Propper Throttle body adjustment (INCLUDING IAC) WITH PICS!

[Tipsy]

The OP mentioned poor fuel economy as one of the driving reasons behind this initial write up, can the IAC effect mileage that drastically?

 

[amalik]

Nice. I would also have used to compressed air to blow out all the ports and passages in the TB while I had it on the bench--removing those silly dead end rubber tube caps to do it. This is what the FSM says to do. Since you sand blasted it, this is a must IMHO. I am an antique tractor guy first, and tractor guys never sandblast a carb, they bead blast them. TB ports/passages aren't as critical, but I'd sure want to get those little sand grains out of there so they don't go anywhere else.

The FSM also says never to spray anything into the IAC port when cleaning the TB, for just the reason you mention. I have avoided doing that since new, and so far my IAC works fine. (12 years and 140k). I clean the rest of the TB every 30k, including blowing out the ports/passages.

So then Durk, you've never had or seen a bunch of gunk in your IAC?

 

[TheDurk]

So then Durk, you've never had or seen a bunch of gunk in your IAC?

No one has. It has never been opened in 19 years. The TB has never even been off. I just clean it in place. Maybe I should credit my regular Techron treatments but I don't see how those could affect the IAC as it doesn't see fuel.

As long as it continues to idle perfectly, I won't open or clean it.

 

[Sand and saltwater]

I have tested my IAC as described above,and it opens and closes fine. The problem I’m getting is the IAC is chattering. When I checked the voltage at the connector ,it’s 11.8 on both sides at the same time . Any ideas would be appreciated

 

[jasonochs25]

So, I went through this thread twice...Did I miss where the adjusting part is? Twice? The title says Propper (proper?) TB adjustments and was hoping to find a thread on the cable adjustments. Hmmm. What am I missing here?

 

[AgeOfOctane]

I just wanted to say thanks for this post. Mine had seized up on me and I was having some high and erratic idle issues. In my case I was able to free it up by pushing it back and forth and cleaning the valve with a tiny stainless steel brush (meant for a dremel). After it started moving a little, I tapped it with 12 volts back and forth and it eventually freed itself the rest of the way. I was able to do the same thing on a Honda about 5 years ago and it's still idling smooth.
Also, a 1/4" impact driver will make short work of those soft screws. Just use firm pressure and be gentle with the trigger.

 

[mtbtim]

Since [MENTION=102606]infamousRNR[/MENTION] and I have a video on this subject, I figured it made sense to post it in this thread for others to find. Happy Wrenching!

<iframe width="560" height="315" src="https://www.youtube.com/embed/agIRNNA-6cs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[Letters4taylor]

Any updates on that autozone iac?

pm me if you've got any questions, good luck

How is that iac from autozone holding up.
I’ve narrowed my rough idle down to iac, and would like to replace (limping along with my cleaned out factory one).

Thanks for the great write up.

 

[Bad Luck]

How is that iac from autozone holding up.
I’ve narrowed my rough idle down to iac, and would like to replace (limping along with my cleaned out factory one).

Thanks for the great write up.

Bill_Dunnigan hasn't been on here since December 2015. I wouldn't expect a response.

 

[pckl.it]

IAC replaced - still have a P0505 code

1999 4Runner, v6. Had a rough idle and P0505 code and I just replaced the IAC along with cleaning the TB and replaced the TB gasket while I was in there.

Idles beautifully now. Still have the code!

What do I tackle next? Vacuum lines? O2 sensors? Somewhere I read a short in the AC system can also cause the code, and my compressor died a few weeks ago.

But… clearing the code works while driving the car, and it stays off until I come to a stop. Which seems to indicate it’s actually idle related! But it’s a brand new IAC and I haven’t experienced any issues. Aaaagh.

 

[Bad Luck]

1999 4Runner, v6. Had a rough idle and P0505 code and I just replaced the IAC along with cleaning the TB and replaced the TB gasket while I was in there.

Idles beautifully now. Still have the code!

What do I tackle next? Vacuum lines? O2 sensors? Somewhere I read a short in the AC system can also cause the code, and my compressor died a few weeks ago.

But… clearing the code works while driving the car, and it stays off until I come to a stop. Which seems to indicate it’s actually idle related! But it’s a brand new IAC and I haven’t experienced any issues. Aaaagh.

Could be ECM (not likely) or the ac signal circuit (more likely). Here's a link for a 2000 FSM: Update your browser to use Google Drive, Docs, Sheets, Sites, Slides, and Forms - Google Drive Help It's not exactly the same as a 1999 but it should be close enough for what you need. I'll attach the diagnostic procedure for that code as well.