need HELP with stuck throttle
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Several things:
1. Examine the actual Throttle Blade and see if its open 100% at Full throttle.
2. Do the foot on the throttle when cold and examine the throttle blade and see if its actually changing that % you are seeing on the scanner.
3. Examine the throttle blade and see if it responds SMOOTHLY to someone pressing the accelerator Peddle smoothly to full open.
4. At the rear of the drivers fuel ril is a black medal bracket. On some C5s the wiring harness on the top drivers side of the car pulls TIGHT against that bracket and can damage the wiring. (Guess what wires goes through that harness??)
SO,, Examine that harness where it bends around that bracket and see if that could be part of the issue.
That bracket is actually a fuel rail stop to prevent the fuel rail from shifting rearward in an accident and sheering off.
1. Examine the actual Throttle Blade and see if its open 100% at Full throttle.
2. Do the foot on the throttle when cold and examine the throttle blade and see if its actually changing that % you are seeing on the scanner.
3. Examine the throttle blade and see if it responds SMOOTHLY to someone pressing the accelerator Peddle smoothly to full open.
4. At the rear of the drivers fuel ril is a black medal bracket. On some C5s the wiring harness on the top drivers side of the car pulls TIGHT against that bracket and can damage the wiring. (Guess what wires goes through that harness??)
SO,, Examine that harness where it bends around that bracket and see if that could be part of the issue.
That bracket is actually a fuel rail stop to prevent the fuel rail from shifting rearward in an accident and sheering off.
Instructor
Joined: Sep 2006
Posts: 153
Likes: 4
From: Santa Maria Ca
Thanks Bill, I had that exact issue on my old C5, throttle body wire rubbed through on the bracket you point out, and would occasionally blow the fuse.
But this issue is on our C6's. Are you saying the wiring is routed similarly on the C5 & C6? I'll have to take a look.
Anyway, to update this, I installed the new accelerator pedal assembly and still have the fluctuating signals until the car is fully warmed up.
However, I haven't had the sticking throttle issue again. Hard to say at this point whether the accelerator pedal assembly even had anything to do with the original problem.
But this issue is on our C6's. Are you saying the wiring is routed similarly on the C5 & C6? I'll have to take a look.
Anyway, to update this, I installed the new accelerator pedal assembly and still have the fluctuating signals until the car is fully warmed up.
However, I haven't had the sticking throttle issue again. Hard to say at this point whether the accelerator pedal assembly even had anything to do with the original problem.
Racer
Joined: May 2010
Posts: 277
Likes: 4
From: MO
Correct. 88 represents degrees open. When the throttle plate is 100% open its at 90 degrees. So 88 degrees is basically WOT.
Once the pedal is depressed 90% of the way the pcm sends WOT signal so there is really no difference between having the pedal depressed 90%,95%,100%... Its the same output at 90 and above (unless tuned otherwise).
Whats interesting OP is that you dont get reduced power which means that the entire system is seeing consistent inputs/outputs.
By the way I saw that you mentioned opening the door would help reset the system and I can confirm that. When I was facing TB reduced power problems I would have to stop the car, fully turn it off and open/close the door. Simply turning the car off and back on wouldnt reset the REP. Something about opening the door signals to cut the connection.
Once the pedal is depressed 90% of the way the pcm sends WOT signal so there is really no difference between having the pedal depressed 90%,95%,100%... Its the same output at 90 and above (unless tuned otherwise).
Whats interesting OP is that you dont get reduced power which means that the entire system is seeing consistent inputs/outputs.
By the way I saw that you mentioned opening the door would help reset the system and I can confirm that. When I was facing TB reduced power problems I would have to stop the car, fully turn it off and open/close the door. Simply turning the car off and back on wouldnt reset the REP. Something about opening the door signals to cut the connection.
Last edited by Spoolin8; Apr 22, 2016 at 03:45 PM.
