87.5 XTFT4WD turbo update

[skishop69]

Well, I took the TPS apart (very easy) and cleaned it up, no problem. Un fortunately I decided to pursue some other hunches. Comp test: 1-110psi, 2-110psi, 3-130psi, 4-130psi. Oh crap! Let's add insult to injury....

Leakdown test: 1-80% with air escaping to crankcase, 2-60% with air escaping the crankcase AND into cylinder 1; 3&4-15% with no decernable flow (ie, ok). Son of a B*tch!!! There are a few posibilities to cause this...

Cyl 1 definitley has bad rings, cyl 2 has bad rings and either a cracked head or bad exhuast valve or seat. How do you know it's the exhaust valve/seat? I'm glad I asked that... When #2 is on compression stroke, #1 exaust is open. The only way air from #2 can get into #1 is through the exaust since it's ONLY from 2 to 1 and not both ways. Tommorrow I'm going to run a backpressure test on the CAT just for fun and run my borescope down the plug holes. 134K and I could still see the hone marks on the cyl walls. Out comes the engine on Saturday. At least the fix will be cheap.

[geekmonster]

if you want to see if its leaking past the exhaust valve, put that cylinder on tdc for compression stroke and do the compression test. listen in your exhaust pipe for any hissing and/or feel for air. if you hear or feel anything, then you have a nice exhaust valve leak. the same works for the intake valve, but listen and feel on the intake/throttle body open. if you hear a hissing or feel air coming out of the crank case breather, then you have some really leaky piston rings.

[skishop69]

That's what I did. I use my electronic stethescope for leakdows. Much easier. BTW, I grew up in Great Falls.