1Gina2G
10+ Year Contributor
- 810
- 2
- May 6, 2011
-
Beaufort,
South_Carolina
alright everyone, I recently have had this 7 bolt 4g63t engine fully rebuilt, and recently installed and runs and drives great for the most part. my boost/ vac gauge reads -11/-12 durring idle and the numbers go down as the engine is under load with positive pressure... I understand the vaccum should be more closer to -18 or -20 if im not mistaken.
with that said, I pulled the hose from the breather port on the side of the valve cover, the one that runs strait to the turbo intake pipe; and alot of air is exhausting out from it while the car is under vaccum at idle, which I know it should be pulling in under idle.
with the engine still running, I slowly removed the oil fill cap, and there was no air coming out it was sucking in as it should, could feel the pressure on my hand. with the oil cap back on, I pulled the pcv valve out of the valve cover, restarted the engine with the pcv still attached to the hose for the intake manifold, but detached from the valve cover, and air is getting sucked in through the pcv, appears to be functional. Also a 3/8 100psi check valve is also installed in the same line for the pcv to manifold, and does not leak boost.
with the engine nice and hot after a drive, i took all the spark plugs out and did a compression test, had perfect numbers on all cylinders....
also had my turbo sent out for a rebuild durring the engine rebuild, so i'd assume its good, not an ebay turbo either.
can a boost leak test tell me anything? I know boost is supposed to come out the breather port durring a BLT, which it does, so im not sure what i'd be looking for exactly, ive done boost leak tests very recently both at the turbo and TB elbow and dont have any leaks.
what should I check? thanks!
with that said, I pulled the hose from the breather port on the side of the valve cover, the one that runs strait to the turbo intake pipe; and alot of air is exhausting out from it while the car is under vaccum at idle, which I know it should be pulling in under idle.
with the engine still running, I slowly removed the oil fill cap, and there was no air coming out it was sucking in as it should, could feel the pressure on my hand. with the oil cap back on, I pulled the pcv valve out of the valve cover, restarted the engine with the pcv still attached to the hose for the intake manifold, but detached from the valve cover, and air is getting sucked in through the pcv, appears to be functional. Also a 3/8 100psi check valve is also installed in the same line for the pcv to manifold, and does not leak boost.
with the engine nice and hot after a drive, i took all the spark plugs out and did a compression test, had perfect numbers on all cylinders....
also had my turbo sent out for a rebuild durring the engine rebuild, so i'd assume its good, not an ebay turbo either.
can a boost leak test tell me anything? I know boost is supposed to come out the breather port durring a BLT, which it does, so im not sure what i'd be looking for exactly, ive done boost leak tests very recently both at the turbo and TB elbow and dont have any leaks.
what should I check? thanks!