When testing for a boost leak, with the tester plumbed in after the CCV (toward the turbo) I still get tons of air out the CCV, even on a warm motor. Why is that? The motor is in great shape, with little blowby shown by the oil cap test.

I know I have boost leak (higher EGT's, much lower boost and more smoke with the new ported housing wheel than before), but I'll never be able to find it/them with the CCV preventing pressurization.

Mark

 

That's an indication of low compression. The air is able to get past the rings or valve guides in one or more cylinders. How much pressure are you able to build?

 

I can get about 14psi, and it bleeds down through the CCV. Maybe that's good enough, as I can't find any soapy bubbles anywhere else. I did find one obvious leak, at the fitting for the plastic boost gauge tube. (I despise gauges that use these tubes, and would never buy another one.)

I've never done a compression test on this thing in the 11+ years I've had it, but I suppose I should. I'd think if compression were that bad, the upside down oil cap would come off the filler tube pretty quick, and it doesn't.

Mark

 

There's gonna be some air coming out of the CCV, but you said there was a "ton" of air. How long does it take for the pressure to bleed off after you stop the air flow? When I did mine, I took it to 20psi and it would leak down in about 5 seconds or so.

 

OK, I guess that's about what I'm seeing. Actually mine bleeds down more slowly, but I'm not taking the pressure as high. It actually takes awhile to bleed to zero.

Mark

 

And another little piece of me dies... I did have a boost leak from that infernal gauge, but the real problem was the wastegate arm incorrectly oriented, and holding the gate open. [sigh]

Mark

 

I have to ask... are you putting the boost leak detector straight on the turbo inlet boot, or are you going through the tee to the CCV?

 

Straight into the turbo inlet, with the plastic CCV piece removed.

Mark

 

No accusation... just being thorough. A lot of puff in the CCV? I guess the next test would be to pop the VCs and the glow plugs, then do a compression test. One quickie test would be to rotate the engine one cylinder at a time by puffing each GP hole with air through a rubber nozzle. I've done that, and it's kinduh cool. This was how I found a loose injector the first time - it popped up (bolt out).

 

No worries - not taken as such. I think what I'm seeing is normal, but not what I expected. My naïve expectation was that the intake side of these things is a closed system, and that's just not the case, else there'd be no need for a CCV. I was able to bring it up to 14psi with no bubbles anywhere, so I think any boost leaks have been fixed. 29psi on my boost gauge seems to confirm that, so I think I'm good.

Mark

 

If the camshaft has an intake valve open, you'll get air going past the rings. It'll get through the end gaps in them.

 

That makes perfect sense.

Mark