72cuttys

Is the pink ignition wire found in the fuse panel 12v while cranking as well as key on? I ask because I am looking for a 12v source to trigger relays for my fuel pump and MSD box. Car is a 71 Cutlass S which has is being LS swapped (don't shun me).

matt69olds

Pink wires in the fuse box should have power while cranking.

This is my go-to meme when all my “Brand X” buddies start bragging about the almighty LS

garys 68&72

Not quite sure what you're asking....are you referring to the pink wire on the 72 harness?
If so, you'll have to check. On these old cars, the ignition may provide the coil wire in run only. During cranking, the coil is supplied through the starter solenoid (ballast resistor bypass). I've seen both kinds of ignition. You'll have to check.

Lonnies Performance

Wiring the fuel pump directly to ignition power is not recommended.

It should be wired through the ECM, which gives it a prime signal for starting & also a run signal. If the car shuts off for any reason, it will also stop the pump.

If going carbureted, i would use 2 parallel relays to control the pump. 1 from the start pin on the starter solenoid & another from an oil pressure activated switch.
This way it has fuel pressure when starting & oil pressure maintains the circuit, but if the engine shuts off for any reason, so does the pump.

garys 68&72

Lonnie is correct. Use an oil pressure hobbs safety switch.

Vintage Chief

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