PDA

View Full Version : The mysterious vacuum leak!!

confuzed240
06-23-2010, 07:43 AM
So my car has a vacuum leak somewhere. When I first start the car the vacuum is fine and is around 20psi. As soon as the car starts to heat up it drops to 15psi. If the car is left running it will get even worse going to about 10psi...

If I rev the engine it will go back to 20psi for just a second and then go back to 15-10psi.

I have replaced all intercooler pipe hoses, the intercooler, and the BOV so I really don't believe the leak is coming from there. I'm in the process of replacing all the vacuum lines now. Any suggestions would be great.
confuzed240
06-24-2010, 07:42 PM
So the car idles around 15psi of vacuum and when I UNPLUG the maf is running much better around 18psi. Is this maf wiring?
codyace
06-24-2010, 10:01 PM
15 inches at idle isn't bad...It seems like all is fine IMO. Running rich and in limp mode will create more vacuum through timing as well, so don't use that for a bse judgment either.
confuzed240
06-25-2010, 09:36 AM
It will drop to about 10psi if it is kept running. Sprayed the throttle body and IAC with carb. cleaner to help find a leak but absolutly no change. I have no idea where to check next.
codyace
06-25-2010, 10:17 AM
is your base timing set correctly?
confuzed240
06-25-2010, 01:15 PM
The car ran 100% before I swapped injectors, MAF and ECU tuned by Enathply. So I believe the timing would be correct...
greenzenki86
06-29-2010, 04:11 AM
damn someone beat me to it, yeah spraying carb cleaner is the best bet to trace that leak, at least do this before replacing all the lines, save yourself the money first man.
confuzed240
06-29-2010, 10:10 AM
All lines replaced and everything was sprayed with carb cleaner...

Did some more research, I'm leaning toward it being a worn out temp sensor that goes to the ECU, since the car will randomly run at 20psi vacuum then go back into bad idle.
codyace
06-30-2010, 09:47 PM
All lines replaced and everything was sprayed with carb cleaner...

Did some more research, I'm leaning toward it being a worn out temp sensor that goes to the ECU, since the car will randomly run at 20psi vacuum then go back into bad idle.

Did you recently add cams to the car, or adjust the IACV>?