boost/vacuum leak?
12-01-2008, 03:14 AM
#1
Registered
Thread Starter
boost/vacuum leak?
I think I have a pesky boost leak that I can't find. I have a squealing sound I realy don't know were it comes from since I haven't had the car on a dyno and sounds are deceiving when heard from the drivers seat.
it happens at mid to low load, off boost. when I put my foot down it goes away but I have fluttering boost at high rpm.
I have checked my piping and hoses and it all seems good apart from a couple of very small pin holes in some of the welds that may be leaking. I tested them by placing a drop of water on them at idle thinking if there was a leak the drop would be sucked in. the ones I tested didn't suck in the water. but there were a few in hard to get places I might have overlooked.
I have a check-valve on the air thingy hose (forgot it's name
)
there any places on the manifold that can leak?
it happens at mid to low load, off boost. when I put my foot down it goes away but I have fluttering boost at high rpm.
I have checked my piping and hoses and it all seems good apart from a couple of very small pin holes in some of the welds that may be leaking. I tested them by placing a drop of water on them at idle thinking if there was a leak the drop would be sucked in. the ones I tested didn't suck in the water. but there were a few in hard to get places I might have overlooked.
I have a check-valve on the air thingy hose (forgot it's name
) there any places on the manifold that can leak?
12-01-2008, 08:05 AM
#2
You need to pressure test your system with an air compressor. www.boostpro.net/prodtester.html has a tester tool (universal tester), or you can make something similar out of hardware store parts. You would hook up the air compressor, pressurize the system, then listen and feel for air escaping. Spraying soapy water around the engine bay and looking for bubbles helps too.
03-02-2009, 02:00 AM
#5
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Thread Starter
you can give it a go. tell me if it works 
the leak you describe sounds like it has happened to a few people after a boost spike. I'm trying to avoid taking the upper manifold off in search of it but under it is where I think mine is.
the leak you describe sounds like it has happened to a few people after a boost spike. I'm trying to avoid taking the upper manifold off in search of it but under it is where I think mine is.
03-02-2009, 11:35 AM
#6
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I think I have a pesky boost leak that I can't find. I have a squealing sound I realy don't know were it comes from since I haven't had the car on a dyno and sounds are deceiving when heard from the drivers seat.
it happens at mid to low load, off boost. when I put my foot down it goes away but I have fluttering boost at high rpm.
I have checked my piping and hoses and it all seems good apart from a couple of very small pin holes in some of the welds that may be leaking. I tested them by placing a drop of water on them at idle thinking if there was a leak the drop would be sucked in. the ones I tested didn't suck in the water. but there were a few in hard to get places I might have overlooked.
I have a check-valve on the air thingy hose (forgot it's name )
there any places on the manifold that can leak?
it happens at mid to low load, off boost. when I put my foot down it goes away but I have fluttering boost at high rpm.
I have checked my piping and hoses and it all seems good apart from a couple of very small pin holes in some of the welds that may be leaking. I tested them by placing a drop of water on them at idle thinking if there was a leak the drop would be sucked in. the ones I tested didn't suck in the water. but there were a few in hard to get places I might have overlooked.
I have a check-valve on the air thingy hose (forgot it's name
) there any places on the manifold that can leak?
Pin holes can be all it takes. Duct tape to the rescue!
j/k
Last edited by Red Devil; 03-02-2009 at 11:43 AM.
03-04-2009, 08:25 PM
#7
Found 1 largish boost leak and 3 smaller ones . 3 of them around the blowoff valve . I was quite surprised to discover how what looks like a small leak can actually drop your boost considerably .
In fact I would go as far as to say that anyone fitting FI should do this as part of the install .....
Last edited by Brettus; 03-04-2009 at 08:30 PM.
03-06-2009, 05:58 AM
#14
Registered
Thread Starter
I finally decided to try and find the leaks this afternoon. boost leaks first. I rigged up a pressure system out of a couple of bits of round nylon rod. one to blank off sections by clamping it to a coupler in the system and another with a line in the end that could be attached to my bicycle pump since it had a gauge. I found one leak on one side of the intercooler on a joiner. just a small one @ 15 psi. and it took ages for the system to loose pressure.
I'll try a vac hand pump next.
I'll try a vac hand pump next.
03-08-2009, 04:28 AM
#25
Metatron
iTrader: (1)
Brettus, I had a fairly good leak around the blanking plate after I put it in, during Greddy install - the problem is that the plate cants the whole manifold due to it's thickness. I got a leak at the throttle end, but you can also get a leak at the 'ports' end because it is now not mating flat with the LIM.....
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