Fuel pump help, Please.

[1985BuickGN]

Just installed a speed-pro/fast system, had it on another car and had an external fuel pump on it then. This time I'm using the in-tank pump and the fuel pump won't run now. I tried changing it in the computer (it's off now) but apparently I'm retarted and can't get it. Need to know how to turn it on. Using C-com version 1.40. Thanks, Paul.

 

[bobc455]

Wiring is gonna be basically the same- the SpeedPro is going to provide a ground to the relay that activates the fuel pump.

-Bob

 

[turbodave231]

fuel pump is a high side driver.....ecu supplies 12v.

DR

 

[1985BuickGN]

Did some checking on the Fast site and saw that I need to run a ground from the Fast to the stock relay (passenger side fenderwell next to the MAP sensor) only I don't have a clue as to which wire it is. There is nothing in the literature that I received with the system (I saved everything). Can anyone tell me which one it is, also which one is for fan control? Thanks, Paul.

 

[1985BuickGN]

Tried the stock computer, and turned on the key but did'nt try to start and the fuel pump starts right up, good pressure. Looked at the literature with the system again, and all it says to hook up is the fuel injector feed wire, map sensor tie-in, 1 power wire to battery and 3 ground wires to battery. Nothing about fuel pump or fan control.

 

[1985BuickGN]

Anyone? Anyone?

 

[suns68]

1985buickgn !!!

i have a way to get your wireing sca matics !!! i had same problem for a little while !!! if ya still need help yell at me !!! suns68 !!! im runing a 89 firebird with the fast and procharger ,, this was one of my biggest problems !!! later suns68

 

[1985BuickGN]

Well, at this point, I'm ready to just bypass the stock relay and wire in a new bosch relay and feed the pump direct. I called the place I bought it from and they were supposed to fax a diagram, but nothing yet. Was wondering if anyone knew if this would hurt the pump or drastically shorten the life of it running continuously. It's an in tank Walbro 340. Thanks.

 

[1985BuickGN]

Solved, thanks to Harry at Precision!

 

[Craig Smith]

The fuel pump output switches to ground to activate a relay, as does the fan output. The pump output is pin S3 and the fan output is pin R3.

I see that Harry got you squared away but thought I'd pop tis up in case it was helpful at all.

 

[1985BuickGN]

Hey, thanks Craig, I got the fuel straightened out and the fan was my next task. Thanks for the info. If anyone wants to know how to wire up the relay, I'll try to explain it the best I can. Here goes: First get a standard bosch relay. Next find wire S3 on the fast harness and run a wire from #85 on the relay to this wire, Don't cut any wires, just tap into all of these. I soldered my wires onto the fast harness right at the connector. 2 can go directly to the board on the fast harness and 2 will solder onto the wires themselves since there is'nt room on the board. Next find Buick wire A6 (it's marked on the plastic factory ecm connectors) then find this same wire on the on the fast harness and run a wire from #86 on the relay to this wire. Again, solder it in no butt connectors or cutting. Next find Buick wire A1 (factory connector) then find it on the fast harness and run a wire from #87 on the relay to this wire and solder together. And last, find Buick wire C16 then find it on the fast side and run a wire from #30 on the relay to this wire and solder. Tape everything back together and make sure stock relay is still hooked up and then turn on the key. You have fuel! Hope this helps.