Fuel sender broken?

[spandit]

My fuel gauge wasn't working when I picked up the Pinz, but I knew with a full tank I'd get home OK, which I did!

I shorted the purple sender wire to earth and the gauge reads full, which implies to me the gauge is working fine (using a slightly dodgy earth gives a less than full reading, which is good).

Taking the sender out, I can hear that the float moves up and down fine - removing the end cap shows that this is the case but I'm only getting mega high resistance whatever the float position (more or less open circuit) so not all well. Is there a sliding contact that can be repaired inside the sender or do I have to get a new one, in which case, can I have the partnumber, please?

[pcolette]

I'll be interested to see what replies are posted since I am having the same problem. I have a new VDO gauge with all new wiring but always shows empty.

The sender part number is 7111670250.

Paul

[lindenengineering]

Guys
First remove the sender from the tank, (its exposed by taking off the bed plate/cover.)
With it laid on the bed, re-connect the sender wire, ground down the top plate with a temporary length of wire connected to the ground spade terminal, then turn on the ign.
Gently tip the sender assy up and down listening for the internal float to slide inside the tub. If eveything is connected PROPERLY at the sender AND under the dash it will register a change at the guage if working correctly.
Dennis

[pcolette]

Thanks Dennis.
That's what I tried yesterday but with an ohmmeter connected to the sender rather than the gauge. It showed a completely open reading and no change as I tilted the sender. The float was moving freely inside the tube.

I suppose I need a new sender.

Paul

[spandit]

Dennis,

Same here, I get a 6.5MΩ reading between the terminal and the body of the gauge, regardless of the float position. Taking the bottom plate off the gauge shows the thick wire (presume the resistive wire) and a very thin wire running up both sides - a guide wire? Not sure what would happen were I to undo the small nut exposed by taking the plate off. I've seen these senders for sale for £300 ($500) in the UK which seems extreme.

The gauge wire was connected to terminal 2 on the sender, which doesn't have a part number stamped on it, apart from "77"

[lindenengineering]

From what you two blokes are stating it looks like they are both shot!
Yes spendy parts for sure.
I don't have any used ones at present, they go like hot cakes if I get a wreck in to break up!

I will keep you two in mind if some come my way.
Dennis

[spandit]

The sender in mine is 330mm long but the tank is 450mm deep at that point, so thinking I could fit a longer sender, either 9 or 10 off this site (UK):

https://www.europaspares.com/INSTRUMENT ... _5017.html

I know the resistance might not be correct, but if it gave me any indication on the gauge it would be better than nothing and I could always stick some calibration marks on it.

Still not sure why mine isn't working as everything seems OK inside the sender. Have reassembled it so prevent crap falling into the tank, and added a better earth, so I can always hope it will magically start working again!

[edzz]

Or shorter for an increased reserve. Good parts find.

Ed

[spandit]

I'm a tightwad so don't like spending money unnecessarily! Next job is to find a cheap way of fitting disc brakes!

[edzz]

I'm a tightwad so don't like spending money unnecessarily! Next job is to find a cheap way of fitting disc brakes!

Be cheap stay with drums like most of us.

Ed

[pcolette]

I was able to source the sending unit from SAV today for $125.00. The part number is 7111670250 and can be viewed here:

http://www.pinzgauer.com/showdetails.ph ... 111670250/

I wasn't able to find the same part on EI's website but Scott may have it also.

Paul

[spandit]

Thinking I had nothing to lose by breaking my existing sender even further, I took it apart.

First, undo the small (5.5mm) nut at the bottom of the sender tube, then you can remove the end cap and brass locking washer.

Next, wearing gloves so you don't get cut by the terminals, grasp and twist the top which is only press fitted onto the tube. With the tube removed, the innards are exposed.

Running up the centre of the assembly is a metal rod - this is the guide for the float and should be earthed.

There are then 3 wires, 1 thick - this is the signal wire for the "idiot" light, which is switched by a brass disc on the float shorting 2 terminals on the base (connects directly to the spare terminal on the top), and 2 very fine wires (which is actually one wire looped round). These fine wires are nichrome (I presume) and are what gives the sender it's variable resistance as the float moves up and down (there are sliding contacts between the wires built into the float). One end of the wires is connected to the sender wire terminal and the other, although it doesn't look like it, is connected to earth.

What was wrong with mine is that firstly, the aforementioned earth connection wasn't working and secondly, there was open circuit between the terminal and the other side, which was fixed by moving the terminal with some pliers to break the corrosion.

On the bench, I was reading about 6Ω at full position and 95Ω at reserve. I couldn't get the gauge to really do much but when I bolted everything back in again (using new stainless fasteners with copperslip) it gave me an intermediate reading so hopefully I'll get some indication of when I'm about to run out of fuel. Have just bought a jerry can which I'll take with me as spare