CIS Throttle Linkage Adjustment

[echrisconnor]

I was looking over the car yesterday and noticed that my throttle linkage is out of adjustment. I tried to do some adjusting but wasn't able to get it fully sorted out.

The problem is that when you floor the car, the throttle doesn't open all the way. If I shorten the arm that goes from the pivot to the throttle valve, then I can get full throttle with the pedal, but it won't drop down to the minimum setting. With my adjustment it has the proper minimum setting, and if I step on the pedal very hard, flexing the floorboard, it goes to about 1 mm before the full open stop.

Is there a procedure for adjusting this? I also noticed that the pivot is worn and that little assembly with the two arms and ball joints on it moves around a fair amount.

[Gunter]

I found the same thing and played with all the adjustments from throttle to pedal and could not get the complete range between idle and full throttle. Other people had this problem. There seems to be very little room for a satisfactory adjustment. I am thinking about making a small cut-out in the front carpet to get the pedal down a little more.

[echrisconnor]

The carpet cut-out is what I ended up doing. Doesn't seem like the best way to approach it. Do you know if you can replace bushings in the pivot which connects the two linkags? It had a fair amount of slop in it which could account for the non-adjustability.

[fred cook]

On my '80 SC coupe, there are three places to adjust the throttle. At the pedal, under the car and inside the engine compartment. A few months ago, I replaced the driver side pedal board and wound up with less than full throttle. By working all three of the adjustment points, I was finally able to get full throttle travel. Caution, once you have finished making adjustments, have a helper press the gas pedal to the floor and double check to make sure you will not have any linkage lockup!

Good Luck!

Fred Cook

[echrisconnor]

I didn't see the adjustment under the car. It seems I can get the full range of motion for the cable in the engine compartment. It just won't translate to full throw on the other linkage.

Does anyone know part numbers for the bushing #32 in this diagram?


Also, it looks backwards on my car (from my memory). The pivot arm 33 is connected to the throttle cable coming out of the firewall. Arm 35 is the one which connects to 38 and then up to the main throttle valve #6.

When adjusting, is it important that 33 is 90 deg. vertical when the pedal is at rest, or should there be some angle set there to begin with.

[81 930]

Looks like the P/N for the bushing is 901 423 253 00.

I'm in the process of changing my intercooler and was planning to check my throttle linkage at WOT at the same time. Good post. Let us know what you find.

Regards,

Brian

[juanbenae]

get two of the bushings they both will need a replacing. a ppi on my car pointed it out as a "bell crank bushing" if i recall. another wrench set me up with a couple by that name.

[echrisconnor]

Has anyone ever replaced these bushings? Do you know if it can be done with the assembly in the car, or do I need to pull the whole thing out?

[juanbenae]

i did mine and you need to pull a lot of S out of the way 1st then it still a tight fit. when you say assembly do you mean the linkage or the entire CIC unit? just the linkage, remove bolt #35 and the entire stud will pull out to the left. the linkage #38 will be as far as you need to go. it has a little spring loaded clip affair that comes off by slidding it down the linkage shaft. if you dont have a bentley manual i would print the exploded view posted here

[echrisconnor]

I was wondering if you need to pull the plate (31 )out of the car completely, or if I can just pull that bolt (35) and pop the bushings out and in with my hands. Or, if I need to pull the plate (31) and have it taken to a shop to press the bushings out.

[MBAtarga]

Originally posted by k911sc
get two of the bushings they both will need a replacing. a ppi on my car pointed it out as a "bell crank bushing" if i recall. another wrench set me up with a couple by that name.

My PPI had the same item reported. It was itemized as a $320 repair. I imagine the bushings MIGHT be $10 at the dealer. I plan to do this myself, some day.....after you post your findings.

[Gunter]

The two bushings are not that hard to replace. If you don't have too much stuff in the way, like heater blower, etc. They are not a hard "press-fit". Pop off the linkages and try to get at the bolt/nut (35) and slide the rod out. If that is too hard to do, take the whole plate assembly off from the casing and replace the bushings. On mine, there is some more adjustment in the long rod leading from the that plate (31) down through the firewall onto the connection close to the left side of the transmission. I don't like the hole in the carpet either but after playing with the adjustments for hours I might just do that.

[juanbenae]

the part 31 does not come out. remove nut 37 and all of the junk on the 33 lever and it will pull out.

[echrisconnor]

I pulled that whole plate out last night (31). It was pretty easy to remove, since I have my blower and all hoses already out of the way. When I disassembled it, the bushings are totally shot. The were really just crispy pieces of junk. I'm trying to find the part today, and it looks like a really quick fix.

I'll keep you posted.