Rb20det has no vacuum and wont build boost

[pilchera]

Okay my rb20s oil pump went out recently. put new pump,rod and main bearings and put motor back in. all intercooler piping is tight, and all vacuum lines are hooked up..

boost gauge stays at zero. you can hear turbo spool driving but will slowly go to 5lbs of boost when your in it. wont idle. doesnt so vacuum on boost gauge

*** what ive tried...
spray starting fluid on all inj.. all vac lines... all intercooler pipping and intercooler.
no change .

also hooked a smoke machine up to it, and couldnt find any smoke coming out any where..

any ideas?

[pilchera]

all cylinders have between 130 and 140 compression
except for number 3. it shows 2.5psi
did a leak down on that cyl and it will hold 95 psi all day long?


ideas anybody?

[gretz]

Blown piston in number 3 by the looks of the 2.5psi compression...

[pilchera]

but if it had a blown piston how would it hold 95 psi with the leak down tester on it?

[xxsptcuztomsxx]

Timing issue? Break out the ol' timing light.

[pilchera]

if it was timing would not more than just one cyl be f'd up?

[xxsptcuztomsxx]

Timing could cause you not to build boost...its worth a shot bro...just takes a couple of minutes to check. In the amount of time you took to post your last message on here you could have actually physically checked your timing rather than speculating. Check out the troubleshooting guide of the FSM.

Regardless, there is something wrong in cyl 3 that will require a tear-down...i suspect youll find your issue while taking things apart.