Fuel Pump Iffy, No purring Options

[Chip]

First Start :

Fuel pump not working when ignition turned on. Fuel pump works when connected to an independent battery. Wiring to pump is ok.
Questions:
Shouldn't pump come on with ignition?
Shouldn't pump stay on while vehicle running?

Could it be s relay? Where is the "Main Relay."
Other possibilities...,
Thank you. (IMG:style_emoticons/default/wacko.gif)

[Dave_Darling]

OK, a few things going on.

First, D-jet pump. The way that the stock D-jet setup works is that the ECU will tell the pump to run for about 1.5 seconds when the key goes from "off" to "on". It will also tell the pump to run while the starter is cranking, and any time the engine is turning over at ~150 RPM or greater.

The ECU does this by grounding a particular pin in the four-pin plug on the relay board, making the fuel pump relay close and send power out to the pump.

Your pump was relocated. Sometimes people decide they don't want to bother running new wires through the center tunnel when they move the pump. So they pick some switched power source and tap off of that to power the pump. In these particular cases, the pump would run the whole time the key is on.

So your first job is to trace the pump wiring. Is it going into the center tunnel to connect in to the original fuel pump wiring? Or is it going to the fuse panel directly, or tapping into some other wire, or what?

--DD

[Chip]

OK, a few things going on.

First, D-jet pump. The way that the stock D-jet setup works is that the ECU will tell the pump to run for about 1.5 seconds when the key goes from "off" to "on". It will also tell the pump to run while the starter is cranking, and any time the engine is turning over at ~150 RPM or greater.

The ECU does this by grounding a particular pin in the four-pin plug on the relay board, making the fuel pump relay close and send power out to the pump.

Your pump was relocated. Sometimes people decide they don't want to bother running new wires through the center tunnel when they move the pump. So they pick some switched power source and tap off of that to power the pump. In these particular cases, the pump would run the whole time the key is on.

So your first job is to trace the pump wiring. Is it going into the center tunnel to connect in to the original fuel pump wiring? Or is it going to the fuse panel directly, or tapping into some other wire, or what?

--DD

thanks, Dave. You are so kind to reply. I'm old and frustrated, but want to push on. I believe the red wire is one of four that has been soldered to the + side of the battery cable, runs down the inside of the rocker panel in a 3/4" rubber tube, direct to the + on the pump. The - wire is connected to a bolt on the frame/tube, to the - terminal of pump. I am not dead certain of this, but will confirm today.