I have a 1994 F150 300 strait 6. It needed a new oil pump. Was losing pressure and valves would rattle at random times.

I have replaced the pump. Everything is back together. Started it. No pressure. Pulled the distributor. Got a long 5/16 hex rod. Put it on a drill and run it for around 30 seconds. The drill loaded down so I assume I was pumping oil. No oil pressure on the gauge. Chalked that up to low speed on the drill. Hand drills only do a 100 or so rpm. So I put it all back together. Started the truck. Still no pressure on the gauge and valves rattle. I am lost. Any ideas?

 

I hope you installed a mechanical gauge and did not rely on the dash oil psi gauge. The dash gauge only registers @ 7 psi.

Now if I remember right, its CCW for rotation and you should see oil psi even at low rpms. Most prefer using hand drill for safety sake.

Let us know what the oil psi is when running.

 

I put a gauge on it, just to make sure I was getting a good reading. When I turn it with the drill I turn it ccw and it runs quick. I turn it cw and after a few seconds it loads up and the drill slows down. No matter which way I turn it no pressure. Is there some place I can physically see if there is oil flow?

 

Ok, if you remove the oil psi sender, and then you should see if the pump is pumping just by it shooting oil out the sender hole. Having a helper is nice if have one.

I changed mine out on my 300 years ago, so I couldnt remember CCW or CW.

 

Well I have embarrassed myself on that one... Thank you. Going to get my wife to help in just a bit.

 

Did you check the pick up tube and screen for any blockage when you had it apart? There is a gasket that also goes between the block and the oil pump, perhaps it shifted when you installed the pump..

 

We pulled the tube and screen. Soaked it in mineral spirits over night then took compressed air to clean everything. I am worried about the gasket shifting.

 

Wife reminded me that we glued the gasket on with rtv a day before we put the punp back in, so gasket moving is not the problem.

 

Ok, did you have oil pumping out the sender hole when you turned the oil pump with the drill?

 

Sender hole? The hole where the sensor unit is correct? Not yet. I will have to do that in the morning.

 

Yes, where the oil sender screws into the block.