Oil pressure sender fail?

Hey guys,

Just got my motor installed (SBC), and upon first firing everything was great except for my oil pressure gauge. I have good ground between the sender and the engine block, and I have oil pressure (I have a fuel cutoff switch connected to the same port on a t-fitting; if there were no pressure, there would be no fuel). I believe that the sender is bad even though it was a brand new unit from cl***ic instruments. I think the sender is bad because the post where the sender wire connects is VERY loose and moves around in the housing. There is a rubber diaphragm of some sort around the post that i believe is detached from the housing allowing it to move around, so that may be the problem. Anyone had any problems with these sending units before?

Thanks!
Phil

 

I wouldn't trust anything but a mechanical gauge for an initial fire up..

There's just too many variables with an electric unit , especially aftermarket .

I'd say 1 out of 20-30 electrical parts are defective in the box

 

I tend to agree - I have a mechanical gauge, so I will be running that to double check everything later today. The motor has already had initial break-in and has been dyno'd, but as you have suggested mechanical is idiot proof haha

 

I agree. You can buy a $25 - 30 Mech oil pressure gauge from Auto-zombie or Advanced-Retarded Auto parts then swap over to your fancy gauges once the engine is broken in. Cheap insurance and something to use while the other one is returned or replaced.

 

I'd say the sender no good. Electrical senders have small wire connected to the post where yoy connect your wire that goes to the gauge. Never over tighten the nut that holds the wire. When you start turninig the post it breaks the wire off inside. Thus no oil preasure. To test your gauge you should beable to ground out your sender wire with the key in the on position and the gauge should go to the max preasure.

 

I had a bad one when I built my pickup,,it's really not that uncommon. HRP

 

Yep, I believe that is likely what happened. Thanks for the info - I did do continuity tests and grounding the sender does peg the gauge at max pressure. I ordered a new sender which should be here this week. Definitely going to do initial calibration etc. with a mechanical oil pressure gauge