strange problem

mdrburchette · Post by **mdrburchette** » Wed Jun 20, 2007 3:38 pm

My 72 just started acting a bit strange when I apply the brakes. If I'm at a stoplight and I have the brake pedal depressed, the car starts to idle down and almost cut off. If I release the brake, the idle seems to come back up. Used to, if I pumped the brake pedal, the idle would go up, but now the car wants to die. I know it has something to do with vacuum, but what's going on?

ventura ace · Post by **ventura ace** » Wed Jun 20, 2007 3:52 pm

I'll take a guess. Combination of a brake booster leak and a carburetor that could use a little tweaking. In the past, when the booster leak was beginning, the extra air being gulped down the intake manifold was good for the air fuel mixture, which was set a little rich in the carb adjustments. Eventually, the booster leak worsened, more air down the intake, the the point where there is too much air, and makes it run rough.

Alvon

So Cal Mark · Post by **So Cal Mark** » Wed Jun 20, 2007 9:11 pm

oh lucky you! you get to replace a booster

mdrburchette · Post by **mdrburchette** » Wed Jun 20, 2007 9:39 pm

I don't know how lucky that makes me, Mark, since this will be the second booster on as many cars this year.

But I do have a good booster to swap out! I'll plug the vacuum line and see if that fixes the problem.

So Cal Mark · Post by **So Cal Mark** » Wed Jun 20, 2007 9:43 pm

2 in a yr? you should be able to complete the swap with your eyes closed

mdrburchette · Post by **mdrburchette** » Thu Jun 21, 2007 6:36 am

Ha, ha! I do all my Fiat wrenching blind. It's only pure luck and the help from you guys that it actually works.