Vacuum Leak

[mad082]

this is a bit of a silly question, but can a leak in the cooler piping cause a vacuum leak? my mate has a slight split in his cooler piping and his boost gauge is only reading -10 vacuum instead of closer to 20. i know that the cooler piping has a hose that goes to the idle control valve, but could this cause the loss of vacuum?

i just can't see how it could affect it. your intercooler piping doesn't normally see vacuum as it is created by having the throttle body shut. the only thing i can think of is if it is changing the load of the motor so the idle control valve is opening more.

we are replacing the split bit of piping anyway.

[AdamsR33]

if the turbo isn't boosting then i think so, as the motor is sucking air instead of the turbo blowing it in.

[mad082]

but the butterfly is shut so the turbo doesn't have any affect.

i always thought that for there to be a vacuum leak it had to be after the throttle body. if you hook a vacuum guage up to where the boost controller sits you will never see vacuum since the bov is just releasing the air so it is at atmospheric pressure. there is no vacuum.

[AdamsR33]

good point, so what if you unhook the aac valve so the car can idle, if you put your hand over the turbo inlet would there be no suction at all?

[mad082]

we are going to replace the split hose tonight so we will hook a compressor up to it and see if we can find any other leaks.