OK, where next?
 

Fuel gauge reads full until last few miles when it drops to half way, then you're out of juice.

Replaced BOTH senders in the fuel tank with much stinking diesel pouring out.
Absolutely no difference. Then I discover this ebay posting:

http://www.ebay.co.uk/itm/VOLVO-850-...item3371d9593b

When I had the main pump out, I noticed this white thing sticking into the tank. Why, in the name of reason would we have THREE senders?

Or is this a blind alley? Is there a calibration to carry out?

Do enlighten me.... please!

If you have a VOLVO 850 S70 V70 1993-2000, then this will be the fuel sender you need, but as you have posted in this forum, then you have 2000 -2007 car which this wont fit.

Have you tried testing the gauge by earthing the sender to see if the needle goes up or down?

Which sender does the main sensing? As my fuel gauge remains full on until the fuel is almost gone I assume one of them gives most coverage then the other does the last bit. The lowest point seems to be the sender without the pump unit. So I presume this is the 'last bit' sensor. Am I right?

Joe , whats the model V70 D5 ? Had a look at your profile but you have not mentioned what car it is .

V70 2003 D5 series 2.

I will take a little time this weekend to check the float readout resistances, they vary between 0 (full position) and 330 Ohm (empty). It might be I have a float jammed in when refitting it.
The other possibility which I am leaning towards is a diesel-proof gremlin who lives in my fuel tank and simply holds the float up.

Mine is a 2003 V70 D5 also , I have given myself a similar problem . I replaced the in tank pump but instead of removing the second sender and cross feed pipe I left the old one in the tank and plugged the second sender into the underside of the new pump housing top plate . I know this was a bodge but I was under pressure as the car had more or less broke down and I had a limited time to get moving again . My tank is now showing almost into the red when its actually empty due to one of the floats fouling I think . As far as I know there are only two senders not three . The car takes an average of the two senders , I dont know what the ebay thing is but I cannot see one in my tank but I am also convinced my car has a gremlin in the tank which keeps making the fuel pump fail . There is no calibration you can do . You are checking that the arrow on the top of the senders/pump is pointing to the rear of the car ?

did you make sure on the nearside sender the tubing/pickup is clipped to the bottom of the sender(there is an obvious clip if you look). otherwise it will show half a tank as the tubing wont allow the float to move. i struggled with this until i clipped it back on. Also make sure the arrows are facing back

The thick plottens
 

Checked float resistances in situ. Nearly empty = 140 ohm. Full tank less than 50. Clearly this part is working. Shake the car and the resistances change slightly. Disconnect the far sender (without the pump) and after a few moments meter drops to zero.
Checked plug connector, all okay. Is it possible there is a break in the connectivity to the meter somewhere?

Getting bored with the whole thing, glad it's not vital.

Did you try to do anything to speedo??
Once spring is bent showing similar problems.

Done nothing to that end of car and won't unless I have to. On reflection I think we have a poor connection on one of the three wires that connects to the two float switches. Where it might be, I don't know. If I could get a Volvo dealer to quote me a fixed price....