I've read contradictory posts on here regarding what the oil pressure sensor does that's located just above the oil filter.
Some say it shuts off the fuel.
Others say it throws a light.

I never really thought about it until just today I noticed that one of my birds reads 0 psi (I know the gauges are for looks) at idle and about 12 psi with a generous amount of gas.

Now my other 3 birds all read pegged until they're absolutely fully warm at which point they only drop to about 45 psi.

What does the oil pressure sensor actually do besides get in the way when you're trying to yank an engine??????
I don't know if I should be worried or if it'll actually shut me down while driving to protect itself.

 

there is an oil pressure sender that is at the top of the block, behind the plenum located right behind the distributer, it comes off almost like a brass T, this controls the oil pressure gauge and thats it... its just a sending unit. now this gets alil weird

on my 86TA with a 305TPI and no oil cooler... there oil pressure sender is there but is connected to a T fitting and has another sensor that has 2 male connectors coming out of it... this is the OIL PRESSURE CUT OFF SWITCH. on my 350tpi 87 formula due to the oil cooler it doesnt have it here but right above the oil filter... this switch NEEDS to be connected at all times and working. it senses oil pressure and keeps the car running, if that fails the car will shut off. its a saftey precaution built into all cars running electric fuel injection due to the fact that the fuel pumps run high pressure all the time as long as the key is on the run possition... if u were to get in an accident/engine failure GM put this here so if the engine pressure dropped to 0 or sum really low number that it would shut the fuel pump off, to protect the driver against fires etc say if a fuel line is broken in an accident.

all aftermarket electric fuel pump systems even if its for a carb require the use of a oil pressure cut off switch as a saftey precaution. i kno bc i just installed one on a 79 trans am with a 400 bc he wanted electric fuel pump.

it will not cut the car out on u in mid driving etc as long as u have oil pressure at the engine.

as far as the oil pressure on ur 3 birds... the stock guages are not accurate at all, my stock gauge read 45psi at start and 30 at idle... swapped out the stocker for a 100psi electric stewart warner oil pressure gauge and im only getting 25psi at cold start and 10-15 at idle.... i believe the stewart warner guage since the motor has 137,000 on it stock long block.

btw... who tunned ur setup? and for how much? i cant even get anyone to tune my 383HSR with a compcams XFI 280 with 230/236 .571/.576 lift

 

At least the 91-92 and maybe 90 do not have the sender located at the top rear of the block. That hole is plugged. The only thing is the sender located above the oil filter.

I've been tuning my 383. It's a long on-going process. Everything is running exceptionally well except my (insert as many expletives as you feel is necessary) idle. I'm about ready to bring the idle up and say screw the lope that I desire so much in order to keep the idle from bouncing like a ping pong ball.

 

No it's not, and no it doesn't.

 

Care to explain in more detail?

 

I've heard that the switch above the oil filter runs the fuel pump when the engine is running and shuts it down when oil pressure reaches 0 psi to protect the engine. Thats what I have read. It must also run the oil pressure gauge on my 89 iroc because the is no sending unit on the back of my intake. There's just a plug where the sending unit would go.

 

The oil pressure switch does not shut the fuel pump down on a loss of oil pressure. It's only a backup to the fuel pump relay in case the fuel pump relay fails.

You can prove it to yourself by unplugging the switch. As long as your fuel pump relay is good, the engine will start and run perfectly fine if the switch isn't even installed.

 

Sooooo I should look into a manual oil pressure gauge to verify oil pressure before driving the car again.
The myth of the oil pressure switch/fuel cutoff has been dispelled!!

 

Just replace the sender. The chance that your oil pressure is actually low is insignificant compared to the odds that the sender is bad.

 

I have a 1989 Camaro 305 FI Vin E (TBI)

Apeiron has it right. I monitored my fuel pump relay and found that if the engine was running the fuel pump relay remained actuated the entire time. Since the oil pressure switch is wired in parallel, when the the oil pressure switch senses 6 PSI or more of oil pressure and the engine is running , both the oil pressure switch and the fuel pump relay will BOTH (independently) be sending +12 volts to the fuel pump.

 

The confusion arises from a time when OPS was used as a fuel pump cutout, when it was modified I don't know, my '88 is wired in parallel (backup.)
My oil gauge sender (near distributor) has a single wire connector.
My OPS (above oil filter) has two wires to isolate the 12v from gound, but the connector is a 3-pin.
A single wire switch would need to control the negative side of the fuel pump.

I've relocated the sender and switch, the last reply on the following post about this subject, has a picture of it, I put them on the left inner fender near the charcoal canister.
https://www.thirdgen.org/forums/tech...-pressure.html

 

An oil pressure switch as a fuel pump cutoff switch in case of a collision would serve no purpose. The fuel pump doesn't run continuously when the ignition is in the run position, it only runs as long as reference pulses are received from the distributor. The only time an oil pressure switch would cut power to the pump in a collision would be if the engine was somehow stopped, but that would mean the distributor stopped turning and sending reference pulses, so the ECM would shut down the pump anyway. Likewise, if the engine kept running so that the distributor kept sending pulses, there would be enough oil pressure to keep the switch closed anyway, so the pump would still be powered.

 

My final say on the subject is that my car will not stop running if I disconnect the oil pressure switch.

 

mines the same as rgarcia63, i have the sender behind the distributer as well as another switch which has a 2 wire plug... same on the 86 TA... wat is that 2 wire plug for??? and i also have a sensor above my oil filter in wat seems tobe the block and or oil cooler.... what is that sensor?

i kno that my car does not run when i pull the fuel pump relay... the fuel pump shuts off and doesnt even prime up when the key is turned. wat does the oil pressure switch control and its purpose then

 

 

Ok, you have:

1. the sender behind the distributer; Pressure
2. as well as another switch which has a 2 wire plug...
3. i also have a sensor above my oil filter

Humm... that makes 3

There's only 2 on mine, so is your #2 also Tee'd into the one near the distributor?
This might seem like a rhetorical question, but does #3 have 2 wires as well?
Wire colors would be helpful, pictures even better.