engine won't idle

[pszikla]

Hi Everyone!

Have a `99 996 C2

Car was running just fine and last time it was started, idled well until the first stop sign and as i clutched to neutral the engine stalled. Starts up again right away but unless I hold the gas pedal to maintain about 1500rpm, it will stall.

Limped it over to my Indy, and he read the fault code that indicates defective MAF.

Installed a new one but didn`t change a thing.

Any ideas...

thanks

Pete

[Loren]

:welcome:

The MAF is not even used during idle. You can disconnect it and it will not affect the idle. The MAF comes into play at higher RPMs.

Chances are your Idle Control Valve is stuck closed or the solenoid has failed.

Do a search here and tip on cleaning the valve and testing it.

[pszikla]

The MAF is not even used during idle. You can disconnect it and it will not affect the idle. The MAF comes into play at higher RPMs.

Chances are your Idle Control Valve is stuck closed or the solenoid has failed.

Do a search here and tip on cleaning the valve and testing it.

Thank you Loren, I'll check those 2 items.

P.s. I forgot to list the fault codes which were: P0102, P1123, P0154, P1602

[Loren]

I would clear those codes and see which (if any) come back after you fix your idle control valve.

[Robert Wright]

Hi Everyone!

Have a `99 996 C2

Car was running just fine and last time it was started, idled well until the first stop sign and as i clutched to neutral the engine stalled. Starts up again right away but unless I hold the gas pedal to maintain about 1500rpm, it will stall.

Limped it over to my Indy, and he read the fault code that indicates defective MAF.

Installed a new one but didn`t change a thing.

Any ideas...

thanks

Pete

[Robert Wright]

Had the identical problem with my 99' 996 as would not idle but ran like a "champ" at higher RPM's. Let up off the throttle and the engine would fall off and stall. Replaced the idle control valve and held my breath when first started up and idled perfectly and has run great since. Took a couple of weeks but Sunset did provide a replacement ICV at a competitive price.

[pszikla]

Had the identical problem with my 99' 996 as would not idle but ran like a "champ" at higher RPM's. Let up off the throttle and the engine would fall off and stall. Replaced the idle control valve and held my breath when first started up and idled perfectly and has run great since. Took a couple of weeks but Sunset did provide a replacement ICV at a competitive price.

Hi Robert!

did you have the same fault codes as me?

I haven't had the time to work on her yet but I am feeling a little better that it may not be the computer that i have to change!

Peter

[Robert Wright]

Peter,

Interestingly enough, when I was having my ICV related problems I was not logging ANY fault codes at all.

[pszikla]

I would clear those codes and see which (if any) come back after you fix your idle control valve.

Hi Loren!

I have removed the idle control valve, liberally sprayed carb cleaner into both orifices and gently moved the flap from closed to open.

I'd like to test it electrically but it has 3 pins identified 1, 2 and 3 and I don't know which is positive and which is negative and I don't want to take a chance and burn out with wrong polarity.

Do you happen to know which is which by any chance.....if not...no worries, I'll take it over to my Indy and ask him.

thank in advance,

Peter

[Loren]

pin 2 is power

pin 1 closes the valve

pin 3 opens the valve

I think it goes in steps so it may only move a small amount each time you ground pin 1or 3.

Check continuity first - most bad valves are open.

[pszikla]

pin 2 is power

pin 1 closes the valve

pin 3 opens the valve

I think it goes in steps so it may only move a small amount each time you ground pin 1or 3.

Check continuity first - most bad valves are open.

Thank you Loren, I'll give it a try.

Pete

[pszikla]

pin 2 is power

pin 1 closes the valve

pin 3 opens the valve

I think it goes in steps so it may only move a small amount each time you ground pin 1or 3.

Check continuity first - most bad valves are open.

Thank you Loren, I'll give it a try.

Pete

Loren!!

thank you, thankyou, thank you!!!!!

Thoroughly cleaned the ICV valve, tested it and the selenoid functionned the rotating gate which had been stuck closed when i removed it.

Reassembled everything, fired her up and she idles like a champ!!

I am so happy and i am very gratefull for such a wonderful site and someone as knowledgeable and helpful as you!

I shudder to think had i left it at the Indy's, he wanted to change the computer next...he had already billed me for a MAF sensor that

you pointed out doesn't even work at idle. I'll keep the MAF installed because i presume that at 71000 miles it may be due for a change.

thanks again!

Pete

[nghiaho58]

I had the same (not idling) problem on my two Lexus cars when they had about 100K miles. I fixed the problem by cleaned out the ICV. I think the problem was cause by using a cheap gas (Costco & Arco). Since then I started to use Mobil or Shell gas and haven't had idling problem, both cars have about 150K miles now.

Would you post instruction/pictures of how to clean/replace the ICV?

Thanks.

Nghia

[eggodynamics]

I had the same (not idling) problem on my two Lexus cars when they had about 100K miles. I fixed the problem by cleaned out the ICV. I think the problem was cause by using a cheap gas (Costco & Arco). Since then I started to use Mobil or Shell gas and haven't had idling problem, both cars have about 150K miles now.

Would you post instruction/pictures of how to clean/replace the ICV?

Thanks.

Nghia

One should clean the throttle body butterfly and intake tube with throttle body cleaner spray and a lint free cloth every 25k miles. You can easily push it open and prop it with a screwdriver handle for easy inspection/cleaning.

Use a good quality fuel injector cleaner as well in the tank every few months. Pump gas is dirty, and the air in the good old USA isn't

exactly pristine either.

Edited April 21, 2010 by eggodynamics

[pszikla]

I had the same (not idling) problem on my two Lexus cars when they had about 100K miles. I fixed the problem by cleaned out the ICV. I think the problem was cause by using a cheap gas (Costco & Arco). Since then I started to use Mobil or Shell gas and haven't had idling problem, both cars have about 150K miles now.

Would you post instruction/pictures of how to clean/replace the ICV?

Thanks.

Nghia

Hi !

Assuming you have a '99 engine because from 2000 on the ICV valve is replaced by electronic throttle control.....just do a search using ICV, rough idle, won't idle etc...... Doing that, I found someone that had posted with photos on doing this simple procedure on a Boxster engine and really it is simple.

good luck!

Peter