Sinking Creek 4WD Association

Got a honda question but it could apply to most vehicles so here it goes. We have a 99 accord 4cyl auto with low miles and good maintainence that is trouble free. Recently when braking it will randomly cut off. It only happens at very slow speeds (almost stopped). It never happens at speed. I am thinking it has something to do with the vaccum on the booster or possibly the idle is too low? Just wanted to get some input before I start trying to figure it out this weekend. Any ideas on what to check.

My girlfriend has a '98 accord that has done the same thing. It just happened to her recently, but hasn't been too much an issue to make it worth finding the problem. I'm guessing it could be a common problem, but don't know much about honda's. Hers is a V6 though.

It sounds as though you have developed a vacuum leak. The idle doesn't change on fuel injected vehicles because it is regulated by an electronically controlled solenoid. The leak causes the solenoid to drive shut, since the engine is receiving all the air it needs to idle through the leak, and upon stepping on the brake petal at low speeds, it causes the leak to stop. Possibly the diaphragm in the booster torn near the edge, sealing when you step on the petal. The idle-air motor (as the solenoid is known) does not act as fast as is necessary for it to maintain the idle, due to programming reasons I'll not discuss here, and the motor starves for air and dies. If I come up with a reason that makes more sense to me later, I'll let you know, but for now this seems the most reasonable. It could also be a broken vacuum line, or even a bad throttle body mounting gasket.

Hmm never would have thought of that, but your logic sounds right to me. I would think you could knock out a broken vacuum line, as your booster should have check valve that would prevent any air from entering it that way unless its not doing it job of course.

i know dodge has this same problem on 4cyl and you can clean throttle body and it clears up

Thanks for the input guys this will give me some things to check.

It ended up being the igniton switch.

alk1174 wrote:It ended up being the igniton switch.

interesting. Do you know what exactly was wrong with it?

It was just worn out. It seemed that under braking and acceleration it would shake the keys which would cut the car off.

how did you figure that out?

That's like the brake lights not working because the glove box wasn't shut....just doesn't add up.

probably similar to GM's PassKey system. If the resistor puck in the key loses contact, the ignition can shut off.

Well it kept cutting off randomly on my wife but never to me, She would just knock it in neutral and restart it so I tried cutting it off and restarting it one day coming home but it would not start back up. So I sat there trying to restart it with no luck. Finaly it restarted so I drove home and sat in the driveway cutting the car on and off for a couple minutes and finally figured out I could barely turn the key back and the car would cut off.