Can someone please advise? The mechanic who is troubleshooting my car has found a leak but cannot pinpoint where. States it's coming from behind the plenum.

Reason for my curiosity is I've already pressure tested my car for leaks from the lower i/c hoses and has held 20 lbs. for over over 30 seconds and so I am surprised that he even found a leak.. wondering if something might have been overlooked as he smoke tested through the intake opening.

My car's issue is that the boost gauge is reading 0.1-0.2 at engine off/ignition on or when car is at idle. Durametric tells me that my boost pressure of sensor is 1,132 hPa while the setpoint boost pressure and ambient pressure readings are in the neighborhood of 1,010 hPa. Normally, the values will be very similar under these conditions.

The car idles and drives fine until you start boosting, which will then eventually throw the car into limp mode until you shut down the car and clear the codes.

P1136 followed by P0236. Already replaced the MAP, MAF, N75, fuel filter just to name a few...

Thanks in advance!

 

ask your tech if they have replaced ( or inspected ) the #16 check valve at the plenum, which would coincide with your description the area of the suspected "leak".. it is a 50$ piece of plastic, and is notorious for being the source of very hard to isolate leaks on this car. though, usually air can be faintly heard escaping, while pressure testing from the turbo inlets.

just a thought.

 

I actually replaced that #16 check valve as a preventative maintenance item while I was replacing a leaky venturi tube. Also replaced as many of the oe crimp clamps as I could with hose clamps and zip tied many of the small lines. Thanks for the thought tho!

 

good for you, you're more pre-emptive even than i am. there's not a whole lot left at the plenum/tb left to check! but like i said, was just a thought ..gl w it.

 

If you have not replaced the throttle body gasket I would do that while your in there It is a common part to fail on our cars. Mine would not leak until over 10psi. It was hard to find the exact location of the leak because it would just blow the soapy water off and not bubble. Plus the location of it does not allow it to be seen or accessed very well. My 16 valve was broken and one of my little check valves was cracked as well.