I have just started having oil pressure problem I changed out the sensor and put a mech gauge on it. No pressure at idle once warm but no ticking or knocking. Motor was just rebuilt with new crank and bored pistons about 20, 000 miles ago.is it the rod bearings or crank or could it be something else.

 

Pull the pan and see if the pump is clogged. Could be that whatever crap that is sitting in the pan could be getting pulled up into the pump once said crap is heated up.

 

This all started after some bad mixed gas and diesel was accidently put in the tank and was raising the oil level. Now the gas is gone and the oil is fine but the no oil pressure started.

 

Gas is a solvent. So it could have released crap built up in the engine somewhere.I know it was just rebuilt, but pulling the pan to check the oil pump is the first step at this point.

 

Sorry and I just pulled the pan replaced the oil pump and cleaned the extra silicone I used when rebbuilding the engine. It did have about half of the oil sump with the dry stuff the engine knocked loose.

 

So you've already pulled the pan and it is still reading zero pressure? New pump or original?

 

I think that's everything I have done so far sorry I forgot about that, I just finished rebuilding the tranny and did it while the tranny was pulled

 

New pump.

 

Drove to work, on cold start up 45-65 psi oil pressure when it was up to temp 25-35 psi, and after driving for a while 15-25 psi driving and if the gauge is right 0 at stop lights?

 

Pulled pan off again checked crank and rod bearings the crank bearings where not wearing properly so new bearings. Fixed oil pressure but whats normal idle pressure for my 5.9?