on the gas for about 7 seconds so that it idles normally and doesn't turn off on me.

Do you think it could possibly be the IAC valve?

Looking to prevent it from getting worse.
 
Playing the 3.4L winter difficult cold start and won't idle game. Cleaned the IAC and replaced gasket, fuel filter clean. No other issues, runs great in Summer.
Considering another deep clean and oiling of IAC, maybe change the coil packs out.

Let ya know
 
for some reason the above links go no place for me.

But for the issue, I would clean the maf before cleaning the IAC again or replacing coil packs
 
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