Vacuum Leak :/

[mattnz]

So pretty sure I've got a vacuum leak. Closed throttle vacuum is 10inhg, and fuel cut is coming in around 9-10psi.

I've checked the plumbing to the gauges, and the gaskets between TB/intake manifold and intake manifold/intake.

I did manage to strip the one of the threads holding the intake manifold on a while back, didn't make a difference at the time though, so I don't know why it would suddenly start like this if that is the problem.

Is there anything else I should be checking?

[Nick Mann]

Loads.

Pipes for the boost solenoid and FPR solenoid. Dump valve & pipework. Main turbo pipework. Probably more that's not springing straight to mind!

[Davezj]

if you are worried about this then you can do a pressure test all the pipe work.

this a very simplified description of how to do it.

if you have an air compressor then you are half way there.
next you need to make yourself a little disk of the correct diameter (must fit snugly in the flex turbo pipe mention below) with correct air compressor fitting for your compressor.

Test method:-
disconnect the end of the flex pipe coming off the Y turbo pipe. fit disk in there and pressurise the pipe work but to no more that 14psi (this the recommended max pressure for the wastegate actuators in the manual), then check for leaks with a strong solution of washing up liquid and water and look for bubbles.
if you see bubles you have a leak.

[MarkSanne]

^^what he said^^

Last year I made this:

uploaded/1887/1250495884.jpg
uploaded/1887/1250961484.jpg

[mattnz]

if you are worried about this then you can do a pressure test all the pipe work.

this a very simplified description of how to do it.

if you have an air compressor then you are half way there.
next you need to make yourself a little disk of the correct diameter (must fit snugly in the flex turbo pipe mention below) with correct air compressor fitting for your compressor.

Test method:-
disconnect the end of the flex pipe coming off the Y turbo pipe. fit disk in there and pressurise the pipe work but to no more that 14psi (this the recommended max pressure for the wastegate actuators in the manual), then check for leaks with a strong solution of washing up liquid and water and look for bubbles.
if you see bubles you have a leak.

I'm 0% of the way there then :P

Will have a check of the pipework again, didn't really think of the dump valve, so I'll give that a go.

[mattnz]

Would a vacuum cleaner maybe work?

[fuel]

can you hear a hissing noise from anything or any general direction when the engine is running? get a can of brake cleaner and spray it around the joins of the manifolds etc

[mattnz]

Turns out it was the actuating tube on the bypass valve perished by oil. So that's why they had that plastic shielding on it :P

[Nick Mann]

Glad you found it! :D

[Davezj]

way to go, good man, it is satisfying when all your hard work pays off. no you car enjoy the car.

[jb2815]

^^what he said^^

Last year I made this:

uploaded/1887/1250495884.jpg
uploaded/1887/1250961484.jpg


Sweet, this looks good, what's the diameter of that wooden cutout and how did you attach that hose nozzle to it so as to be sealed? Do you need to block up the Y pipes at all or just clamp around the hose and go from there?

[MarkSanne]

Diameter is 61-62mm.
The hose nozzle is simply pressed in a hole I drilled and then I applied a fair amout of hotglue to make sure it's airtight.
All you need to do is simply put in such cutout in the hose that you see, no blocking needed anywhere.