TPI to Carb swap, how can I keep the fuel pump working if I take out my ECM?

 

Most put it on a switch. The couple guys I know that use an electric pump with a carb do anyway. Some are aftermarket pumps, some factory.

 

Using a relay and oil pressure switch are good ideas.

For priming, put a circuit from the "R" terminal on the starter solenoid to the pump. For run, use a relay that is powered closed by an ignition switched 12 volt source. Run that power wire in series to the pump with the oil pressure switch so it will shut the pump off when the engine isn't running.

 

Now, when you say run a circuit to the pump, is there a wire I can splice into that runs to the pump so I dont have to drop the tank?

If I were to just leave the ECM and harness in the car would the pump run then and save me a few headaches?

 

Anyone? If I keep the ECM and harness in, will the pump run or will I still need to rig it up to work properly?

 

I left the ECM in my car when I swapped over to a carb (92 Camaro). It will not only run the pump but it also runs other stuff, depending on the year of your car (it ran the speedo in my 92 which, obviously, I wanted to keep functional for street driving).

I did no special wiring to make the pump work. I did keep the factory oil pressure switch above the oil filter. I'm not sure if that's what kept my pump running while the engine was running, but it continued to work just like stock.

 

The ECM wont run the fuel pump unless youve retained the factory dist. or rigged something up. The dist. sends reference pulses that let the ECM know the engine is running. If the vehicle was originally TBI, then the dash will still work without the ECM, regardless of the year. The easiest way to get the pump to run w/o the computer would be to use five7's method, or do nothing at all, but the pressure switch may not turn the pump on right away while the engine is cranking.

 

The ECM certainly primes the pump for a few seconds at key-on, and probably while cranking on the starter. There would be no way I could have started it with empty fuel bowls in the carb if it didn't. On my 92 I'm petty sure it ran the speedo as well. There certainly wasn't a speedo cable. Agreed that the rest of the gagues don't rely on the ECM.

What kept my pump running while the motor was running I don't know, if it wasn't the ECM. Maybe it was the fact that I also retained the factory oil pressure switch above the oil filter. Maybe that was how the pump got it's power.