tk111 Posted 8February, 2014 Report Share Posted 8February, 2014 Advice needed, Whilst on a drive today with some fellow enthusiasts my fuel pump and fuel gauge stopped working and left me stranded. 5 minutes Prior to this happening I did hit a bump on the road at speed and the front left side did bottom out. I am presuming that something came loose or broke at this point and the remaining fuel in the webers got me further down the road. I don't know if the wiring is correct as the car has had extensive work done to it by PO's. The black cable from the Fuel Pump and the Fuel Guage Sensor are spliced together and both run to a ground point on the fuse box. Is this normal? * When I turn the car to the on position neither the fuel gauge or pump are energised. Checking with a multimeter I have found the following: * There is continuity between the positive and negative terminals of the Fuel Pump, IE: I connected a multimeter across the terminals of the pump with no other wires connected and got a solid beep indicating continuity (is this correct?) * If I run the black wires from the pump and sensor directly to the negative terminal of the battery the pump and meter both work. *But if I try and use the ground point on the fuse box to terminate the black wires (as per previously connected) the circuit doesn't work. I believe there is a short coming via the fuel pump because of the continuity. Do I need a new fuel pump? or is this just dodgy wiring? Thanks Link to comment Share on other sites More sharing options...
Pauly Posted 8February, 2014 Report Share Posted 8February, 2014 Make sure the fuse isn't burnt. Yes Ha HA but i've done this many times. Next. Check the ground on the fuel pump. It's usually grounded on the chassis. Fuel pumps usually need a thick ground, and if its aftermarket, you definitely need a thick one. Link to comment Share on other sites More sharing options...
tk111 Posted 8February, 2014 Author Report Share Posted 8February, 2014 Thanks Paul, Checked Fuse is fine. Regarding grounding on the chassis, this is where I am confused. If I ground directly to battery all is good, but if I ground via chassis I don't get 12volts when ignition is on? Even though I have checked there is a 12volt difference from this ground point to the positive side of the battery when ignition is off. It seems as though there is a short being introduced via the fuel pump. Maybe the short is on the positive side of the circuit in the fuse box? Time to check.. Link to comment Share on other sites More sharing options...
Pauly Posted 8February, 2014 Report Share Posted 8February, 2014 So you're getting 12v to the fuel pump? If you are 100% then its a ground issue. Try getting another cable and go from the fuel pump to ground anywhere on the chassis. Their the cable is toast or bad ground. Even try cleaning the ground point for the fuel pump. Use sand paper to clean or a file. Impossible to have a short with ground. If there's a short with +ve the fuel will blow every time. Link to comment Share on other sites More sharing options...
tk111 Posted 9February, 2014 Author Report Share Posted 9February, 2014 Thanks Pauly, you were spot on. I wired direct to the negative terminal and all worked as normal. I think I was over diagnosing yesterday with the multimeter, in the end the KISS principle came to the fore. Link to comment Share on other sites More sharing options...
Pauly Posted 9February, 2014 Report Share Posted 9February, 2014 Glad you fixed it! It's a habit over diagnosing issues. I did that with my interior lights. nearly ripped out my dashboard!! when 1 wire was broken at a clip right in front of me Link to comment Share on other sites More sharing options...
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