I recently purchased a 95 Bronco with a 351 and yesterday I noticed that the oil pressure guage was pegged (way past high). When I turn the engine off the needle stays pegged, but when I turn the key to the "on" position, the needle drops down into the normal range. Then it pegs as soon as I start it. Is this a problem with the guage or is it something bigger?

P.S. This is my first Ford, so I am new to this world.

 

Sounds like a bad oil pressure sending unit. An easy fix.

 

The fact the oil pressure gauge Pegged means that a direct short has happened.

I would first trace the wire back from the sender and also check for a pulsing current being present with the key in the run position.

It is probably the sending unit though.

 

Dennis
That style (pulsing) gauge wasn't used after '86. The new (balanced) gauges have a switched hot, a ground, and a sender terminal.

It's still the sender or the sender wire, though. Pull the Wh/R wire off the sender low on the L side of the engine just behind the PS pump. If the gauge drops, it's the sender. If it stays pegged, it's the wire.

 

I was sure that said 85 not 95.

I got my magnifying glass to check ...sure enough 95.


Sorry Bout that

 

Sure enough, i've got the exact same problem as you do. Just in reverse. My oil pressure gauge stays pegged below the L mark, and very rarely, it will come up to normal.

I'm going to install a mech gauge, and replace the sender, so that i'll have double the insurance.