My son and I swapped the cross fire injected 305 out of our 82 Trans Am for a carbed 350. We scrapped all the wiring for the fuel injection and the engine module box. Everything works in the car but the oil pressure gauge. When we first turned on the ignition switch the gauge pegged wide open and nothing we do will make it go back to zero. Even unhooking the battery does nothing. Has anyone else had this problem and if so, what was the solution?

 

Welcome aboard thirdgen.org. Good to hear of another father/son project.

Take the face plate off of the instrument cluster and gently return the needle to zero. They will stick if overdriven.

The most likely cause of being overdriven is a short in the signal line. Have you identified anything like that?

 

Thanks for the welcome. I've read several posts that suggest that I'm supposed to have a tan wire connected to the oil pressure sending unit. I think I have the wrong wire connected to it. The one we connected to it is green. I connected a tan wire to the sending unit that's on the brake proportioning valve which is probably the wire I need to fix the problem. I'll give it a try when I get home today. Hopefully that circuit didn't run through the ECM as we pulled it and the wiring harness that was on the right side of the engine compartment and discarded it. Also, here's a couple of pics of the car. I'll post some of the engine tomorrow.

 

I'll second the welcome.Is the temp gauge working properly.The wire color for it is green is why I ask.On the CFI motors the oil pressure sending unit is located near the dist.The wire color for it is solid tan.The oil pressure sending unit on CFI motors does send a signal to the ECM that the fuel pump is operating but the gauge itself runs off the sending unit.The wire color for the brake warning light is tan with a white tracer.Hope this helps.

Nice looking '82 T/A you have.It's good to see another early 3rd gen.

 

The temp guage pegged out briefly then dropped back down. We have no thermostat in the engine and didn't run it long so I don't think I could tell but we definitely had a green wire running to the oil sending unit and I'm not sure what color was on the temp unit. I'll look at it when I get home but I'm pretty sure we just have them crossed. Thanks Guys!

 

iI was unable to find a tan wire in the engine compartment. Both the water temp and oil pressure sending units had green wires connected to them.

 

OK, here's the 411 on the fix. The oil pressure (tan) wire ran through the ECM. When we removed it and the wiring harness that entered the engine compartment on the left side of the vehicle, we removed the tan wire that would've connected to the oil sending unit. We located the plug that used to hook to the ECM, ran a wire from the tan wire in it to ground and the oil pressure pegged. Then we just spliced a connector for an oil sending unit onto a wire, ran it through the firewall and connected it to that tan wire. It works fine. We now have over 50 pounds of oil pressure when the motor warms up. Thank for all the replies!