91hatchgt

Hey all.. My power break booster had been bad for a while, and I was driving around with no brakes. Finally I decided I would fix it and put in a new break booster. So my brother and I did it, and now when I start the car, it idles real low at like 600 RPM, and when I am driving say I am coming to a red light, and I press in the clutch, it will die..

I have a BBK CAI, stock MAF, BBK 70MM TB, Trick Flow Intake, 1.7 Roller rockers... I am thinking the only reason it ran before is because the vacuum leak from the bad break booster kept the idle up.. and now that It is fixed, it idles too low, and dies on deceleration. Could the problem be my MAF??

I already checked the TPS and it is set to .98 on the dot. I also just had all the vacuum lines ran with new line (instead of the crappy plastic line).. So I don't know what else it could be.. Sorry this is so long, but I have never had a problem with my car until now.. Please help..

Thanks- Joe

silver91gt

just up the idle with the stop screw on your TB.
then unhook your battery to reset the computer, and it should be good.

91hatchgt

on my bbk TB there is no head on the stop screw, it is just a 'stud' I guess you could say, how do I adjust it without ruining the threads on the screw?

creepshow

Shouldn`t your MAF be bigger than your T/b??

stanglx2002

i think your tb is the same as edelbrocks that you have to use a allen wrench on it to turn it

roundman

I would recommend you remove and clean out the IAC mounted on the throttle body as this is what is supposed to control the idle speed if everything else is working right. use some carb cleaner on it to remove any carbon build-up inside it. this thing works in combination with a small hole drilled in the throttle plate to let in enough air to control the engine speed at idle and on deceleration. if you do use the throttle stop screw to increase the idle speed you will need to reset the TPS voltage also.

Tronick

Just a thought, does the new Booster have a vacuum seal when the brake is not applied? I just had to put a booster in mine and the old one leaked badly when I hit the brake, caused same problem.

91hatchgt

I did that when I got my car a few months ago.. And it wasn't that dirty...

I checked my TPS again and it was at 1.15 .. I dropped it back down to .98 and unpluged the battery for like 10 minutes.. It seems to have helped a lot as it no longer stalls, but the RPM's still fall terribly low on deceleration when not applying any gas. I was wondering if I need to adjust my fuel pressure, or my MAF is just holding back too much air..

Yes your MAF should be as big or bigger than your TB, I just haven't gotten around to buying a new one seeing how I just purchased a 2005 Yamaha YZ250 that I now have to pay for.. LOL . Do you think it could be the MAF at all Roundy?