D40 Fuel gauge readings weird.

[GunMentalGrey]

Hi all, my 2007 STX fuel gauge seems to have changed. In the last few months it seems the gauge doesn’t drop in accordance with fuel usage. That is, it used to slowly drop but now hangs around at full for much longer then drops quickly. It was still showing over full after about 150km last fill.

On previous vehicles this was a sign the fuel gauge sender was on the way out. On a Falcon I had it’d read full for ages then drop from 1/4 to empty in about 50km.

Other thing is I’m back priming the fuel after an overnight break. I’ve recenty replaced the primer bulb and vacuum hoses that were bad. It’s possible I’ve missed something, but could the fuel sender/pump failing allow fuel to drain back to the tank overnight?

TIA

 

[Old.Tony]

The easiest way to find a leak in the fuel system is to prime it. And prime it some more. And do it a little more just to be sure (and if you do it on March 17th, to be sure to be sure).

Overpriming the system will pressurise it enough for diesel to start leaking out where your leak is. If it's in the fuel filter itself, check that the water sensor's electrical connector is lined up with the knurled knob (it has to click into place when being refitted).

 

[OldManBeard]

On previous vehicles this was a sign the fuel gauge sender was on the way out.

I'd be prepared to bet that's going to be your answer this time as well. There are a couple of faults with the sender that can cause this but either way, it's probably time to get a replacement.

 

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to test the guage PULL OFF single wire at sender unit which goes back to guage ,(check to see needle go to empty ) , then earth it, needle should smoothly go to full and stay in full position until you REMOVE wire from earth, then needle will drop to empty .if needle is misbehaving check that the wire is not freyed somewhere. so guage is okey then its probably sender unit