A few questions about a burnt up plug on one of my harnesses in my 88 TPI Lb9. This harness is a sub-harness from the big one, it has 3 leads total. 1) for the oxygen sensor and 2)a plug that goes to a sensor of some type just on top of the oil filter 3)the damaged one that was hanging loose in my motor bay, it is a black wire with a white plastic connector. Where does it go? Also, what is this sensor that goes just above the oil filter? I thought the oil press. sender was the one behind the distributor, a little bell shaped thing. Thanks for any help!

 

The thing above the filter is an oil pressure switch, the fuel pump wont run unless there's oil pressure. The switch is nothing more than a relay, the difference is that it uses oil pressure as a trigger, instead of a 12V signal like a normal relay, kinda neat actually

As for the black wire, all I can do is list all the black wires in the ECM harness.

#1 MAT, TPS, CTS 5V reference, this wire is spliced down to one from all those sensors..

#2 Spark retard signal, comes out of the ESC and goes srtaight to the ECM.

#3 Analog ground, straight from the MAF to the ECM.

#4 MAF burn-off control, comes right off the burn-off relay into the ECM.

That's all I could find, my Haynes manual isn't incredibly detailed

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Shane McConnell
macgyver@nethirdgen.org [*]Owner of a 1991 Camaro RS, 305 5-speed.[*]Owner of a 1979 Camaro Z28, 350/350.[*]Webmaster of www.NEThirdgen.org

[This message has been edited by Macgyver (edited September 17, 2000).]

 

You got it Mac! It was the CTS sender plug. I actually figured it out later that day while pressure washing out the inside of my engine bay and inspecting the removed cyl. heads senders and wire harnesses. I should have guessed, the temp gauge has never worked since I bought the car a few months ago! Thanks for the help!

 

A note on the fuel pump oil pressure switch -actually, the fuel pump will run without oil pressure. The ECM controlled fuel pump relay and the oil pressure switch are wired in parallel, so either may run the fuel pump independently.

The only reason I can think that the oil pressure switch is there is for redundancy if the relay fails, or maybe for push starting??? Any other thoughts?

Tim

 

Oil pressure switch is for redundancy... my fuel pump relay was bad, and I had a code for that, but my oil pressure switch allowed my car to start anyways. Replaced fuel pump relay, code went away, car started fine. When the fuel pump relay was bad it took a bit longer to start