Vacuum leak detection methods - BMW Forum

BImmerN2B · 09-30-2005, 09:15 PM

I'm trying to find this problem and I believe that is a vacuum leak. It started as a minor abnormal engine vibration and it grew to be a hot rod earthquake. Also the car smells like gas and the RPM stay on or about 1000 RPMS when I let go of the throttle and of course a pronounced MPG drop. Used to get about 390 to 450 miles to the tank and now I get about 330 if I'm lucky.

Just looking to see if anybody had this experience. I pulled the codes before and they read:

P1174 Fuel Trim Adaptation Additve Bank 1 Malfunction

P0505, Idle Control System Malfunction

I basically changed everything except the O2 sensors and the problem has not gone away. I boght a new ICV and it still acts the same. Just wanted to know if anybody had any experience that they can share on this subject.

BImmerN2B · 09-30-2005, 09:19 PM

by the way, car is a 318i 97, 5 speed

thekid · 10-01-2005, 01:44 AM

You can spray carb cleaner or something simliar (don't remember exactly if it is carb cleaner or not...) on to the vacum hose(s). If the engine revs when you spray, then there is a vacum leak there.

BImmerN2B · 10-01-2005, 08:57 AM

GOTCHA KID, I believe you can do that with propane also

used:

thekid · 10-01-2005, 10:19 AM

eh I don't know about propane, i doubt I would try it. I know it is carb cleaner or some simliar can'd pressurized spray. Also keep in mind to move the can slowly, because it takes a second for the engine to respond, so if you move the can too quickly then the source of the leak will be behind where you were currently spraying. Good luck.

someguy · 10-03-2005, 10:31 AM

Carb cleaner for sure......i've used it...works like a champ...just spray and wait to see if theres an idle change.....i would feel unsafe if i used propane....it's not as stable.....