Fuel Sender Unit can anyone help?

[ChrisO GolfO]

Right just been out in the freezing cold,

Got the sender unit out of the fuel tank this afternoon. Looked at it all over, and checked it looks okay there is no punctures in float. I have been reading some threads on the forum using search function but nothing that really helps. Closest I got to anything was shorting two wire purple n black and the brown one. Have tried this with some wire but unsure if i had a good conection or if I was doing it right. Can anyone help. Bright side is the car has almost full tank of fuel!! 

Cheers
Chris

[herbster]

I got a sender unit in my garage if all else fails! Have you checked it with a ohmeter and voltmeter? Check for voltage off the wiring,  remember the ignition has to be on!    do one terminal at a time with neg to earth, there should be something on the meter. Take the sender out try the ohmeter on terminals hold them on and move the float up and down, the ohmeter reads 0.000 when its a full tank, >0.001 when its below full, the float moving changes the readings if it works right. Its a bit like a dimmer switch in the house on the lights controlled by the fuel level. Good luck, hope you understand what I mean!!! 
 

[rubjonny]

you need to bridge pin 1 & pin 2 on the level sender plug, this shouls make the fuel gauge shoot to max.  If not the wiring or clocks are shot!
To check if its the wiring, get behind the fusebox and disconnect plug M, then with the bridging wire in the lift pump plug still connected check across pin 3 & 6 for continuity (vio/blk & blk/brn wire)

Check my fusebox FAQ for more info, to drop the fusebox 1st remove the dash under tray, then pop off the 2 white clips either side of the fusebox.  Push the left side of the fusebox hanger to the left to disengage the locking tab then lift it up and pull towards you.  To disconnect the fusebox plug you 1st have to pup the locking tab on the back of the fusebox across.

P.S. its very important that all the nuts/bolts on the rear of the fusebox are done up tight, and you'll notice the nuts are behind the temp & fuel gauges, not only do they hold the gauges in but they also provide the electrical contacts, so make sure there are no fibre washers or anything like that on them!
Good luck!

[ChrisO GolfO]

I got a sender unit in my garage if all else fails! Have you checked it with a ohmeter and voltmeter? Check for voltage off the wiring,  remember the ignition has to be on!    do one terminal at a time with neg to earth, there should be something on the meter. Take the sender out try the ohmeter on terminals hold them on and move the float up and down, the ohmeter reads 0.000 when its a full tank, >0.001 when its below full, the float moving changes the readings if it works right. Its a bit like a dimmer switch in the house on the lights controlled by the fuel level. Good luck, hope you understand what I mean!!! 
 

Tried this today as I was measuring with the multimeter the readings kept cutting out like it was not making a good connection, kept jumping between 100 odd and OC which means dead connection. I think it could be screwed.

you need to bridge pin 1 & pin 2 on the level sender plug, this shouls make the fuel gauge shoot to max.  If not the wiring or clocks are shot!
To check if its the wiring, get behind the fusebox and disconnect plug M, then with the bridging wire in the lift pump plug still connected check across pin 3 & 6 for continuity (vio/blk & blk/brn wire)

Check my fusebox FAQ for more info, to drop the fusebox 1st remove the dash under tray, then pop off the 2 white clips either side of the fusebox.  Push the left side of the fusebox hanger to the left to disengage the locking tab then lift it up and pull towards you.  To disconnect the fusebox plug you 1st have to pup the locking tab on the back of the fusebox across.

P.S. its very important that all the nuts/bolts on the rear of the fusebox are done up tight, and you'll notice the nuts are behind the temp & fuel gauges, not only do they hold the gauges in but they also provide the electrical contacts, so make sure there are no fibre washers or anything like that on them!
Good luck!

Tried bridging pins vio/blk and a thick brown wire nothing on fuel guage, the pins go something like brown, colour, blk/vio and then i think yellow and something. If i follow the wire back something leads off it to a white connection which has a simple red and black wiring kinda home made so to speak could this be causing head aches? Had to come in as it was bloody freezing.

Have yet to test fuse box but if all else fails do you think a qualified sparky could do it? I have about 100 pounds cash hey its up for grabs if you can solve it!!!   

[rubjonny]

doesnt sound right to me?

[ChrisO GolfO]

I will check it out and take some proper decent pics of the wiring on the weekend then we can all see what it looks like, will be too dark when i get in tonight. Hopefully be able to get to the bottom of it all but I know it deffo shouldnt be jummping arround on readings like that.