I cleaned my car's idle air conrtol valve. after i installed it, i reset the ecu. when i turned on the engine it started idling very rough, almost like it was gonna shut off. What do you think the problem is? any ideas?

 

Perhaps you damaged the IACV during the pull/clean/reinstall.

Does the engine continue to idle rough or is it just on startup?

 

Your base idle may be set too low. You will want to check it. Checking base idle should be done anytime you mess with the TB or IACV and also if it's been a few years. Do you notice idle rpm dipping down?

 

it continues too idle rough after srtartup. at normal operating temp, it goes from 700-550 up and down continuously.

BTW: I started the engine by mistake to back the car up when all the connections were off. it started and shut down immediately by itself. If that helps.

 

Sounds like your base idle is too low. The ecu tries to correct it but it will waver between too low and normal. You likely through off your idle, especially if you adjusted the plastic screw on the IACV.

Alternatively, you may have a manifold leak. If bad enough, the car will run so rough that you would swear it is misfiring! Make sure all your hoses have been returned to the proper location and you don't hear hissing (ie. leak).

 

did you recalabrate your idle speed yet. If not look in the how to section they have a full write up on how to properly reset your idle.

 

The write-up on cleaning the iacv didn't say anything about resetting idle. Why? I'll see what happens thanks guys.

Is this what i gotta do to adjust base idle?

How to adjust IACV -

Warm the engine up to operating temp.
Turn off the engine.
Disconnect the TPS.
Start the engine and adjust the idle speed using the stop screw on the throttle body to 650 RPM's.
Turn off the engine.
Reconnect the TPS and restart the engine.

If the IACV is working correctly your idle should be correct. If it's a bit low, try adjusting the screw on the IACV bypass to get your idle speed to ~700 in neutral with no load. (no load means no lights or A/C)

 

Yes, that is what you need to do to adjust base Idle. I don't know if it will do anything b/c I didn't have to adjust my idle after cleaning, but its worth a try.

 

Well there is a hissing sound right where the iacv is. What could be some possible problems?

 

Vacuum leak. That's what's causing your car to run rough. Did you reinstall the IACV gasket?

 

You might need to change your IACV gasket. Definetely check hoses for cracks. Its going to be a Pain to find it. Did you tighten the screws to the appropriate torque.

 

When i start the engine when cold, the rpm goes to 1400, then fairly quickly goes down. then the engine starts to sputter. then RPMs jump up and down. It seems as though the ecu is confused about what speed to idle at.

Oh ye and I started the engine by mistake to back the car up when the iacv was off. it started and shut down immediately by itself. You think this had something to do with it?

I'm pretty sure i tightened it pretty good but i'll check. but wow, a thin gasket like that can cause something like this!!??

 

BTW, does anyone know what the torque specs are for the iacv?

 

Don't bother with the torque specs, but if you must know it's 13-17 lb-ft. BTW, i suggest that you reset your ECU.

 

thanx
10 char

 

quick question. I'm gonna take apart the iacv and re-install it. It seems like an adhesive was holding the gasket in place. Is there a special kind of adhesive for that? What is it called?

 

You don't need to use adhesive. Just scrape off all that stuff (carefully) from the mating surfaces and replace the gasket with a new one. Make sure you look at the orientation of the old gasket.

 

Sorry very newbie question here. If you're tightening by hand how 'exactly' do you torque to spec? They give torque specs in terms of force (e.g. 22-29 ft-lbs for the oil drain plug) but how can you tell you're applying the right amount of torque without some precise machine-o'meter.