IAC Error 35 - My own worse Enemy

[thedarkshadow]

Well with the warm weather I finally got around to chasing down my Error Code 32.
I had a feeling the error was from a vacuum line as back when I did my tune-up I noticed they were looking pretty sketchy. Well I follow the 1/8" vacuum from, what according to one of Chevmaher's posts is, the cruise control to a T that heads down to a 7/32 line and then goes way the heck down to the front of the van to a mysterious ball. Well the whole line of vacuum line is rotted and pretty much crumbles in my hand and even better the 2" of 7/32" line goes nowhere. After a bit of searching I find it goes to a nipple not far off from the front passenger side of the throttle body. I've replaced this entire run...pull the battery to clear the codes...start her up and voila...rough idle is gone. Turn it off and even better no more error code 32. I figure woo hoo...the idle might be a bit high but great!! So I proceed to pull the d/s dummy PCV valve and put an actual valve in...vent both PCV valves under the van and run a line of vacuum line from the front to the rear of the throttle body to replace the lines that use to go to the pcv valve and the d/s valve cover. Van runs great seems nice and peppy. We take a run to the store leave it idling and grrr....engine light comes on. So we kill the van...check code and les voila...error code 35... IAC problem or idle error.

Any and all thoughts from the peanut gallery would be immmmmmmmmensly appreciated....

Thanx so much,
Dan

[mkj54]

Have you tried taking the IAC valve out and cleaning it and the passage it sits in?

[thedarkshadow]

Nope I haven't had a chance to pull the IAC out and check it out. I went through and double checked the vacuum lines that I could find...found another bad one down at the vacuum accumulator magical myster ball...replaced it and....

nope...

same thing....



even better...code 32 is back.....

If I have time tomorow I'll pull the dog house off again and check the IAC and what ever other connections I can find.

If anybody has any other suggestions it would be immensly appreciated. Man I wish GM had come up with a better system to get in and out of the back end of the engine....

Thanx...

[mkj54]

Let's start over, 32 is for EGR and 35 is for IAC. Both can be taken out and cleaned. Either one can effect idle speed but I can't recall a vacuum leak giving me these particular codes.

[Leeann_93]

The magical mystery ball is your vacuum reservoir, by the way.

Code 32 is indeed EGR, not IAC. Get a screened gasket from the Dorman/HELP! section of your LAPS, pull your EGR valve, clean the pintle and seat, clean the bore it rides in, then reinstall with the screened gasket.

You'll need a 10mm socket with at least 9" of extensions and a 10mm wrench, preferably ratcheting (easier). This you get to from the hood, not the engine cover.

[thedarkshadow]

Yippers I realize the code 35 and code 32 are totally different animals on two different systems. I may have jumped the gun and not explained that well enough. Ages ago I had the light come on for the EGR system and didn't have time to check into it. I had figured when I did the tune up and went back in the second time and noticed a loose vacuum line and several rotted out vacuum lines that I assumed triggered my code 32. Also, the light isn't on all the time. Once a week give or take for no apparent reason the light will come on while driving. When we turn the van off and check we would find the code 32. Turn the van off and on...and light gone. That's why I went in and changed over a wack load of vacuum lines. As for the code 35 that was new...and seems to come on anytime we idle in gear now. Prior to doing this I had no Code 35. But I did have a rough sporadic idle which I attributed do the vacuum lines. Now she idles pretty nice...wish I had a tac as I think it's a bit high....but nice.
Anywho...enough history....I finally had a chance to have a look at this again today...and succesfuly removed what I thought was my IAC valve to clean it out and check it. Apparently from what I found online....I succesfuly removed my TPS....d'oh!!!!!! Would someone be so kind as to point me in the apporximate direction of where the IAC might be??? *lmao*

Thanx so much...

[Leeann_93]

IAC is on the passenger side, almost opposite the TPS. Also has 2 Torx screws holding it in and one electrical connector.

[thedarkshadow]

Funny the TPS on mine was on the passenger side....this is the tps isn't it??

When this didn't seem right I popped these numbers...

...into google and it seemed to lead me to beleive it was the TPS.

[mkj54]

Yup, that's the TPS. The IAC is right next to it, just to the left in the picture, the big nut looking thing. It's takes a 1 1/4 wrench and unscrews out of the throttle body.

[Leeann_93]

Odd. Mine is the thing on the right in this pic, held in by 2 Torx screws. This is on my Bravada, but my Astro is the same.

[thedarkshadow]

Who'd a thunk it Leeann....I should've of thought of this first and to check Autozone as they give pics. Apparently if you have CPI you have 2 torx bolts and the style of IAC that you have. If you have the TBI you end up with the animal I have with the 1 1/4 hex head. I never even thought there would of been a difference....man and the difference in price...24.99 for mine compared to 45.99 for yours....OUCH!!! and that's in US $$!!! To buy the same part for mine in Canada at Napa is 82.99....super ouchy!!

[Leeann_93]

I never thought you'd have a TBI (rare in '94). Sorry...