I have a few wires that I need to hook up to make my ram jet ocmputer function. Here are the wires that I need to hook up;

1) 12v
2) Ground
3) Fuel pump signal
4) Fuel pump ground
5) Ignition
6) Tachometer

OK, 1,2,and 5 are easy. But, do I even need to hook up 3 and 4? The car is an L98 car and already has an adequate fuel pump that is controlled by the stock ECM. Do I even need to do this? I think they put these wires on there for applications where a stock EFI fuel system wasnt available and they need a way to turn the fuel pump on and off. I dont know.

OK, the Tachometer wire. How do I get this hooked up to me stock tach? By the way, all of this is in an 89 Formula 350. Thanks in advance.

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L98, 3.27 9-bolt, Hooker shorty headers, custom 2.5inch Y-pipe, no cat, 3inch 2chamber flowmaster, JET AFPR, Ported MAF, Best ET: 13.86 @100mph. 1.99 60'
17 inch ROH "ZS" wheels. 17x8.5(front) and 17x9.5 (rear). Firestone Firehawk SZ50s. 245/45/zr17s and 275/40/zr17s. T56

On the way... Radar Blue 89 Formula, T56, Ram Jet 430, Ram Air, 17inch ROHs.

 

Anyone have any idea?

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L98, 3.27 9-bolt, Hooker shorty headers, custom 2.5inch Y-pipe, no cat, 3inch 2chamber flowmaster, JET AFPR, Ported MAF, Best ET: 13.86 @100mph. 1.99 60'
17 inch ROH "ZS" wheels. 17x8.5(front) and 17x9.5 (rear). Firestone Firehawk SZ50s. 245/45/zr17s and 275/40/zr17s. T56

On the way... Radar Blue 89 Formula, T56, Ram Jet 430, Ram Air, 17inch ROHs.

 

Are you leaving the stock ECM connected? It won't run the pump unless its getting ignition pulses from the dizzy.

I'd run the fuel pump using the Ramjet ECU.

Run the trigger wire from the RJ ECU to the existing FP relay.

I'm not sure what the FP ground is for. The pump is grounded back at the tank.

The tach wire should come right off the ignition coil the same as stock. (Small cap HEI)

 

Yeah, your right about the fuel pump wires. Ill run it with the MEFI3 computer. Thanks. Anyone know which wire in the fuel pump relay plug is the Hot one and which one is ground?

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L98, 3.27 9-bolt, Hooker shorty headers, custom 2.5inch Y-pipe, no cat, 3inch 2chamber flowmaster, JET AFPR, Ported MAF, Best ET: 13.86 @100mph. 1.99 60'
17 inch ROH "ZS" wheels. 17x8.5(front) and 17x9.5 (rear). Firestone Firehawk SZ50s. 245/45/zr17s and 275/40/zr17s. T56

On the way... Radar Blue 89 Formula, T56, Ram Jet 430, Ram Air, 17inch ROHs.