Idle speed adjustment question

[944pete]

First off, I have an 85.5NA. It has always idled around 1000 to 1100 rpm. I want it to idle 800 to 900rpm. I've taken the adjustment screw competely out and it still will not idle any slower. Even if I physically hold the throttle cam closed as tight as it will go it will not change. Is there any other adjustment? What am I missing?

Pete 85.5NA

[AFJuvat]

Adjust that throttle screw just under the throttle cam. you should hear it click as the throttle cam starts to rotate.

AFJuvat

[Lawrence Coppari]

Assuming the throttle body on an NA is just like a turbo, there are a couple of things you can check. First of all, if you screw the idle screw (brass) in, it slows the idle. If you turn it CCW, the idle speed increases. Secondly, there is a set screw to the right of the throttle body that provides a stop for the throttle. That could be out of adjustment and could be stopping the throttle from fully closing. Lastly, there is a switch to the left of the throttle body. Its purpose is to tell the DME to cut the fuel off when you fully close the throttle or until the RPMs drop to about 1200-1400. If the switch is incorrectly adjusted, it can prevent the throttle butterfly from fully closing. I had my throttle body reamed and when I re-installed the thing, full throttle closure was prevented by my not adjusting the switch correctly. However, the switch will give a little when you turn the throttle to close it. The stop probably will not. The switch should just click when the throttle closes completely.

I found my problem by removing the throttle body and holding it up to the light. I had light around the butterfly indicating it was not fully closing. It works fine now, just like it did before I had it reamed.

Again, what I have said is for a 951. I have been wrong before when I have ventured into the NA world.

[944pete]

The screw I was adjusting was the throttle stop screw. I didn't know there was a screw under the throttle cam. I'll check it out tomorrow. Thanks for the answers.

Pete

[Magnus_944]

http://porsche-944-garage.tripod.com/shop-manual/fuel-08.htm

//Magnus

[arnebret]

Is there a difference between the throttle body from a 951 or an NA?? Adjusting idle is easy, just defeat the idle stabilizer (85.5 on) and turn the screw on the throttle body CW for less rpm and CCW for more rpm. Be sure to warm the car up first...

Just as stated in that document above

[stuttgart]

Hey Pete,
Whats up it's been along time since i heard from ya or seen ya for that matter.. so how is all going with the 944.. why would ya want it to idle lower than 1000? mine does always at 1000.. so does the 911.. well i hope ya sort it all out see around as soon as the weather stays nice.
Eric mckenna
78 911SC
Ohio chapter SCWDP
83 944.. "SOLD" to my sister! hahaha

See ya Pete!!

[stuttgart]

Sorry guys for invading your 944 board... i'll get back over to the 911 side of things!
ciao.

[944pete]

Hey Eric! The 944 is doing great. I'm just hoping to be able to drop a few $$ into it this spring (belts, water pump, tires) I'm also hoping to get a cruise together this spring. ( Yes 911's are welcome) As far as the idle, 1100 is a little too high. I got it down to about 950 and it's a lot smoother on takeoffs now. I gotta make that clutch last.

See ya
Pete