nofalls

After two years of slowly searching, pressure testing while spraying Snoop leak detector or soapy water, pinching off lines with a guage attached in different spots and generally praying to the Prosche Gods I found it. I was getting ready to install my new Laust vac manifold when I pulled out the recirc valve and blew into the pressure side. Not the first time I've done this but why not? It leaked a little. In went the forge knock off that has been sitting on a shelf for a year now. I decided it would be best to only change one thing at a time and make sure it was going to work. 18-20 inHg was showing at idle this morning during a really nice drive into work. Happy day! Now onto that manifold.

Black51

How much vacuum were you seeing before that?

nofalls

10-11 inHg on the pillar gauge at best. The gauge on the dash would dip to the .4 mark if I engine braked on the off ramp in fourth.

Black51

Oh wow, that's terrible. Any driving symptoms? Lazy turbo? Low power? Etc...?

nofalls

Power was good. Boost seemed to max out at about 10 psi though. I am curious to see how the plugs look after a week of driving it. They always looked too dark and oily to me.

pr951

Is the recirc valve you fixed the black plastic valve looking thingie in front of the throttlebody area? And how do you test it?

adrial

Apply suction to the small port on the top of it. It should move the valve and not leak.

You can use your mouth to do this ... just don't spit up into the valve... hah.

Ben951S

Is that the round guy? I should check mine... 10-12inhg at idle... sucks.

Triple_T

Good work!
So, what exactly were the symptoms of this leak? Beside the 10psi max?

nofalls

Yeah, the round guy, with the vac hose coming off the top, plugged into the Jboot.

Just the low vac readings and boost loss. I suspect the diaphragm leaked and I never knew it. Iirc I never pinched off just the line to the valve. Because I could push air through the valve on the pressure side with my mouth (about 1 or 2 psi) I know it had to be bleading boost.