Cleaned TB, now engine revs up and down!!

[paulkramer]

OK, OK, enough bickering about Cobalts and Bonnevilles.......I need some help (technical) here!

I cleaned my throttle body last night with Valvoline TB cleaner. Put everything back together properly, and drove over to my favorite park and back. Car drove as usual.

Until this morning. I fired the beast up and the idle speed was about 2,500!! Then as I drove away, I noticed that there is now a lag after letting off of the gas before the engine speed drops. And when the car is in neutral, the engine revs up and down between 1,500 and 3,000 by itself!!

Anyone have any advice? What did I break!!??

[Cliffnotes69]

Sounds like a vacuum leak, double check vacuum hoses that were disconnected. If you took the TB off, check that the gasket is aligned properly and that the gasket didn't break. Are you sure everything is tightened down. Is the check engine light on?

[paulkramer]

The cel just came on a while ago. I checked all the connections - even the ones I didn't loosen. No, I didn't remove the TB, just the air intake hose that attaches to it. I reconnected that little sensor that sits in that hose, and the little breather/PCV/whatever hose that runs from that intake hose to the engine.

Guy on clubrsx thinks I gunked up my Idle Air Control Valve....seems it sits at the bottom of the TB........

[RSX-S777]

Could be the o2 sensor or TPS. IAC problem would seem to fit too, though. You don't seem to have very good luck with your maintenance projects, Paul.

*cough* airbox*cough cough*

[paulkramer]

I know, I know. Good thing I'm not a mechanic! If only I could make a living at having a green thumb.......like some people...

But FYI - I was at my friendly Acura dealer last week and I asked the tech about the airbox breather neck. He said he broke the first one he worked on too! Made me feel a bit better!

So, have any of you guys cleaned your IAC? I have considered spraying TB cleaner into the TB while the engine's running but am afraid to remove the air intake tube since there are other sensors that will be affected.

Any suggestions/experiences with this?

[RSX-S777]

I don't know if I'd do it with the engine running. Found this for you:

procedure:
1. locate the IAC and remove the 2 gold 13mm bolts...

2. pull off the IAC...and DO NOT REMOVE THE RUBBER LINES UNDERNEATH.

3. get your throttle body cleaner, put the straw on and spray the screen. (dont spray too much- just 2 shots).

4. use a q-tip and gently wipe away the black goo....use another one when it gets black.

5. use a flathead screwdriver and gently edge the screen to get the surrounding gunk off.

6. the screen should be pretty silver

7. spray some throttle body cleaner into the holes that go into the IAC...let evaporate for 10 minutes

8. clean the rubber ring with a rag and replace the IAC

9. when u start the car make sure that u revv the car to get the carbon buildup out that the throttle body cleaner took out.
---
you should notice a difference in driveability. for a while, push the car to its limit to get carbon out...

***problems?***
if you notice a low idle, you may have taken off the connector on the IAC (the black thing).

if your car idles abnormally, the IAC is still wet...rev rev rev...let idle to dry or turn off and let dry....it shouldnt last long.

adjust idle as well. then go ahead and reset your ecu.

Good Luck!

[RSX-S777]

It occurs to me that if your IAC was wet after you cleaned the TB, that may have caused the abnormal idle. Has it "fixed itself" through daily driving yet?

[paulkramer]

No, it hasn't gotten better yet. Apparently everything was fine when it was wet (I drove it to a nearby park after cleaning the TB - about a fifteen minute drive from here and then returned home after the car sat for almost an hour), and then as it sat overnight, the gunk re-formed on/in the IAC.

Thanks for that info. I assume that was RSX specific.......trouble is the IAC is underneath the TB and I don't see how I can remove it without removing the TB. Also concerned about removing either IAC or TB and attempting to reuse the original gaskets as they frequently won't go back on properly, especially after 50K miles of use.

[paulkramer]

I think I spoke too soon with my last post. I just drove to the store and back, and it seems to be improving!! Hallelujah!!

I did put a bottle of Seafoam additive in the tank last night; maybe that helped.