Author Topic: Automotive question (Read 486 times)

MrCoffee · « **on:** August 25, 2004, 05:33:11 PM »

This question is meant for lasz or whomever if they think they can answer. Its a tricky question. Is there any chance that the vacuum line from the brake booster of a car if it were leaking somewhere at the booster or line affect the performance of the car. Possibly cause it to backfire?

Skuzzy · « **Reply #1 on:** August 25, 2004, 05:37:07 PM »

Yes. Left alone long enough you can burn the valves in the engine.

MrCoffee · « **Reply #2 on:** August 25, 2004, 05:41:22 PM »

Your scaring me skuzzy.

MrCoffee · « **Reply #3 on:** August 25, 2004, 05:48:25 PM »

Well the brakes in this car were spongy and the pedal was droping. This was intermittent and got better and worse then better. The vacuum problem probably originates from the engine somewhere but I wanted to ask lazs that question. Havent found the source yet. Its very wierd. Meanwhile, everytime the supercharger light turns on, the engine backfires and cuts out. This is not my car but it has some serious problems.

NUTTZ · « **Reply #4 on:** August 25, 2004, 06:00:20 PM »

Drum brakes?

NUTTZ

Quote

Originally posted by MrCoffee
Well the brakes in this car were spongy and the pedal was droping. This was intermittent and got better and worse then better. The vacuum problem probably originates from the engine somewhere but I wanted to ask lazs that question. Havent found the source yet. Its very wierd. Meanwhile, everytime the supercharger light turns on, the engine backfires and cuts out. This is not my car but it has some serious problems.

MrCoffee · « **Reply #5 on:** August 25, 2004, 06:02:59 PM »

Booster is for the main master cylinder.

NUTTZ · « **Reply #6 on:** August 25, 2004, 06:08:33 PM »

I know , but your brake peddle is erratic, I had the same problem Power brakes to drum. Peddle was good, then down to the floor then good, then bad, problem was a frozen adjuster in the driver drum. Now that wouldn't fix the backfiring,BUT you may have two seperate problems that you may believe is caused by one. Just an observation.

NUTTZ
P.S> what year,type car?

Quote

Originally posted by MrCoffee
Booster is for the main master cylinder.

MrCoffee · « **Reply #7 on:** August 25, 2004, 06:14:14 PM »

I think thats actually in the drum of the brakes right? Hum, well Im still curious. Vacuum leaks sometimes cause engines to backfire besides vavle timing etc... The brake problem was first then the backfire problem about a week later.

crowMAW · « **Reply #8 on:** August 25, 2004, 08:34:38 PM »

The vacuum to run your brake booster is from the intake manifold. If you have a leak in the intake, the car will run too rich. This can cause the car to idle poorly, stumble under acceleration and backfire (which is a build-up of unburnt gasoline in the exhaust pipe that ignites).

SaburoS · « **Reply #9 on:** August 26, 2004, 12:21:18 AM »

MrCoffee,
Actually, Skuzzy is correct.
If there is a vacuum leak, there would be too much air to fuel, causing a lean condition.
Pull your spark plugs and look at them for indicators.
What year, make, model, engine, etc is the car?

MrCoffee · « **Reply #10 on:** August 26, 2004, 01:51:06 AM »

Actually thats the first thing I did and they look ok. If there is a vacuum leak, it hasnt been long enough for the valves to get burnt. At the moment, I think its either a vacuum regulator somewhere or on the supercharger air bypass regulator something. Could be an electrical switch for an air valve. The supercharger system itself due to what I just mentioned could be in a state where it is causing the vacuum leak. On gas the supercharger does work sometimes, it soars when it kicks in. However when it fails, theres no roar of air coming in and the engine cuts out then backfires. I suspect its the supercharger or a peripheral of it. Air valve, electrical switch, or vacuum regulator. The vacuum may have been affecting the brake booster and thats what I may have been noticing. When the supercharger does work its not making any bearing noises either so I think its just the on/off sequence thats ef*ed up.

MrCoffee · « **Reply #11 on:** August 26, 2004, 01:58:07 AM »

Good thing is I have the manual and was going through that.

Mark Luper · « **Reply #12 on:** August 26, 2004, 04:25:51 AM »

Most backfires I've encountered have been caused by ignition problems with the exception of a lean condition at acceleration on some of the older carburated systems when the accelerator pump didn't keep up with the opening of the secondaries on a four barrel carb.

We all still don't have any specifics of engine, car, fuel system, etc...

crowMAW · « **Reply #13 on:** August 26, 2004, 06:39:54 AM »

>thwaks forhead<

Doh! yes...lean, not rich.

lazs2 · « **Reply #14 on:** August 26, 2004, 08:29:14 AM »

yep... cars work on an air fuel ratio... if you have an air leak it will make the car run "lean".... more air in the mix. the mixture will burn very rapidly and hot. it is like having your timing very advanced. It will be much less noticable at higer RPM or, especially under load where the vacumn is down. transition from idle is where it will be most noticiable including backfiring through the carb (the mixture is burning too rapidly and going back up the intake valve and out the carb).

You need to get a vacumn leak fixed. Start by replacing any old or cracked vacum hoses. hook up a good vacumn guage to the car and see what happens... there are usually instructions with the guage.

good news is..

They are usually relatively easy to find and very cheap to fix.

lazs