Fuel gauge issues | advice needed asap |

[Foz]

So i'm trying to tackle my fuel gauge issues once again
I Replaced the fuel sender...still not working
Tested my fuel gauge by earthing the white wire (there are 2 wires out of the back of the gauge 1 white, 1 brown) straight to the body and it shoots to full, so i presume my gauge is fine?

So i ran a length of wire straight from the Sender terminal to the white wire and again gauge shoots to full, tried it to the brown wire and i get sparks.

i know my tank is approx half to a quarter full, yet every connection i try it shoots the gauge straight to full.....what am i doing wrong?...or what do i need to do, to establish the correct connection. and make the sender work correctly?

i'm no mechanic or electrician, so idiot proof directions/advice would be handy

I have an electrical tester, but not quite sure what or how to test with certain knowledge.....i did however test the brown wire out the back of the gauge and a reading of approx 10.47volts comes up....tested the wire at the sender end and i get nothing at all, am i supposed to get a reading at that end?

help please :?

 

[StuF]

Think the measurements should be taken in OHMS mate rather than volts

Have a look here at Speedy Jims Site

http://www.speedyjim.net/htm/fuel_ga.htm" onclick="window.open(this.href);return false;

As we have both said before - maybe someone working on your bus in the past has severed the sender wire somewhere and it might be a case of tracing that down and repairing it!

Sorry I cant be more help

 

[StuF]

Some more testing pulled from the interweb

The first test is to turn on the ignition, and remove the wire from the fuel tank. With the wire to the tank disconnected the gas gauge should read empty. Now ground the wire, and the gas gauge should read full. If it reads empty with the wire off and full with the wire grounded, the gauge and it’s wiring should be good. To go any farther you need an ohmmeter. You can get a simple one for $5 at harbor freight tools. The fuel tank needs to be grounded for the gas gauge to work on your VW. Set the ohmmeter to X-1 and put one probe on the tank right next to where the wire goes on, and ground the other probe. If the tank has a good ground then the meter should readjust a few ohms. If the reading is zero, then the tank is not grounded and the gauge cant work. Most VW tanks ground from contact with the chassis. Some have a brown ground wire near the wire from the gas gauge. Either way if the ground is bad, you need to establish a good ground.

From there you can use the ohmmeter to check the sending unit. Ground one probe to the tank right next to where the fuel gauge wire attaches. If the sending unit is good it will read 75 ohms when the tank is empty, 1/2 tank should read about 37 ohms, and 10 ohms when the tank is full.

These steps will allow you to accurately check out the gauge/wiring, the sending unit, and the ground, so you will know precisely what is wrong, without tearing it all apart. If you have any more questions I am here to help. Good luck

 

[Foz]

Is that the correct setting to read ohms?

--------------------------------------Own a Bay?....... Feel the love!

 

[Foz]

Right I connected to the terminals of the sender and got this reading, which is about right for half a tanks worth....correct?

So my senders working.....my gauge is working it seems......just not together. Or am I missing something basic here? If I run a trmporary feed from the sender to the gauge, surely it should work? Yet it shoots to full :evil:

--------------------------------------Own a Bay?....... Feel the love!

 

[StuF]

Both look to be working fine and the ohms setting is the correct one.
Make sure your gauge and sender are both connected to earth/bare metal

Will try and dig out the wiring diagram

 

[StuF]

Here is the wiring diagram - Simples! :shock:

 

[Foz]

cheers for that stu :lol:

head completely blown now :msn4:

managed to reconnect a temporary feed from the gauge to the sender and got a reading of half......finally!!
So now I've established there is a break in the wire between the sender and the gauge! oh lummy!! :|

Going to be fun trying tp find the correct wire....AND find the breakage, if not run a completely new wire! :roll:

thanks for your help Stu..... 8)

 

[StuF]

The break could possible be around the area you may have had some rear suspension work done

Maybe a quick look around there where the wire comes from the sender in the tank and through to the outside might be worth a quick investigation

Atleast you have a working gauge and sender! :lol:

 

[Foz]

Found it!

Fixed it!

Yay!...a working fuel gauge! :mrgreen:

--------------------------------------Own a Bay?....... Feel the love!

 

[StuF]

Awesome news mate - you must be well happy now! 8)

 

[Foz]

Chuffed Yeh, tho I cant put the dash back fully yet as I gotta replace the speedo cable. Took a look underneath and its snapped about 10cm out from the wheel hub. Ordering it from JK this weekend, so thats next weekends job.....after that....its propex time!! Not looking forward to that job!

Your fuel gauge is safe mate, I'll bring it back to Spa with me in Aug. unless you want me to post it back beforehand?

--------------------------------------Own a Bay?....... Feel the love!

 

[mike202]

great result, lucky that the break was visible!

 

[martin.sim]

Good job well done


--------------------------------------
Why didn't I buy my bus years ago !?

 

[Whistler]

Hopefully someone can help. Not the same as Foz as I have a brand new loom. When shorting the wires the gauge goes to full. When I turn the ignition on the gauge goes to R but when I follow the pictures to test the ohms the meter stays at one. Is there anything wrong with that? I was expecting it to go to 75ish as the tank is bone dry.

 

[Mikesocal]

I have a 71 Westy and have played with the fuel gauge now a few times without any luck. While the motor was out to be rebuilt, I decided to replace the sending unit in the tank because the original one would stick often. I also used Por 15 in the tank and replaced the fuel filler hose etc. I did not think to test the sending unit before installing it which I should have (Motor is all back in now). With the key off the gauge reads Empty and when I ground it out it shoots to Full. No matter how much fuel is in the tank it reads just a little past Half. I tried running a new ground wire from the rear of the instrument panel to the chassis but that didn't make any difference. The tank itself has a ground wire going from a bolt on the sending unit (that goes into tank) to the roof of the tank compartment and the brown wire comes down below. Since I can't get to the tank I spliced the brown wire that exits the tank area and ran a new wire temporarily to the gauge and get the same result. Just a little more than half full. I am considering buying a new gauge itself unless you guys have any other suggestions? Could I possibly buy a cheap fuel gauge at my local auto parts store and connect it under the rear to see if it works differently before buying a new VW one and tearing out the instrument cluster?

Thanks!

 

[chad]

My brand new sender was faulty which we didn't realise until the engine was back in.

 

[Webbaldo]

I know this thread is ancient but I gave up with the OHM tests.

Real world simple test below

Just bought a new sender, connected with battery/ignition on.

Turned sender (slowly) up and down a few times, noted the gauge moved and hey presto works.

Sadly unless you have no engine in, or an access panel like some US vans that's really the only way you can do this method.

Engines easy enough to take out. I used to be scared but it really is easy on an EB

Crossover/Late yes a pain with rear crossmember.