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Throttle applied when braking

Old Sep 16, 2010 | 06:09 PM
  #1  
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Default Throttle applied when braking

Now here's a weird problem I haven't full diagnosed yet. Let's see join me in analyzing the problem

Symptom: when I brake, throttle is applied.

Facts:
  • It's not vacuum related because it's the actual throttle cable that is being tightened.
  • I replaced the throttle cable without any change.
  • There's no interferance or sound proofing or anything under the pedals
  • Throttle is not affected when braking when the car is still or when reversing. It's only applied when stopping the car when rolling. Super easy on the brake, not so much throttle. Heavy braking, about 20% throttle.
  • I can force the throttle pedal back to 0% position but the tension is still in the wire. To fully remove the tension I have to apply full throttle.
  • The throttle wire/cable runs without interferance from the firewall to the engine.

I haven't had time to investigate more. Perhaps a cracked firewall? But it's strange that it only happens when stopping the car from rolling forward. There's nothing loose around the throttle cable in the engine compartment. But it seems that something is flexing that pushes the cable which in turn tensions the wire. Weird little problem
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Old Sep 16, 2010 | 06:42 PM
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Originally Posted by Duke
Now here's a weird problem I haven't full diagnosed yet. Let's see join me in analyzing the problem

Symptom: when I brake, throttle is applied.

Facts:
  • It's not vacuum related because it's the actual throttle cable that is being tightened.
  • I replaced the throttle cable without any change.
  • There's no interferance or sound proofing or anything under the pedals
  • Throttle is not affected when braking when the car is still or when reversing. It's only applied when stopping the car when rolling. Super easy on the brake, not so much throttle. Heavy braking, about 20% throttle.
  • I can force the throttle pedal back to 0% position but the tension is still in the wire. To fully remove the tension I have to apply full throttle.
  • The throttle wire/cable runs without interferance from the firewall to the engine.

I haven't had time to investigate more. Perhaps a cracked firewall? But it's strange that it only happens when stopping the car from rolling forward. There's nothing loose around the throttle cable in the engine compartment. But it seems that something is flexing that pushes the cable which in turn tensions the wire. Weird little problem
Motor mounts....the car stops when brake is applied but the motor keeps going.....stretches cable.....opens throttle...

Check your tranny mount too.
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Old Sep 16, 2010 | 06:49 PM
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First Dart... Motor mounts. Second Dart...Residual Speed Demon symdrome. Sounds like a good excuse to ask you for more engine pics.
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Old Sep 16, 2010 | 07:19 PM
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if it's not motor mounts, clearly you need to have liposuction of the feet Mr. Canoes for shoes.
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Old Sep 16, 2010 | 10:01 PM
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Duke, wake up!!! We want to know if it's the motor mounts....

http://www.worldtimeserver.com/current_time_in_SE.aspx
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Old Sep 17, 2010 | 08:35 AM
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You've absolutely ruled out floor mats and/or carpet?
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Old Sep 17, 2010 | 08:51 AM
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Or the right foot that always wants to be on the accelerator pedal.
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Old Sep 17, 2010 | 11:55 AM
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Its your cruise control still connected? I cant remember from your pictures. If it is, perhaps its cracking out.
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Old Sep 17, 2010 | 12:06 PM
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Ya I would start by disconnecting or removing anything else that could be connected to the throttle. Floormats, cruise control, etc.
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Old Sep 17, 2010 | 02:08 PM
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left foot brake
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Old Sep 17, 2010 | 03:06 PM
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The suggestion that it is the motor mounts is interesting, but that would also translate into the same amount of forward motion of the transaxle, since the two are connected.
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Old Sep 17, 2010 | 03:28 PM
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Maybe Duke is hitting the brakes SOOOOOO hard, the gas pedal is pushing down under its own, now massive, weight...
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Old Sep 17, 2010 | 03:46 PM
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Originally Posted by JohnKoaWood
Maybe Duke is hitting the brakes SOOOOOO hard, the gas pedal is pushing down under its own, now massive, weight...
This could be it.... He needs to check if the part# on the gas peddle starts with 928-If so, he's gonna need a bigger return spring on the throttle body....a lot bigger.




Sorry, I'll go now.
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Old Sep 17, 2010 | 04:47 PM
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Originally Posted by Lemming
The suggestion that it is the motor mounts is interesting, but that would also translate into the same amount of forward motion of the transaxle, since the two are connected.
Nothing he says rules that out though. It would be easy to tell though...

Duke, does the shifter move forwards when this happens?
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Old Sep 17, 2010 | 08:33 PM
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your girlfriend has secretly fitted a block of hard wood to the underside of the accelerator pedal in fear of your life and it is the mass of this block thats causing the trouble
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