Fuel Gauge Help

[andyirl]

i have a 2007 1.8tdci i just bought it last week and i have noticed that i had 1/4 tank and the trip comp said i had 150 miles to empty but it seems to move alot i havent done alot of miles since yesterday and its nearly in the red and the light is on nd the trip comp is only saying 35 miles to empty. is this normal is it just moving around or is there something wrong

[jeebowhite]

Probably an issue with the fuel sender unit. I suggest start off by disconnecting the battery for one hour, and then reconnect and see if there is any improvement after reconnecting. Beyond that, I would suggest if the issue continues then you should check the connections at the back of the instrument cluster.

If that fails, ten I would be looking to get the back seat up and check if there is any wiring damage to the sender unit in the tank.

[catmand00]

You really need to fill the tank to brim and ignore the computer but see how many miles you do from full to empty then you can work out how many mpg you are. It may be fuel sender but you may have had just under 1/4tank of fuel and it's just dropped needle due to low fuel.

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[jeebowhite]

I would agree, but the fuel level dropped from 1/4 to just above reserve, which would suggest more of a fault elsewhere.

[andyirl]

Hi guys I put £5 in yesterday to see if it would go up the needle went up to 1/4 tank so maybe I was just low I will fill the tank and see what happens

[jeebowhite]

It shouldn't be that wild in readings and a fiver in a cmax doesn't get far as I recall it's a 53 litre tank so it should not have pushed the needle that far. If a tank took 20 quid and did good mileage I wouldn't have chopped mine in lol

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[andyirl]

What should I do from here

[jeebowhite]

I would say top the tank to brim, monitor the movements, if the gauge is reporting clearly inaccurate information you may find the fault most likely lies with the fuel sender unit.

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[andyirl]

Cheers will try that

[jeebowhite]

If you find it misbehaves, find a good old bumpy Road. Shake the car about and monitor further. I had a sticky fsu, drove a few laps over a bumpy Road and it shook it loose and the issue went away

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[andyirl]

Cheers are they dear to fix if it 8s the

Sender

[jeebowhite]

Hopefully shouldn't be, parts would need to be Ford you could probably pick one out of a scrap motor (same shape and type and refitting should not be too bad. If all else fails, find a scrapyard with the motor and go practice. I will try dig my old Haynes out and see if it had the steps to help you out

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[andyirl]

Cheers

[jeebowhite]

Sorry its taken me a while to get back to you, work has gotten crazy!

Anyway, the Bible of Haynes says...

1) the fuel pump and gauge sender unit is one unit.

You need to remove the fuel tank (3/5 spanners)

1) Run fuel low, or drain tank

To the engine bay....

2) remove fuel filler cap and the fuel pump fuse from the engine bay fusebox and crank the engine a few times.

3) You need ford adapter 23-033 operates like a drain tap.

4) Disconnect the negative of the battery

To the front:

5) Chock the front wheels, jack the car onto axle stands

Now back to the back...

6) unhook the exhausts mounting rubbers from centre rear hangers let the exhaust rest on the crossmember

7) undo the nuts securing the glange and manouver the rear section to one side, secure it with some wire / ties / etc

8) undo the bolts and pull the left hand side air deflector rearwards to release retaining clis

9) undo the rear nuts removing the exhaust

10) release clips, disconnect fuel filler pipe (avoid sharp objects to do the job) depress the release button and disconnect the vent pipe from the rear of tank

11) disconnect fuel supply pipe and evap canister purge

12) support the tank with atrolley jack and large sheet of wood spreading the load

13) note exactly how it sits, how the straps are arranged

14) undo the bolts and remove the straps, but do not lower yet,

15) part lower the tank making sure no pressure on the lines or wiring, when you can disconnect the wiring from the pump and sender, disconnect it, release the clip and breather hose

16) lower the tank as ow as you can.

now to work on the FSU

17) remove any fuel supply pipes

18) unscrew it with with a ford tool, or by carefully tapping it around until you can unscrew by hand

19) take out the rubber seal, lift out the unit, and make sure you dont damage the arm

20) once the units out, measure the ohms, at "full" you should be reading 9 ohms, at empty, around 203 ohms

Refit in reverse...