Help! Fuel tank wiring...

Hi

Had a new crossmember fitted recently - fuel gauge hasn't worked since.

Haven't had a chance to take it back to garage yet but was poking around to find the problem.

Might have found the culprit - there's a random wire / plug hanging loose but I can't find anywhere for it to plug into.

There's a black wire and a white wire with purple or black thin stripe going into the loose plug. Might be a black stripe that's faded.

The fuel sender has a green wire and black wire going to it.

Some photos below - any ideas?! I'm confused!



Cheers

What engine is it - TD5 perhaps??

Daz

Ah, sorry - 300tdi. 1997 if that makes a difference.

It should really just be the two wires that already connected. Have you tried taking them off and giving them a clean?

Is it a 110 with a rear tank??

Daz
(a bit of info might help diagnose it mate)

Right - it looks like its a rear mounted 110 tank

The plug should plug into the fuel gauge sender on the right hand side of the sender opposite the fuel line

Daz

Oh... That was the first thing I tried but couldn't get it to fit. Could it be that there's a part that's fallen off that would connect the two. The right hand part of the fuel sender doesn't look like it has holes to recieve the three pins on the plug? Will go and try again...

Yep, it's a rear mounted tank - 1997 110 300tdi.

The circular part of the sender on the right is where the plug goes

(got there in the end )
Daz

Right, thankfully I'm not being entirely dumb! Just tried again - it does look like it should connect there but the plug and that socket definitely won't go together.

The plug has pins and two moulded lumps inside to fit into whatever female connector it's designed for.



The socket on the sender has a centre hole that gets in the way of the pins on the plug. Pretty sure they're the same diameter too - so the plug can't fit over the socket.



Could it be that there was a connector between them that's fallen off?

Could be (i haven't got a 110 - so can't go and check)
Hopefully someone with a 110 will go and pull their plug off and have a look.

Hope you get it sorted

Daz

Thanks anyway, appreciate it.

It's the same as my mates and I'm positive that his has a blank plug the same as yours. No idea what that spare cable is but the two wires in the middle are definitely connected to the gauge. If you take out the float you'll see how it works, its pretty simple

MMMMM that makes sense as there are only 2 pins in the plug - on your pic whats on the end of the 2 wires coming from the sender - the plug socket maybe???

Daz

Nope, the two wires go into a plastic junction (eg two sockets that snap together). The two black wires from the sender come out of the junction as a green and black wire and...

...the wire from the mystery plug leads off in the same direction. All three wires are bound together in heat shrink or electrical tape, or something, and lead off out of reach.

I read elsewhere that the green cable does the fuel empty light, the white is the gauge and black is earth. By this logic, assuming its right, seems like the gauge and empty-light have separate earths. And the gauge is currently disconnected.

But how to connect it?!

The sender is basically a plastic ball which is connected with a stiff metal wire. When the level of fuel changes a small metal 'brush' at the end of the wire changes position on a small circuit board like thing thus transmitting the level to the gauge. My 90 only has two wires on the sender. It could even be something as simple as they are on opposite way round. Try taking them off to double check. I assume you don't have a haynes manual to hand? Mines is in the car unfortunately

You could bridge the pins with a piece of wire and check what registers on the fuel gauge

Daz

Thanks chaps - I'll have a prod around tomorrow and see what happens.

will try to remember to have a nosey at mine before it gets dark when I finish work...

Hungrydave said:

Hi

Had a new crossmember fitted recently - fuel gauge hasn't worked since.

Haven't had a chance to take it back to garage yet but was poking around to find the problem.

Might have found the culprit - there's a random wire / plug hanging loose but I can't find anywhere for it to plug into.

There's a black wire and a white wire with purple or black thin stripe going into the loose plug. Might be a black stripe that's faded.

The fuel sender has a green wire and black wire going to it.

Some photos below - any ideas?! I'm confused!

View attachment 36881View attachment 36882

Cheers

Click to expand...

That plug you see is for an in tank fuel pump not the sender, the black wire and a green wire that plug into the fuel level sender look fine. - could be loose or broken... check where the loom comes upto the bulkhead.