pete95zhn

Need help, urgent.

Facts:
-engine was off
-oil cooler/filter/pressure sensor housing was off
-after installation, when cranking dry (w/o DME relay) no oil pressure
-low pressure light is also on
-oil level caution light is also on, although dipstick shows oil at upper mark
-when cranking the oil pressure needle jumps once
-oli pump works, because the filter is full of oil and releases pressure when loosened

I have tried with two different OPRVs (new model, the engine is MY '89), with new O-ring. My DIY installation tool centers perfectly and I can tighten the OPRV almost to the end with fingers.

So
-is it still the OPRV or misaligned housing?
-oil pressure sensor faulty?
-faulty wiring because oil level light is also on?

How to check wiring the easiest way?

Tom M'Guinn

Welcome back. Long time, so see.

I'd start by making sure you have plenty of oil, then remove the spark plugs (and dme relay) and see if it will build pressure that way. The motor spins so freely that way, it's easier on the motor and builds pressure much easier. If that's doesn't work, I'd try a mechanical oil pressure gauge first just to figure out if you should be looking for mechanical issues (OPRV, pump seal, pick up tube, crank bolt torque, etc.) or electrical (sender, harness, gauge, etc.)

What's the history of the motor? Was it working recently and, if so, what did you last do to the motor? Sure the crank bolt is torqued to 155 ft lbs?

Humboldtgrin

I took out my OPRV and pumped a little oil back to the oil pump so it had a prime to work with. I had the same issue when I resealed my cooler housing. The pump is full of air. You should be good to go after that, if there's no other issues.

pete95zhn

Thanks Tom, I've been lurking at 996/7 turbo boards lately...

Thanks, I'll try that and prime the pump too.

OPRV, pump seal, pick up tube and crank bolt are checked. Electrical side is a question mark because these harnesses are getting old...

It is a relatively low mileage longblock bought for replacement for friend's car while the old engine got toasted. I swapped head and auxiliary/exterior parts from the old one with new seals. I cleaned the block thoroughly but did not remove crank (and oil pump) or pistons. Oil pan was also off and pickup changed. Both blocks are MY '89.

Bolt is torqued.

F18Rep

Probably a long shot but since you mention the crank pulley.... It's fairly easy to mis-assemble the crank bolt hardware so the ps pulley is off center which results sporadic pressure. Just thought....Bruce

pete95zhn

Somehow, for unknown reason, it started to build oil pressure...

I just checked the wiring loom and connections and kept turning it with stater, plugs removed and suddenly the gauge started working. So I added fuel and spark and it runs.
But Oil Level warning light is still on...

NCLA951

Is the pressure sender new? I was getting warning lights with good pressure, turned out to be the dummy light terminal on the sender. Just an idea.

Matt O.

Did you add any oil? If you overfill it, does it build pressure? If so, could be the pickup tube.

pete95zhn

OPRV internals just needed more oil or harness some wiggling, but now the pressure is OK. Pump has worked all the time.
EDIT: Most likely electrical issue, because Oil Level Sensor started working too, without adding any oil.