fuel gauge dropped

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jay572

New Member
Posts
100
Location
liss hampshire
hi
i have a td5 discovery 2 2001 model, today when driving the fuel gauge suddenly dropped the orange light came on and thats were it has stayed. i haven't lost fuel as i have driven it all day. Is this a common problem?? also is it more likely to be the sender unit?? can they be bought separately? if so nis there any test i can do to check this. would it be a big job as well many thanks jay
 
ah great thanks for that, do you know if they are prone to going wrong? can i test it in any way?


I've not had any sender problems with TD5 and I've had a fair few through my hands.

To access the top of the tank and therefore the electrical connections you need to lift the carpet in the boot and remove the access trap.

At that stage you will be able to access the connector between the pump and car loom.
 
just had exactly the same prob on my td5. yet to sort it, but apparently on rave under fuel gauge sender unit there are some ohm readings to check.
 
hi
just to let you know ALL SORTED thanks for your help.

So just driving along fuel gauge drops and orange light comes on. lifted carpet accessed top of fuel pump disconnected wiring plug and put multimeter across the two smaller wire terminals nothing, no resistance. so removed fuel pipes and fuel pump inside fuel pump you can trace the smaller wires back to the sender unit were there are two soldered connectors to the resister tried multimeter there got resistance which changed when sender arm was moved. Then noticed one of the wires which should of been soldered to the resistor wasnt!!! re soldered then checked resistance from pins on top of fuel gauge all ok just refitted pump fuel lines and purged air out of system fuel gauge all working again YIPPEE I,ve mended something without cost!!!!!!!!! Also fitted EGR kit WOW a big difference....... many thanks to you all
hope this helps anyone.
 
I have also had this.

I hope this helps anyone who has the same problem.

The fuel gauge suddenly went from 1/2 full to zero with fuel warning light on.

I accessed the pump sender unit under the rear floor carpet and removed the cover.

I removed the four wire electric plug. Tested for voltage on the thin wires ( thick wires are for fuel pump ) Voltage was there at 5 Volts.
I put a 100ohm resistor across the two thin wires in the underside of the socket. Then checked the fuel gauge , this was now showing 1/4 full.
So I knew the wiring was all OK.

Measured the resistance on the sender pins on top of the pump unit.
No reading and was open circuit.

I then removed the pump unit from the tank.

I measured across the variable resister unit and got a 200ohm reading.
When I looked at the connection on the resister unit where the two blue wires are soldered,
one connection had come unattached (dry joint ).

Re soldered it back on. measured again on the top pins and all was fine.

Pump refitted and all back to normal.

Makes you wonder how many pump units have been replaced because of this fault.
 
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Apologies for opening an old thread - but it seemed a good idea to have all the info in one place....

I had this problem at the start of the winter and lived with it until recently.

I finally summoned up the courage (I'm just a DIYer). I did not take notes or pictures - it was quite daunting for me so I just wanted to get it done - but here are some, hopefully, useful points:

See points 1c, 5a and 8 for bits you might want to buy before you start.

1. This is not a small job - you have to lift the back carpet - this means taking out the seats/storage - just getting down to the metal floor plate took me over 2 hours

a. You will need to undo both ends of the 'middle' seat belts (19mm socket)
b. The seats will need a 12mm socket
c. You will need some form of trim tool (I made one out of an old plastic loyalty card)
d. I took the opportunity of cleaning the panels whilst out of the car.

2. If you have the foldable rear seats this is a good opportunity to lubricate them - you will have much easier access to see why they are such pigs to put in place.

3. When you finally have the carpet up and the floor plate out, clean it up thoroughly - it will be full of dusty grime and you don't want this falling into your fuel tank.

4. To remove the pump/sender you will need (or need to fashion) a special tool to undo the collar holding it in place. It does just undo anti-clockwise but it will be stiff - I ended up using a very large pair of plumbers pliers and a screwdriver - do not lose heart, it does come undone!

5. The unit seems sprung loaded to the base of the tank, when you undo the collar it will spring up. Don't take it out yet...

a. If you have not put gloves on - do it now - you will get diesel on your hands

b. Get a drain pan - when you take the unit out, it will be full of fuel - about 1/2 a litre - and will not easily tip back into the hole.

c. When you pull it out be careful not to bend the float rod - it sticks out a good 6"

6. When the unit comes out, drain it and admire all the diesel muck. The unit is actually white, mine was black - so black the 'filter' at the bottom was caked full! It took me 15 minutes to clean it!

7. 'Luckily' for me it was the broken solder joint detailed in the previous post - easily tested and easily fixed.

8. I did not replace the seal that holds the unit in place - you might want to buy one before you start - I didn't think to buy one and may well regret it.

9. When I replaced the unit, I pushed it into the hole. I then reseated the seal and pushed the unit down into place - lining up the lug on the 'right'. If you are struggling to hold it in place because it seems to be springing out then you have probably not seated the seal properly.

10. You will be able to start the collar onto the thread by hand - but you will need that special tool again to do it up.

11. If I anticpated doing this more often - or I had to do this job in a rush, I might contemplate cutting a hole in the carpet! The 'carpet' actually about an inch thick - so it would make a half decent repluggable hole. If I were to do this the hole would need to be 30cm square, on the middle line of the car 33cm from the back edge of the carpet. There is a little leeway in the measurements - but your mileage may vary.

As I type, I've not replaced the carpet, panels and seats but I don't see that as being too long a job - I reckon, all in, it will have taken about 6 hours - you might well be able to do it a lot quicker.
 
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Or you could cut down the middle of the boot carpet with a sharp Stanley knife, fold the two halves open and retain with gaffa tape.

That gives you access with about 2 mins.

When you finish, unfold the two halves of the carpet ensuring you get a good join before flattening everything back down and it's nigh-on invisible.

Sounds drastic perhaps but actually works really well.

Dave
 
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