Zero Oil Pressure at WOT

[SnoX]

Hi, quite an annoying problem here..

1997 Ranger 4.0 ohv

Spent the last two days replacing upper and lower intake gaskets, injector O-rings , fuel rail gaskets, and valve covers.

Cleaned quite a bit of crud out of the engine. First drive reveals high RPM drops the Oil pressure gauge to ZERO. After that, it jumps around from zero to normal reading for awhile until it settles back.

Could it be:

1. faulty oil sender switch (messed up on re assembly?)
2. Need an oil change, running low on oil
3. Knocked sludge off into oil pan pickup tube (I really, really don't want to hear this... means dropping the oil pan)

Thanks Guys

 

[tbirdsps]

I'd install a mechanical gage first and verify. The electric gages can have all kinds of problems. Not sure about the 97 but the 92 electric gage is just a fancy idiot light. A loose ground, loose wire or crud at the sensor can affect it.