22r propane turbo PCV/ vac issues

ProbablyBroke

ProbablyBroke

does not torque to spec
Joined
Nov 7, 2012
Location
Reidsville
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I have a propane turbo 22r. Truck developed an oil leak from the front of the motor after 1 road mile. I believe the PCV and catch can were getting boost pressure because of how the hoses were routed and pressurizing the crank case.


There are two nipples for 5/16 hose coming off the intake manifold. When one is capped off and the other is open, motor starts and runs well. When both are capped, the motor won’t start or run. When one is capped, and the motor running, vacuum is present at the open nipple. I’ve blown air into both nipples and can feel it come out the other. Friends with very similar set ups have the nipple capped and no issues. I’m open to suggestions.
 
Have you done a leak down test on the cylinders? Rings okay? Headgasket? If the ports are into the intake then once boost comes in anything after the throttle body will have pressure. I have seen most will vent the crankcase to atmosphere or run the hose to a port on the inlet side of the turbo somewhere between the air filter and turbo inlet which should be negative pressure.
 
Those need to go to the atmosphere. Crank case pressure needs out bad with boost. My old motor would blow the dipstick out of it even with the pcv pulled out and ran straight to atmosphere.
 
You can vent to atmosphere, use a check valve, or move one end of the hose pre-turbo. The last option would be my choice.

I prefer a closed loop catch can whenever possible. It has constant vacuum and is always evacuating crankcase fumes/pressure and it's somewhat proportional as far as boost vs crankcase pressure. That's how my RZR Turbo is setup as well.

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I currently have both ports on the valve cover vented to atmosphere. One port of the two ports on the intake is capped. The other is open. This is the only way the motor will run. As if it will only run with an enormous vacuum leak. I added a 1/4” nipple between the mixer/airfilter and the turbo and ran a vacuum house from the open intake port to the nipple. No start and would immediately kill the motor if connected with the motor already running.
 
What's engine vacuum look like? How about base idle? Fuel pressure? I don't think know much about propane but I assume it's like any other fuel type. Does the mass air meter work or does it even have one? How does it measure air flow?
 
Monkeynono said:
What's engine vacuum look like? How about base idle? Fuel pressure? I don't think know much about propane but I assume it's like any other fuel type. Does the mass air meter work or does it even have one? How does it measure air flow?
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None of that matters on propane. It should either run or it wont.
ProbablyBroke said:
I currently have both ports on the valve cover vented to atmosphere. One port of the two ports on the intake is capped. The other is open. This is the only way the motor will run. As if it will only run with an enormous vacuum leak. I added a 1/4” nipple between the mixer/airfilter and the turbo and ran a vacuum house from the open intake port to the nipple. No start and would immediately kill the motor if connected with the motor already running.
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If I remember ill look at my old turbo motor tonight. Something somewhere is screwy. Draw through setups suck.
 
I forgot about this. So, the one on the intake that is going to the pcv is blocked off on mine. Couldnt tell about the other cause that motor is slammed up against the wall but I got a feeling its blocked also. Mine is 4 barrel and runs holley base plate so its a little different.
 
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