Mechanics

MAJOR ACCELERATION/BRAKE ISSUE

2004 Honda Accord • 173,000 miles

At around 160,000 miles, I had made a turn onto a residential street and proceeded around 25 mph. Suddenly, the throttle was pulled wide open and my car took off on me. I reached speeds of around 80 mph and the brake pedal was not functioning. Luckily there was no cars in front of me or I wouldnt be here right now. I brought it to my mechanic and he said that the cruise control cable wrapped around the throttle and got stuck. The mechanic removed the entire cruise control system and the problem seemed to be fixed. Until last night. Around 173,000 miles, I was getting off of a major highway in new jersey and turning onto a residential street again, only this time there were cars in front of me. My car again took off and I had to get on the shoulder and fly past the traffic before I could react. Please tell me what is happening and if its worth fixing or just getting rid of it. I would rather not die over a small problem
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David_bardes
August 18, 2013.




Ask your mechanic if your car uses the extremely dangerous "throttle by wire" system that put Toyota in the news a couple of years ago. I personally will never own a car that replaces a common sense pedal and cable with an insanely complicated computer, two position sensors and a motor to run the throttle blade.

My guess is your car doesn't have that because the cruise control is built into the computer and is not run with a servo and second throttle cable. I would look at the cable guide to see if it is bent or the cable is mispositioned allowing it to ride up on the side of the guide when you release the pedal. Also be sure the throttle blade is releasing freely when you work it by hand. When it does it will take up the slack in the cable as it is released. If the throttle blade is binding due to carbon buildup, a releasing cable could pop off the side of the guide. That would prevent it from going to idle. Chances are if that happened you could get it to reseat in the guide by pressing the pedal to the floor and releasing it.

If this happens again, just turn off the ignition switch, then, if possible, stop as quickly as possible without bouncing through any more pot holes than necessary to avoid jarring anything, then inspect the throttle cable and guide to see if what caused the high engine speed is still present. If the cable has walked up on the side of the quarter-round guide, that is what needs to be addressed. If the throttle is sticking open and the cable is slack, a good carbon cleaning is what is needed.

The apparent loss of brakes is only due to the loss of power assist when engine vacuum is lost. That happens to all cars with the normal vacuum-operated power brakes. The loss of assist occurs at wide-open-throttle and when under heavy load or hard acceleration. Engine vacuum goes way down during those times. You will not lose your brakes, just the power assist. You have to push harder than normal to stop the car but if you try to slow down gradually, as in a half mile or more, you are likely to overheat the brake linings resulting in one form of brake fade. That renders them ineffective so you have to push the pedal harder. That overheats them more and aggravates the problem until it seems like the brakes don't respond at all. Just stop the car as quickly as possible before the linings have a chance to get real hot.

Caradiodoc
Aug 18, 2013.


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