Would readings be incorrect if you placed the oil pressure sending unit at the end of a 3 foot braided steel flex tube ( one end is placed in the front, upper oil galley plug ). So basically it goes from the front oil galley plug to a 3 foot extension then to the oil pressure unit. I have this setup now and I always get insane oil pressure readings from a regular-flow pump. I think this was a bad configuration and that I am reading skewed results because of how it is placed. What does everyone else think? Thanks in advance!

Liberty

 

If I'm reading your post correctly, you might have a problem with the sender ground.

I have a sender inline using proflex myself, and I havn't tested mine yet, but you might need to run a ground wire to the base of the sender.

The braided line is creating more resistance then a straight ground off the block. This will create a higher resistance value at the gauge, giving a false reading.

Ron

 

RonTerry,
Thankyou that is very ineresting! I never thought about that - duh the cast iron block you screw into provides a straight, no resistance (basically) ground for the unit. It is a 1-wire connector. So there is nothing wrong with the setup by nature then eh? Cool. I shall run a seperate ground to the sender's base and check it out!

Liberty

 

Give it a try, and see if your readings returns to normal.

Ron

 

If you subscribe to accepted hydraulic principles and theory, it really doesn't matter how much distance there is from the sensor to the pressure source. Since there is theoretically no flow through the tubing, there should be no pressure drop. Even if the tubing has some expansion, flow to compensate for the expansion would be so minimal that the differential would not even be worth calculating. And this is, of course, on a factory system that we already know is not using laboratory precision components. The problem is almost surely with your sensor connections, not the extension tubing.

 

Vader,

Thanks for the confirmation. Going to investigate soon; first with sensor grounding. Ill throw my results back in here. Thanks!

Liberty

 

What if there were air in the line? I installed a mechanical oil pressure gauge a few (okay, 5) years ago, and used the nylon tube that came with the gauge. (I'll move to metal tubing this summer.) But there's air in the tube... the gauge never said anything about bleeding the tube. My oil pressure is always LOW when the car is warmed up and idling (about 1-2 PSI), but I figured it was because of worn down bearings inside my 233,000 mile 2.8. Could it be because of the air? And how would I bleed the air out? Disconnect the tube at the gauge, start the car, and then try to put the tube in the gauge when oil spurting out? Yipes.