Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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1992 Camaro, 350 carbed. Have the Oil Pressure Sending Unit, which supplies the guage as well as runs the fuel pump (married unit). I want to get rid of this thing...
1) These things don't last long - seems they are always going bad
2) I hate the fact that this OPSU can go bad and allow ther fuel pump to run always, key in or not - would rather rig the fuel pump to a hot-in-run wire instead of a always hot wire.
3) Would also like to rig a switch to cut all power to fuel pump - disabling vehicle (anti-theft)
So my question: Can I install a OPSU from a 1986 car (not married - doesn't run fuel pump - just supplies guage)?
The married unit has 3 wires - 2 are for the fuel pump operation, the last is for the guage. The unmarried unit just has one wire. Is it as simple as connecting the two fuel pump wires together (of course finding a hot-in-run wire for the one side so that the pump doesn't run constantly), and then connecting the single leftover wire to the one terminal on the unmarried OPSU? My guage is 80psi, and there is a OPSU for a 80psi guage listed for a 1986 car.
The two fuel pump wires have to be connected to each other, otherwise the pump won't run.
I got the older unit today, installed it and plugged the single wire to it, and it does operate the guage, although it doesn't have as quick of response time as I'd like.
But the pump will not run without the two fuel pump wires connected together - fuel pump runs from current supplied directly from battery to OPSU to pump. I have no ECM (350 carbed using in-tank pump and Mallory 4309), but even so the ECM and fuel pump relay ONLY supply power to the pump for the 'priming' function - after the 2 second prime no power is supplied to the fuel pump EXCEPT through the OPSU.
Also, if it helps anyone - the fuse behind the battery in the sigle fuseholder seems to only power the fuel pump - at least in my case where I've removed the ECM and I have a seperate aftermarket cooling fan controller
I missed the no-ECM part. If you just connect the wires, your fuel pump wil always be running. You can leave the wires disconnected, and run switched power to the fuel pump relay.
