Gas pedal sticking @ the top
09-10-2016, 07:37 PM
#1
Gas pedal sticking @ the top I did a search but nothing gave me that ah ha moment so I am asking for help.
My gas pedal has an intermittent stiff spot at the first 1/16"-1/8" of the pedal. It seems more pronounced once the car is warm and on the highway, after I release and go to step back on the gas.
My mechanically inclined friend removed the throttle cable from the t/c unit, the cable and the butterfly on the t/b move freely. How do I know if the problem is the t/c or cruise control unit itself or is it an electronic problem from the plug that goes into the t/c unit? Unlike most I would like to keep the cruise and the t/c. I am sure I can find a good used unit but I would like to try not to guess wrong b/c the parts will be non returnable. Thanks for any help, sorry of it is a lot of wind lol.
My gas pedal has an intermittent stiff spot at the first 1/16"-1/8" of the pedal. It seems more pronounced once the car is warm and on the highway, after I release and go to step back on the gas.
My mechanically inclined friend removed the throttle cable from the t/c unit, the cable and the butterfly on the t/b move freely. How do I know if the problem is the t/c or cruise control unit itself or is it an electronic problem from the plug that goes into the t/c unit? Unlike most I would like to keep the cruise and the t/c. I am sure I can find a good used unit but I would like to try not to guess wrong b/c the parts will be non returnable. Thanks for any help, sorry of it is a lot of wind lol.
09-11-2016, 10:05 AM
#2
The traction control on our cars is primative and isn't what you want it to be. It doesn't operate the throttle, just the brakes - so that other cable is just for the cruise control only.
So, you've disconnected that cruise control unit and the problem goes away?
So, you've disconnected that cruise control unit and the problem goes away?
09-11-2016, 03:34 PM
#3
Thank you for taking the time to reply Wssix99. After driving the car today I now know we unplugged the traction control unit not the cruise and it felt much better. I reconnected it after a bunch of miles and it is still better. Maybe there was a glitch somewhere?
09-12-2016, 06:23 AM
#6
In what sense are you explaining this? The T/C servo does operate the throttle in low traction situations. It will feel as though the gas pedal is pushing back against your foot, almost like ABS feels on the brake. But under normal driving, it simply translates both the throttle and cruise linkage straight into the single cable going to the TB. I'm sure you already know that, just don't want OP to think that servo does nothing at all.
09-13-2016, 11:28 AM
#7
I am not a TCS expert on these cars and was basing my information on where the "brain" is. I was not aware the system crossed over to the cruise control bits & pieces. I assume that the TCS option would have required cruise control, then?
^ Then this would make sense of everything above. Spartain7 - can you help us decipher the rest of this? If TCS is activating the servo at the wrong times, I'd expect there are other safety issues that could be going on with the car - perhaps something that could cause issues with the ABS system down the road.
I'm wondering now if there might be any error codes stored in the ABS/TCS system indicating an odd condition with a sensor?
The T/C servo does operate the throttle in low traction situations. It will feel as though the gas pedal is pushing back against your foot, almost like ABS feels on the brake. But under normal driving, it simply translates both the throttle and cruise linkage straight into the single cable going to the TB.
I'm wondering now if there might be any error codes stored in the ABS/TCS system indicating an odd condition with a sensor?
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09-13-2016, 11:58 AM
#9
As I understand it, there are 3 elements to TCS/ASR; individual brake modulation of the rear wheels via ABS (on LT1 cars this was done by a separate module), then control of the throttle/cruise cables by the servo motor mounted on the front of the passenger wheel well (on LT1 cars, it's mounted above the driver side valve cover), and finally by the PCM cutting fuel.
If the servo is controlling the cable at the wrong time, it should be a simple matter of unplugging it and seeing if the problem goes away. Then the cam on the servo becomes a simple linkage connection to the TB. The "brains" of it all is the EBTCM, the cable servo is just a motor.
It sounds like OP did this and the issue improved. OP, if the issue comes back, I'd unplug it again and see if that improves it. If so, it might be a bad servo motor, or the EBTCM is commanding it at the wrong time, the latter of which is over my head.
If the servo is controlling the cable at the wrong time, it should be a simple matter of unplugging it and seeing if the problem goes away. Then the cam on the servo becomes a simple linkage connection to the TB. The "brains" of it all is the EBTCM, the cable servo is just a motor.
It sounds like OP did this and the issue improved. OP, if the issue comes back, I'd unplug it again and see if that improves it. If so, it might be a bad servo motor, or the EBTCM is commanding it at the wrong time, the latter of which is over my head.
09-13-2016, 10:35 PM
#11
Maybe it's the most simple thing after all? After having another couple of Ls friends look at my car the cruise control motor does have a little sticking when turning it by hand. My buddy drove the car and definitely felt what I feel and said it's not normal. Does that adjuster peace in the center of the cable work by vacuum to stiffen the throttle? Maybe it is too tight?
09-15-2016, 07:05 PM
#14
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Probably a stupid question, but have you checked the throttle body blade to make sure it isn't gummed up with carbon deposits or adjusted incorrectly?
When I changed to a ported throttle body, I had to adjust the idle screw to get the blade to stop sticking slightly at idle.
When I changed to a ported throttle body, I had to adjust the idle screw to get the blade to stop sticking slightly at idle.