Oil pressure gauge not working

[MOMO96Z]

Just had a new clutch put in the car and went to the shop and went for a test drive and noticed that the check gauges light was on and the oil pressure was flat. But the shop people said that the sensor must have went bad. The motor seem to be getting oil because it quiet as a mouse.

[MN6WS6]

No offense man, but if my oil pressure gauge was flat I would have shut the car down immediately.

What probably happened is that the sensor got unplugged while they were removing half of the bottom end of your motor to get the clutch replaced. Either that or they broke the connector going to the oil pressure sending unit on the block. It is right above the starter.

[Rob B (shoebox)]

Because of the way the sensor/gauge works, if the connection was off or broken (open), the gauge would read full high. The sensor on your 96 is located on the back of the block behind the intake manifold (it's never been by the starter ).

I would say they might have grounded it out. That would cause the gauge to read constantly low. They may have pinched it between the bell housing and the block. You might be able to feel back there and trace the wire with your hand or use an inspection mirror to see.

[N20LT4Bird]

Originally posted by MN6WS6
Either that or they broke the connector going to the oil pressure sending unit on the block. It is right above the starter.

The sender is behind the intake manifold on the drivers side of the car. Picture the location of the distributor on a typical small block and move a little toward the drivers side. Thats the oil press. sender.

Rob B is absolutely right, if you disconnected the sender, it reads "full high" or lots of oil pressure. The wire is pinched between the block and the bell housing. Tell your tranny guy to pay attention to what hes doing. Its gonna be a p.i.t.a. to get that wire free. You either have to loosen the bell bolts and wiggle the tranny loose or you have to cut the wires and splice them back together. Its tight in there, so I would bring it back to the dumb arse who sent you away with a bad sensor. Its awful coincidental that you just had the clutch done and the sender with the closest wire to the bellhousing doesnt work

[MN6WS6]

The reason I said that is because a visitor of our local board had the same problem on their car, and said the sensor was on the passenger's side of the block near the starter. Maybe they have a V6 or something.

Of course, it is typical GM fashion to put the sending unit in the absolutely hardest place to get to it so you have to pay their outlandish prices to have it repaired. I miss the old days where you could sit on the fenderwell and fix anything that was broke, and the only thing on the back of the block was, well, just the back of the block!

And why in the world would they make it to spike high if it was unplugged? That doesn't make any sense to me, because the average person would think "oh, the engine's just cold, it will go down"

[Rob B (shoebox)]

It's on the back of the block because, well, that is just where it has always been on the SBC (except for alternate placing by the oil filter).

[MOMO96Z]

Thanks for the info fellas

U guys are the greatest! It was the Sensor, It was broken and that was what the problem was the reason it was not reading.
I replaced, cost $30 bucks for the sensor and me to remove the EGR valve to remove the broken piece of the sensor. 2 hours to plan the method to get to it, and 1hour of my labor to do everything. The key is to cut a wrench in half for the lack of room at the back for the motor and firewall.

Thank's again