Idle Speed TOO High

[grs7]

2001 GA with 2.4 The idle speed after coming down from high speed idle is about 1200rpm. Oxygen Sensor and TPS sensor have both been changed. Car runs great and very smooth. The IAC seems to bring the idle speed down, but not far enough. Any ideas?

[xeroinfinity]

grs7, is the throttle sticking, lik the linkage or the butteryfly in the TB its self?
May try and lube up the throtle cable and see what you get.
Also wouldnt hurt to take a look in the TB, carbon builds up on the back of the butterfly and it'll stick open if it gets to thick of a build up.
Some good TB/carb cleaner should clean it up nice. I 'wouldnt' run the engine while you clean the majority of the TB though.
It can be cleaned off without removing the TB. An old toothbrush works great for removing carbon in tight places.

other than that causing the fast idle would be a faulty IAC, or you emissions arent working properly.
Their are two O2 sensors, you replace both or just the one down stream?up stream? Weird the TPS needed replaced so soon.... Good Hunting

[grs7]

Originally Posted by xeroinfinity

grs7, is the throttle sticking, lik the linkage or the butteryfly in the TB its self?
May try and lube up the throtle cable and see what you get.
Also wouldnt hurt to take a look in the TB, carbon builds up on the back of the butterfly and it'll stick open if it gets to thick of a build up.
Some good TB/carb cleaner should clean it up nice. I 'wouldnt' run the engine while you clean the majority of the TB though.
It can be cleaned off without removing the TB. An old toothbrush works great for removing carbon in tight places.

other than that causing the fast idle would be a faulty IAC, or you emissions arent working properly.
Their are two O2 sensors, you replace both or just the one down stream?up stream? Weird the TPS needed replaced so soon.... Good Hunting

The throttle does not seem to be sticking. The butterfly and throtle body has been cleaned with throttle body cleaner. It looks pretty clean with no obvious dirty spots. The linkage looks Ok, but I will try to lube and clean it. I relaced the upstream O2 sensor as it was showing a fault. There are currently no faults showing. From my understanding, if the IAC is faulty it would not bring the rpm down at all. It does bring it down from 1500 to 1200.

[xeroinfinity]

Well th e IAC could just be outa tune or carbon'd up.
Did you replace it?
If you did, Sometime you hav to measure the old pental and set the new one at that.
But I would suggest taking it out and cleaning it and the pocket it rests in. DONT turn the tip! It'll get it more outa wack!
Maybe you hav a small vacum leak somewhere, that could cause the idle to stay high and be erratic.

[grs7]

IAC and chamber have bee cleaned up. There was very little deposit build up on it or in the chamber. I have not replaced it yet. I adjusted it as per the Haynes manual to slightly less than 1 and 1/8 inch and it seemed to make it worse. I may have turned the tip when adjusting it.

[xeroinfinity]

you should not ever hav to adjust the old one that was in your car. thats probley why the idles to high. I believe the manual you are refering to says how to adjust the NEW one, set it with the old. But since you hav probley turned it, double check the directions in the manual, then try and adjust it back to where it should be. Good Hunting

[grs7]

I am not sure if it is an IAC problem or not. Here are the idle speeds:
High speed 1500 rpm
Low speed 1200 rpm in park
Low speed 950 in gear.

These speeds are consistant and do not vary any more than 50 rpm. Are these normal rpm's for this car? The low speed rpm's seem to be a little high as comparded to other cars I have had. I have had this car for about a year now and these are the speeds since I have had it. Car runs great and has no power issues. The only reason I am questioning it now, is that in Ontario we have to have cars emission tested ever 2 years. This was the first time I had to have it tested. Some of the emission testing places would not test it with an idle above 1000rpm. I had it tested as is and it is well below the standars set.

[xeroinfinity]

Originally Posted by grs7

I am not sure if it is an IAC problem or not. Here are the idle speeds:
High speed 1500 rpm
Low speed 1200 rpm in park
Low speed 950 in gear.

These speeds are consistant and do not vary any more than 50 rpm. Are these normal rpm's for this car? The low speed rpm's seem to be a little high as comparded to other cars I have had. I have had this car for about a year now and these are the speeds since I have had it. Car runs great and has no power issues. The only reason I am questioning it now, is that in Ontario we have to have cars emission tested ever 2 years. This was the first time I had to have it tested. Some of the emission testing places would not test it with an idle above 1000rpm. I had it tested as is and it is well below the standars set.

THose are High. it should be 850ish @ idle in park. In gear it could drop alittle until you hit the gas. I'd still say the IAC vavles not working, but with out testing it I wouldnt know.
Did you get the O ring in right on the TPS , and the shaft's aligned? the MAP sensor if not working could make the idle high too, it deffinatly emisions related. Check all the vacum lines too, its probley something simple. BUt inthe end to pass your emission tests you just might hav to take it to a shop, OOwwh! I hate that word! Good HUnting

[xeroinfinity]

Originally Posted by grs7

I am not sure if it is an IAC problem or not. Here are the idle speeds:
High speed 1500 rpm
Low speed 1200 rpm in park
Low speed 950 in gear.

These speeds are consistant and do not vary any more than 50 rpm. Are these normal rpm's for this car? The low speed rpm's seem to be a little high as comparded to other cars I have had. I have had this car for about a year now and these are the speeds since I have had it. Car runs great and has no power issues. The only reason I am questioning it now, is that in Ontario we have to have cars emission tested ever 2 years. This was the first time I had to have it tested. Some of the emission testing places would not test it with an idle above 1000rpm. I had it tested as is and it is well below the standars set.

THose are High. it should be 850ish @ idle in park. In gear it could drop alittle until you hit the gas. I'd still say the IAC vavles not working, but with out testing it I wouldnt know.
Did you get the O ring in right on the TPS , and the shaft's aligned? the MAP sensor if not working could make the idle high too, it deffinatly emisions related. Check all the vacum lines too, its probley something simple. BUt inthe end to pass your emission tests you just might hav to take it to a shop, OOwwh! I hate that word! Good HUnting

[corning_d3]

Did you disconnect the battery and let the PCM reset before changing all of those sensors? You really should have..

Also, after changing the IAC motor, did you turn on the key for 5 seconds, off for 10 seconds, then start?

[grs7]

Battery was disconnected and the PCM was set as per the manual. The key procedure was done as well. I will check the alignment of the TPS shaft and check for vacuum leaks . The emmission test was very good, all the levels were well below the accepted standards.
Thanks

Emmissin Test Results

ASM2525 Test @ 2232 RPM Curb Idle Test @ 1200 RPM
HC PPM Limit 60 Result 0 Limit 150 Result 0
CO% .033 0.07 0.70 0.02
NO PPM 450 174 N/A N/A
Dilution 14.9 14.8

Emission Controls sysytems: All Pass EGR System, Air Injection System, Catalatic Converter, Gas Cap Pressure Test,