Troppo

Ok ,I know there are topics about the oil sensor leaking, ect. However none of them I have seen have discribed how to put a new one in without removeing the dizzy. It sounds like people have, but I need to do this to my C4 and would love to know "the easy way"!

65Z01

If you can get a wrench onto the sensor all is fine; if not then remove the dist.

When removing the dist:
-remove the cap
-mark where the rotor is pointing
-mark the edge of the dist & a corresponding mark on the manifold
-when the dist gear just clears the cam gear, put another mark where teh rotor in now pointing.

These marks will assure easy reinstallation.

trackbird

If you are speaking of the oil sending unit beside the distributor that operates the "check gauges" light, it's not too bad (I just changed mine). Go to NAPA and pick up a sensor installation socket (I want to say it's 1 1/8", but I can look when I get home). Use a ratchet and extension and loosen the old one (remove by hand), start the new one by hand and snug with the sensor socket and extension. I couldn't get anything else in my toolbox (and I own a lot of tools) into that area to loosen the sensor but the socket makes it a simple swap.

Troppo

Thanks guys, I'm hoping I can get that socket on it!.....for now

Muffin

A word of caution: The sensors have a very fine thread, be very careful when screwing in the new sensor. Easy to cross thread, tough to fix when you do. Please don't ask me how I gained this bit of automobile knowledge.

trackbird

Also, there are two sensors that look the same. On my '91 (other years could be different) that sensor only had one pin in the socket. That is for the oil light, not the gauge. If you get the three pin version (the sensor looks otherwise identical) you will have a check gauges light on the dash. Make sure of the pin count in the connector and get the correct sender with the right number of pins.

senorv47

Got both the light and pressure senors replaced by my Mech while I watched and while there was alittle cussing and a mention of converting to being a Ford Man, LOL. he reached them from the drivers side with his leg in between the tire and the frame and lossening of the Dist Cap. He attacked them both from the top with his partner on the pass side for some support in threading them on. But he got them done in 15 minutes.

Troppo

Yeeehhhhaaarrr!! I just unscrewed the oil sensor using a 27mm open-ender, straight on, using pliers to turn it....and it worked!
I even reinstalled it !......Now waiting for the new sensor.....

XR_Strider_GuY

Hi Troppo,
Good to see you joined up on this forum mate. Hope it all goes well for you. Where are you getting the sensor from?

senorv47

Which sensor do you need? I have a brand new light sensor I am not using? On the 88 there are two. One for the light and one for the oil pressure gage

C4boy

Assuming you mean the oil pressure sending unit, just remove the wiper motor and you'll have enough room to replace the sending unit. The wiper motor's easy enough to remove.

Troppo

Thanks for the offer, but I've already ordered a new one.
Hi Gary, A lot of good info in here, thanks for the tip!
I ordered from USGM (Dave)....2 weeks ago..

Skoooby

My "Check Gauges" light illuminates infrequently and I was told it is a bad oil pressure sensor.

Can someone please explain to me what is the difference between a sensor and a switch, and what is the sending unit?

Also, can someone please write the p/n for a 1996 oil pressure sensor?
I want to make sure I am ordering the right one.

Thank you all!

trackbird

The sensor generates a variable output that the gauge translates into the various oil pressure readings it displays (the sensor is a resistor and it's variable based on oil pressure). The switch is "on or off" and turns the light on or off based on if it has enough oil pressure or not. The switch is used to turn on the "check gauges" light, the sensor is used to run the oil pressure gauge. The switch has a single pin for the output (though the connector looks like the three pin connector for other GM oil pressure sending units...just without the other pin holes). My local NAPA store looked up the two units and ordered the switch for the light instead of the sender for the gauge. They should list both.

Skoooby

Thank you.
It means that if the oil pressure sensor is bad, it makes the switch go crazy and then the light on my dash illuminates. Is that correct?

I found this for AC Delco:
http://www.bestvalueautoparts.com/Re...h_W_Light.html

The first, the second and the last items on this link show the same part, so do you know why there are listed separately and their pics are from different angels?

trackbird

The sensors look the same, the main way to tell them apart is the connector. They show connectors there, but they are all 3 pin. The 3 pin connector is for the gauge (if you only wired the center pin it could work for the oil pressure sending unit, but it's not the "correct" connector). I know NAPA listed both for my '91 and had it for me in a day (if you're in the states, I didn't see your location). Might be the easiest approach. The sender for the gauge was about $25, the one for the light was about $10.

rodj

Wrong
On a '86 ;the single wire "big can" sender is the gauges sender ;
the separate 2 wire switch is to run the fuel pump should the pump relay fail
Later ('88 +? ) cars have a single 3 wire unit combining the switch and gauges sender
while ('91+? ) have a separate 1 wire unit for the analog OP gauge as well as the 3 wire unit mentioned

Corvette40

The 88 has the same single blade canister type oil pressure sender that the 87 does. The longer black two wire switch is the oil pressure switch. When looking to replace the pressure sender on my 88 they kept giving the the 89 and up 3 wire switch that incorporates the pressure sender and pressure switch in one device. I asked for one for an 87 and it has been working fine for 2 years now.
When I replace the engine next month, I'm going to install the three wire switch down by the oil temp sender by the oil filter like the 3rd Gens have. We just did this on a FIRST install and it works fine.

Corvette40

Did it this exact same way. It helps if you have small hands too.

trackbird

I guess I should have specified that this was on my '91. The "can" style sender is one I'm familiar with from an old '87 Camaro (and my days working in parts stores).

When I disconnected the single wire connector on my car, the check gauges light went out. This was because there was a 3 wire sender in my engine that had two pins bent over and the third pin was grounding the check gauges light (normally open switch in the "wrong" sender and normally closed in the proper single pin switch). The oil pressure gauge (on my '91) worked just fine with the single wire connector unplugged (and the check gauges light went out since it was no longer being grounded by the incorrect sending unit). This leads me to believe that the 3 pin connector has the oil pressure gauge and the fuel pump switch "rolled into one" and the single wire connection is for the check gauges light.

DISCLAIMER: This is on my '91 and may not apply to any other year.