Ive put an old carb'ed engine in my 92 RS Camaro. I need to use a one wire oil pressure sensor but I have the original 3 wire plug from the factory. I cut the tan wire and crimped it on the new sensor and it just maxes out when the engine starts. ANY IDEAS? DO I NEED TO GROUND OTHER WIRE?

 

What car? What year? What engine?
And, why do you "need" to use a 1 wire sensor?

 

OK. The three wire sensor has a separate ground wire and 1 wire sensors ground through the sensor body to the engine. If the ground through the sensor body is good, I would question the resistance of the sensor. The diagram for a 92 vin "T" shows to be 68 ohm sensor. Did you measure the resistance of your 1 wire sensor to see if it compatible?

 

Ohh ok, I didn't check that but it was new out of the box. I realize the orange wire was part of the fuel pump cut off situation. So it has a grey wire, a tan wire and an orange wire. I used the tan wire and its pegging out.

 

For 92 gauges you should juse a 3 wire sensor/switch. 1 wire is 12v, 1 is pressure signal and the other one is for the fuel pump. The middle tan one is for the oil pressure gauge.

Why not just plug the rear china wall and run a stock 3 wire one. 85-87 (?) have a 2 wire one for the fuel pump and a 1 wire on the rear china wall for the gauge. You could have simply reused your stock one and left the wiring alone (if runing a mech fuel pump), for an electric pump it would have powered the FP relay with the engine running (Sees oil pressure), you could have primed the pump with a timed relay wired into the normal ECM FP relay feed to trigger it for a couple of seconds on KOEO.

 

Mine is all simplified bout like a race engine. Simple and sweet. I just powered my fuel pump in with my ignition. Off/on. So i just need to run a power wire and twist it with the tan wire to the sensor?

 

No, the sensor wire is just a pressure related ohmage, the threads provide the ground.

Key on/off fuel pump operation is kind of foolish when all it takes is a stock relay and 1 timed relay (timed normally open, powered/timed closed) When your engine shuts off the fuel pump also shuts off, a lot safer than one that continually runs with key on. Race car wiring is not about simplicity, it's about safety first.