almost finished sub tank install - overhead gauge not working

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Oct 28, 2007
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Hi - Just looking for a little help here. I finished the wiring and plumbing for my OEM sub tank install using a fuel transfer pump ala BostonMangler and George's ECU. Everything works except the sub tank fuel gauge.

My overhead console lights turn on with the headlights and dim properly. The fuel pump turns on when I hit the dash switch and starts pumping. Only problem is it won't pump for more than a few minutes (even with the sub tank full of gas). I think this is because the fuel gauge is reading empty so it's shutting off automatically. I understand this is because of the nifty wiring in George's ECU, correct?

Anyway, I'm assuming the reason the pump shuts off without transfering all the fuel is because the ECU thinks the tank is empty. Any ideas?

Thanks!
 

Romer

fatherofdaughterofromer
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I had a similar problem and it turned out I had a wiring error.

Best way to troubleshoot is with a meter and chek the wires at the kickpanel to see what the signals are reading

Is the Empty say empty? - If says empty and it's not try disconnecting that wire and then faking the signal to show not empty and see whta happens, then trace your wiring back to the sender. If its bad coming out of the sender, then you may need a new one.

When checking at the senderm make sure you have whatever wiring you built disconnected as it may be causing the pronblem.

If the signal at the kickpanel is bad, but its good at the sender, check you wiring, if not make sure you have at least 3 gallons of gas or it might be the sender.

Make sure you have a good ground.

Do something similar with the 12 Volt signals.

Was this working finr before and then you wired in the console?
 
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Romer - thanks for the tips. I don't actually know how to do any of those things you listed, but I will learn.

The sub tank was never working. PO installed the tank and fill neck and provided the gauge console. I had to do the plumbing and wiring.
 
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X2 on what Romer said. I dont know enough about georges ECU to solve the problem. Do both sending unit wires connect to the ECU? Where is your sending unit ground connected?
 

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