Sticky Accelerator

Max911SC · 07-04-2003, 11:35 AM

On my 87 Carrera, I have been having a "high" idle problem. I thought it might be the idle control valve, so I took it off and cleaned it. The problem seemed to go away (for a short while)but then returned.

When the car was idleing too high, just by chance I reached down to the pedal and pulled it back with my hand and WA-LA the idle return to normal. (If I kick the pedal it usually will get the same result.)

Is there an easy fix (aka WD40)? Can I do something to the pedal to eliminate the sticking? Or is there something else I should be doing to get to the root of the problem. Thanks.

Jim Sims · 03:09 PM

Look for broken springs (two of them- not shown in the following diagram) on throttle linkage at top left front of engine. Look for the bellcrank on the driver's side of the tranmission being jammed by a clutch cable (any tranny or engine work lately?). Look for worn or dirty plastic bushings on pedal (18) or bell cranks (13) (the one on the transmission and the one on the top of the engine- not shown in the following diagram) or worn linkage rod ends (6). There are also three plastic bushings(11) in the tunnel that guide the horizontal rod portion of the throttle linkage. Numbers refer to the parts in the diagram of the next post. Do not use WD-40; it is a perservative and not a good lubricant. It will dry to a sticky, gummy condition - not desirable for a throttle linkage. Pelican sells most of the linkage repair parts one might need. Jim

Jim Sims · 07-04-2003, 03:05 PM

Sonic dB · Sonic dB's Garage

Just a thought, check your cruise control cable, where it attaches to the throttle in the engine. There is a clip there. If it is broken, the cable can get stuck open. This happened to me, cars throttle would just get stuck wide open...and I just put some twisty ties on it to make sure that it doesnt come loose and it solved the problem.

Max911SC · 07-04-2003, 08:07 PM

Thanks for the diagram. No engine or tranny work done lately and I don't think it's the cruise because the cable is not hooked up to the throttle. Are there any good lubricants that may help the "sticking"?

rickeolis · 07-04-2003, 10:31 PM

I had to rebuild my pedal cluster last year because the bushing (#18) had dissolved, leaving the lever joint (#17) to have side play to the point where it caught onto some sheet metal near the assy.
Check for sideplay there, this could cause your problem too.

Jim Sims · 07-04-2003, 10:36 PM

One can use a light grease in the rod ends; the plastic bushings are usually left unlubricated (oil and grease just collects dirt) but if you feel the linkage needs something then use an aerosol silcone spray lubricant and wipe up any excess. I'm predicting you have a missing or broken spring or a worn plastic bushing somewhere. Jim

Max911SC · 07-07-2003, 04:28 AM

How hard is it to rebuild the pedal cluster for an avg. DIY?

Jim Sims · 07-07-2003, 07:19 AM

Most difficult task (and for some it was very difficult) is driving out the spirol roll pin; one often needs a good vise to hold the assembly while driving out the pin. Some have had to resort to drilling it out or the use of a shop press to push it out. Be sure and replace it with the correct OEM replacement spirol pin. A regular "C " section roll pin will not have adeqaute section/shear strength for the loads the pedal cluster experiences. Also be sure you have all the required bushings and spacers (plastic or brass) for the brake, clutch and throttle shafts; off the top of my head there are 7 bushings (including the small one in the end of the tube piece ear for the clutch cable clevis) and one plastic spacer. If the bushings have been allowed to wear through one may find a cracked tube piece and grooves worn in the other shafts. Cheers, Jim

jhugh · 07-07-2003, 07:39 AM

I have this same exact problem on my '84.

I rebuilt the pedal cluster and installed the new bronze bushings. That wasn't it. What it is on mine is that the arm on the cluster to which the gas pedal rod attaches (#17 in the above diagram), is getting metal fatigue and bends to the right. Especially if I stomp the gas hard! When it's bent over to the right far enough, it rubs against the clutch linkage, and starts hanging up.

When it bends over like that, I just pull over, reach down and bend it in a little, keep driving. But someday I'm gonna have to replace that piece.

good luck

cmonref · 07-07-2003, 11:33 AM

jhugh,

Whem you "stomp the gas", is the throttle linkage hitting mechanical stops somewhere along the line BEFORE the gas pedal hits ITS mechanical stop on the floorboard. The only way that #17 could be bent would be for the linkage to have been fixed in position ((by something ELSE hitting ITS mechanical stop) before the gas pedal does.

The gas pedal should hit its stop just as the throttle reaches fully open. If you achieve that relationship, and all of the intermediate pieces are also operation BETWEEN their stops, you should not be able to put enough force on good ole #17 to bend it.