Low Vacuum and Fine Idle
This started a couple weeks ago. Right around the time I redid my catch can, breather, and had that last line on the brake booster pop off.
I've checked everything half a dozen times now, and everything appears to be connected properly and working. Trouble is, my vacuum still sits around 10 psi.
Idle is 800 RPM.
Stock gauge sits at 0 with engine off.
DSP confirms gauge's reading of 10 psi vacuum at idle.
If I pump the brakes while switching the AC on, brakes go stiff as it reaches 0 psi.
Emptied half a can of carb cleaner on all the vacuum lines I could find, plus IM and TB. Couldn't hear a difference.
Ran water all over the engine, hoses, etc while it was running, still couldn't hear a difference.
Been trying to do a boost test. First attempt got to 5 psi before I found a leak at the turbo side of the intercooler. Couple turns of the worm gear fixed that. Managed to test boost up to about 15 psi before I found a leak in my tester's threads themselves. Still got to fix that.
Recirc changes the AC fan sound when fan is on max.
On the street, if I push the boost hard it'll spike 20 psi no problem. (DSP tune)
Idle A/F is around 14.7ish.
If I pop the PCV line off at the TB, idle jumps and then settles down. Reconnecting the line then nearly chokes the engine until it settles again.
I'm at a loss with tracking this issue down. Messing with the PCV line and breather, neither is clogged or leaking. I don't believe my IM or TB has the leak either.
Boost test showed it holding 5 psi just fine and I couldn't hear any leaks this way. Does that mean the boost lines are probably good, but it's a CV protected vacuum line somewhere?
Once I get my boost tester fixed, I'll see about testing up to ~18 psi without any noise.
I've jiggled, shoved, and yanked every line I could find, and no change in engine sound.
At this point, I'm thinking I'll just have to start replacing vacuum lines with silicone until it's fixed. Is there anything else I could try? Could something be clogging a line or CV somewhere???
3" TBE, DSP, Meth, AGP 3" CAI