Serious hanging idle problem...please help.

[Rick Lee]

Marcesq and I got my car buttoned up and running tonight. A full G50 clutch R&R and a bunch of little little stuff later the car revs very high as soon as I'm moving. Letting the clutch out in first, the car runs without my pressing the accelerator. While shifting the idle does not go down nearly as far as it should when I pull off the gas and depress the clutch. On the 30 min. drive home tonight it just got worse. I used to be able to kill the problem with a quick throttle blip in neutral. Now it just stays real high. What is going on and how do I fix it? After all the work we just did, it's really a buzzkill to have this problem now. I feel like it's dangerous just driving around a parking lot, looking for a parking space. PLEASE ADVISE. Thanks.

[Jess]

I'm going to assume that your installed the two throttle return springs correctly, (one down below the intake runner at the bell crank on the engine shroud and one up near the throttle body).

I bet that you routed the clutch cable incorrectly and it is rubbing on the bell crank on the driver's side of the transmission. I can't remember for sure, but I think the cable is supposed to go under the bell crank. As I remember (made the same mistake myself) it's kind of counter-intuitive.

Take a look at yours. If the cable is rubbing on that bell crank, it's routed wrong, just undo your clutch cable at the clutch arm and do route it the opposite way.

It causes the throttle to hang up like you are describing.

Let us know,

Jess

[Doug E]

Richard - WTH? After all that work don't let something like this get you down. Don't worry, the board will save you!

FWIW, I don't remember how we routed any of the cables so I'd take a good look at everything just to make sure it's correct.

[Rick Lee]

My car has a G50 clutch and tranny, which is a hydraulic system - no clutch cables. And this problem existed before the clutch R&R, but seems worse now.

The cable which comes out of the cruise control housing seems to stick a little. When I keep the car idling and run back to poke around the engine, it seems that cable is the problem. I'm starting to think it's getting hung up in the crusie control housing somehow.

Does anyone know if any part of the throttle system needs greasing, what kind of grease and at what intervals? Thanks.

[mhackney]

Richard, my "new" 70 911 S (MFI) started doing a similar thing this weekend. I've only had the car for 4 weeks so I am getting used to it but it seems pretty well sorted. Anyway, the throttle would stick and I know what you mean about it being scarey!

My problem was the throttle cross shaft that spans the 2 throttle boddies. The ends of this shaft rotate in a mating hole in the throttle bodie and these were binding. I removed all of the throttle linkages connected to the shaft and verified that it was not rotating freely. I squirted WD40 on the shaft ends and used rags to slowly clean out the accumulated grease, etc. Once things were moving freely I gave a quick blast of compressed air and then lubricated with a wee bit of lithium grease. While I was there I removed, cleaned and greased all of the ball joints on all of the linkages. Major improvement! I didn't have to take the cross shaft out to do this - I think that requirse removing at least 1 throttle body. I'll do a more thorough job on some future project when I have the bodies off.

[ChrisBennet]

For now, pulling up on the gas pedal with your toe should bring the idle back down.

There should be a little slack in the throttle linkage when you aren't pressing on the gas pedal i.e. no tension on the throttle rod going from the transmission to the motor. Readjust or straighten it if you bent it.

Floor mats can get pushed onto the gas pedal.

Cruise control wire/cable goes through a bracket on the engine. The bracket accepts the square plastic end of the cable sheath. This part tends to break allowing the cable wander closer to the throttle return spring. (I've had this cause a stuck throttle once.) If it is loose in the bracket, zip tie it in place.

-Chris

[Thomas Owen]

Richard, don't panic. Take a look at the picture below. When I reassembled my engine I tightened this clamp in the wrong position. When I pressed on the accelerator it would lightly hang against the clamp. If it is not this, it almost has to be a spring or a linkage misrouted or misaligned.




Good luck - let me know if you need any other pictures.
Regards,

[Rick Lee]

Thanks guys. I'm gonna have to deal with this on Saturday, when I can actually see what I'm doing. I tried pulling into a well-lit gas station last night and still couldn't get a great view under the decklid. I'll have my girlfriend sit in the car and hit the gas pedal while I observe what's moving around and where. Other than that, the car just so kicks a$$ now.