Throttle sticking open when changing gear

[frankyknuckles]

During my fisrt two sessions at Donnington yesterday I had a problem with the throttle.

When on full throttle and max revs (it did not do this at part revs only full) and then changing gear, when I released the throttle and dperessed the clutch, the revs would bounce on the limiter and the needle appeared to bounce between no reves and the red line.

When I retunred to the pits, I removed the pedal box cover and operated the throttle with my hand, it did not stick. I looked at where is connects to the throttle bodies and it all seemed fine. Albeit, when I relaesed the pedal from fully depressed, the thing that the cable is attached to on the throttle bodies would spring back with a loud click where it hit the stop, but then would bounce very slightly, certainly not enough to cause full revs.

I then checked the route of the throttle cable, it was fine, but I did play around with the loom and found an even cleaner route for the cable.

 

I went back out and had the same problem.

Then, on my 3rd session and there after, it did not happen again and the car seemed fine. There was another R300 on track with me and we were very very evenly matched, so it has not affected performance (I also kept up with a few porker GT2's ).

 

I have not used the car on track for a few months, so I'm wondering if anything might have got a little stiff with no use ???

 

Any ideas at what I should be looking at ?

 

www.R300.net

[Strangely]

I had similar symptoms (throttle stuck open approaching a bend on a country road 😳). The problem turned out to be at the pedal end. There's a big hole in the top of the pedal. Inside it fits a bush, and a bolt goes through that into the chassis. There wasn't much of the bush left on mine, so rather than pivoting freely, it was sticking. Of course, my lead feet were enough to overcome the resistance when pressing on, but when I came off the pedal, it was sticky enough to keep the throttle open.

 

It took about 85k miles to get into that state, so I don't know how likely it is to be your problem. Easy to check though.