Throttle bore service?

Tiny
MENDYZOEY
  • MEMBER
  • 2013 HONDA CIVIC
  • 98,000 MILES
Hi. I have a serious problem right now. When I remove my foot from the gas pedal, the car continue to accelerate. The gas pedal doesn't get stuck but speed keeps increasing. When I press the brake it only maintains the speed. It does not slow down my car and it does not even stop it. I can only drive at 40km/h and press the brake pedal to maintain that speed. I don't know what else to do.
Friday, March 1st, 2019 AT 4:47 AM

12 Replies

Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Hello and welcome to 2CarPros. Is the service/check engine light on? If so, take the car (carefully) to the nearest chain auto parts store and have them scan it to retrieve the trouble codes. Report the trouble code numbers (not their descriptions, but the actual numbers) here. Then we'll have some insight into what the problem is.

If the service engine light is not staying on, then I'd bet on a sticking throttle actuator or a bad idle air control valve. Either one would definitely cause the engine to run too fast and could do so without the computer setting a trouble code and turning on the service engine light.

I'm including AllData's how-to information on cleaning the throttle body in the images below. Some of it (particularly the last three steps of installation) require some tools that you don't have access to. But here's a YouTube video that will help you circumvent those steps:

https://www.youtube.com/watch?v=YtundPqtKww

and

https://www.2carpros.com/articles/throttle-actuator-service

Check out the diagrams (Below). Please let us know what you find.
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Friday, March 1st, 2019 AT 5:31 AM
Tiny
MENDYZOEY
  • MEMBER
  • 15 POSTS
There is no engine light on.
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Friday, March 1st, 2019 AT 8:31 AM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Have you tried cleaning the throttle body as detailed in my prior post?
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Sunday, March 3rd, 2019 AT 4:05 AM
Tiny
MENDYZOEY
  • MEMBER
  • 15 POSTS
Yes, the gas pedal seems okay, but brakes still not good.
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Sunday, March 3rd, 2019 AT 4:21 AM
Tiny
MENDYZOEY
  • MEMBER
  • 15 POSTS
The speed is decreasing but the brake pedal is useless.
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Sunday, March 3rd, 2019 AT 4:22 AM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
So to be clear, the gas pedal is not operating the way it should. When you let off of the gas, it stops accelerating, right? If so, then we're off to a good start.

Driving the car with the brakes pressed has probably worn out the pads. It might've even overheated the rotors, causing them to warp a little bit. If the car is shaking when you push the brakes, then the rotors have definitely warped. It's probably time to change the brake pads. And if the car shakes when pressing the brakes, then you should also take the rotors and get them resurfaced. I can get you instructions on how to do that if needed.

I'm including AllData's instructions on how to change the brake pads on your car in the attached images. Also, I have some additional tips: (1) Take pictures as you go through the process, so you can reference them if needed. (2) You probably don't have a lift at home, so use a jack and back it up with a jack stand under the frame of the car. (3) If you've not added brake fluid to the master cylinder, do not remove any. If you have added some, don't worry about it just yet, excess will come out on it's own in a later step, just wash it off of the painted surfaces quickly. (4) You can use "brake parts cleaner" that the auto parts stores sell to clean things up. (5) Spray some "white lithium grease" on the caliper pins to keep them lubed. (6) They sell a suitable assembly paste at the parts stores, just use that instead of the "M-77 Assembly paste." (7) A larger c-clamp can be used in place of a brake caliper compressor tool, just put an old brake pad on the caliper piston so the clamp doesn't damage the piston. (8) Be absolutely sure to push the brakes all the way at least 10 times before driving anywhere, or you'll be driving with no brakes at all. Also, you can do this entire job with a basic set of wrenches (metric sizes) and a 6 inch or larger c-clamp without trouble.

Here's our general how-to guide on brakes: https://www.2carpros.com/articles/how-to-replace-front-brake-pads-and-rotors-fwd
I'm also including a link to a youtube video (not one of ours though) on doing the brakes on your car: https://www.youtube.com/watch?v=RktXFq_1XrU

Hopefully this information helps you.
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Monday, March 4th, 2019 AT 4:06 AM
Tiny
MENDYZOEY
  • MEMBER
  • 15 POSTS
I tried what you sent me, but brakes still not working.
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Wednesday, March 20th, 2019 AT 5:29 AM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
When sitting still, engine idling, and you push the brakes, does the brake pedal just go straight to the floor with no resistance? Or does it feel normal?

If the brake pedal goes straight to the floor, then raise the good and check the brake fluid level. The fluid reservoir is located atop the brake master cylinder, which is mounted to the firewall, more or less opposite of the steering wheel. The reservoir should have a full mark and a low mark on it. If it's low or empty, then you need to start looking for a leak. Fill it. Start the car and let it idle while so everyone pushes the brakes every few seconds. Look around the master cylinder area for signs of brake fluid. Take pictures of whatever is leaking and post them here. We will figure it out.

Harry
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Wednesday, March 20th, 2019 AT 8:53 PM
Tiny
MENDYZOEY
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  • 15 POSTS
The pedal feels normal.
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Saturday, April 27th, 2019 AT 12:43 PM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
Okay, let's backup a bit here, because it has been a while since we last communicated. Exactly where do we stand now? Are you driving the car? Does it feel like you have to stand on the brakes to stop?
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Sunday, April 28th, 2019 AT 4:18 AM
Tiny
DAVE213
  • MEMBER
  • 38 POSTS
Yes, I have to stand on it.
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Sunday, April 28th, 2019 AT 4:39 AM
Tiny
HARRY P
  • MECHANIC
  • 2,292 POSTS
If you have to stand on it to stop, and it's not going to the floor, then most likely your brake booster has failed, or the vacuum line for it is leaking.

The power brake booster uses vacuum pressure generated by the engine to boost your brakes. Basically, it helps you push the brake pedal. When it quits, the brake pedal feels just as hard when the car is running as it does when the car isn't running. If you listen closely, you might hear a hissing sound either at all times when the car is running, or just when you're pushing the brakes and the car is running.

Raise the hood. Look where the brake master cylinder is mounted. The brake booster is in there. There should be a largish vacuum line going to it. Inspect it for cracks, leaks, and signs of collapsing when under pressure.

I'll come back with diagrams later on. Gotta take my 3 year old for his checkup. Fun fun.
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Tuesday, April 30th, 2019 AT 5:22 AM

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