whenever i start up my 2000 toyota echo it would always make a loud vacuum noise for 20-30 sec. then go back to normal. what causes this?
whenever im driving and coming to a complete stop or in the middle of stopping the brakes would always get hard and i would have to step really hard to stop the car or shift to Neutral and the brakes would go back to being fine (but then the engine would make the loud vacuum noise again for 20-30 sec). there’s more, after coming to a complete stop (foot still on the brakes) while in Drive, the engine shakes like its going to die, if i let go of the brakes a little bit the car jumps forward (like when someone steps on the gas, then brakes, then gas, then brakes, etc.), but when i step on the gas and accelerate the car goes back to being fine, UNTIL i slow down again. please help im running out of ideas.
I WANT TO NOTE THE FOLLOWING: this problem only happens when the engine is warmed up not when the engine is cool. the check engine light only says that the car is misfiring, so if it is can u tell me how it causes the brake problem. i’ve already changed the MAF sensor, brake booster and valve and pipes connecting to it, spark plugs, throttle body, and the throttle sensor. i’ve already called to check for recall and no luck…
You may have a defective power brake booster. This unit operates on engine vacuum and if it isn’t giving the proper assist, the brakes will be harder to operate. Also, a vacuum leak will cause the engine to run poorly.
Well I replaced the brake booster n still same prob … I checked for vacuum leaks n every thing was where they were suppose to be n I checked for cracks too
There is a vacuum leak somewhere and it is enough to cause the power brake booster to lose its assist. I thought ther brake booster was the solution, but apparently it wasn’t. It’s time for a real mechanic to come forward on this board.
I think your problem is still in your booster, but it may only need an adjustment. There is a rod that sticks out of the booster and into your master cylinder. This rod may need to be adjusted so that it barely rests against the master cylinder.
Another remote possibility is the master cylinder itself.
If it was either of these, you should be experiencing excessive brake pedal travel, that is it goes almost to the floor before you get any brakes.
It could also be the check valve, you said you replaced it, but are you sure you didn’t get it in backwards?
When you replaced the booster, was it with a new one, a reman or one from a salvage yard? Everything is pointing to the booster.
thanks for all the info. i’ll check it out. can u guys think of anywhere else where there might be a leak?
A misfiring engine will have poor vacuum and the misfire may not be caused by a vacuum leak. If you believe the the brake booster is leaking disconnect it and plug the hose, see if the misfire goes away. If the vacuum leak is at the engine you should be able to hear it, use a 3 foot pice of hose, (about 3/8" diameter) one end to your ear and the other end to probe around the engine for the sound of an air leak.
However, I would inspect the coils and do a compression test.
i’m completely stumped. i know that it is the engine that is causing the low vacuum but i can’t figure out where else to check engine.
Last ditch effort while knowing nothing. Put some stuff in the oil that says “frees stuck valves or frees stuck lifters”. It won’t cost much except for an oil change that you might do after a couple days. DO: read the instructions on the can. Brake booster diagnosis in in a Haynes manual.