Fuel Guage problem

[AudiSport]

I have a 1998 (S) Audi cab and the fuel guage is all over the place. Most of the time it just sits on 1/4 of a tank - however this morning it had decided to display half a tank of fuel - oh and the fuel low light also was on...

What is faulty, the guage or the tank... Eeek!


? ? ?

Thanks guys!

[4rings]

My 98 cab decides its self what it wants to show:aargh4: majority of the time its bugger all, but if I fill her right up she'll show 3/4 full, I can never rely on it I use the trip to judge how much fuel I've got in it I work it out at roughly £20 gives me 125 miles, don't know if thats good or bad but I do tend to sit heavy on the right pedal:Blush2: .

If anyone knows the answer to the crappy fuel guage problem I'm all ears.

Tony

[BarryD]

Hi same problem here. My 99 cab has dippy fuel and temp gauges. They tend to read what they want to. I fill up around 280 miles and she will do 350 to the tank at a pinch.

I replaced the temp sensor but to no avail. Someone said it was a common data bus error and likely to be unsolvable without load of mony being spent.

If there is a solution - please share :)

[AudiSport]

I've done some searching around on a few forums and I see a lot of people mentioning the 'fuel level sending unit' which is located in the top of the fuel tank. See link.

http://www.audifans.net/modules.php?name=Forums&file=viewtopic&t=17321

About £67 for the part from Audi... and £20 mates labour rates to a local mechanic.. What do you think, shall I throw £100 at the problem.. Or is it something eles. Maybe I'm best spending £85 at Audi and have them diagnose the exact problem..

Hmmmmm!

[onzarob]

have a look here may explain it.

http://www.bba-reman.com/content.aspx?content=audi_a4_dashboard_cluster_fai ling

get the fault codes read or try VAG-com out with a cable for £30.

www.ross-tech.com (http://www.ross-tech.com)

cable from here www.gendan.com (http://www.gendan.com)

Rob:D

[a8 tech]

Checking dash panel insert components
Checking and adjusting fuel gauge
Open convertible top compartment.Unfasten convertible top compartment lining at rear and fold it forwards.
Use screwdriver to prise off cap.
Unplug connector from fuel gauge sender.Connect up multimeter for voltage measurement between contacts 1 and 2 of connector. Switch on ignition. YOU SHOULD HAVE 10 VOLTS.
Switch off ignition.
If reading does not match specification, use current flow diagram
to locate and eliminate open circuit in wiring/check voltage stabilizer
Connect up tester V.A.G 1301 between contacts 1 and 2 of connector
When connecting, take care not to push back receptacles in connector.

Set tester V.A.G 1301 as follows: (RESISTANCE TESTER THAT ALLOWS YOU TO SET THE VALUES OF FULL AND EMPTY)

Switch on ignition for at least 2 minutes.
Pointer of indicator must be on right edge of third red bar
Tap gently with finger on glass of dash panel insert whilst taking reading.
If reading does not match specification, use pointed noise pliers to carefully pull off cap for adjusting screw.
Cover glass of dash panel insert with cloth to avoid scratches Set pointer to specification by turning adjusting screw -A- with Allen key/screwdriver.
Tap gently with finger on glass of dash panel insert whilst making adjustment.
Engine is not to be started.
Replace indicator if reading still does not match specification.

[AudiSport]

so, you think it is the dash that is at fault, and not the 'fuel sender' in the tank?

It would be cheaper to get Audi to find the fault than shed out on all the VAG.com kit+ PC (I have a mac)..

Unless anyone in the Dorset area has a copy I could plug myself into for a few drinks!!

[AudiSport]

Checking dash panel insert components
Checking and adjusting fuel gauge
file:///c:/elsawin/data/tmp/mobile/graphics/wi/V90-0871.png<LI class=nonenone>? Open convertible top compartment. <LI class=nonenone>? Unfasten convertible top compartment lining at rear and fold it forwards.
? ? Use screwdriver to prise off cap.
file:///c:/elsawin/data/tmp/mobile/graphics/wi/V90-0872.png<LI class=nonenone>? ? Unplug connector from fuel gauge sender. <LI class=nonenone>? Connect up multimeter for voltage measurement between contacts 1 and 2 of connector. <LI class=nonenone>? Switch on ignition.
? Specification: 9.8 ... 10.4 V<LI class=nonenone>? Switch off ignition.
? If reading does not match specification, use current flow diagram
to locate and eliminate open circuit in wiring/check voltage stabilizer => Page 90-21 (http://www.vwaudiforum.co.uk/forum/vw-wi://ctrl:idref=idazgaef/). file:///c:/elsawin/data/tmp/mobile/graphics/wi/V90-1031.png
? ? Connect up tester V.A.G 1301 between contacts 1 and 2 of connector.Note:
When connecting, take care not to push back receptacles in connector.

<LI class=nonenone>? Set tester V.A.G 1301 as follows:
? 280
? Switch on ignition for at least 2 minutes. file:///c:/elsawin/data/tmp/mobile/graphics/wi/V90-1096.png
? ? Pointer of indicator must be on right edge of third red bar (reserve) -arrow-
Tap gently with finger on glass of dash panel insert whilst taking reading.
? If reading does not match specification, use pointed noise pliers to carefully pull off cap for adjusting screw.Note:
Cover glass of dash panel insert with cloth to avoid scratches.
file:///c:/elsawin/data/tmp/mobile/graphics/wi/V90-1096.png
? ? Set pointer to specification by turning adjusting screw -A- with Allen key/screwdriver.Notes:
<LI class=nonenone>? Tap gently with finger on glass of dash panel insert whilst making adjustment.
? Engine is not to be started.
? Replace indicator if reading still does not match specification.

I'm lost, sorry... Please explain?

[a8 tech]

Your model is 98 cab then the instructions are telling you how to test the gauge.I would advise you get it looked at as you will need to test the resitance values of the tank sender and compare to actual reading at the dash.Sorry not trying to confuse you.I have edited the instructions for checking the gauge,hope that is a bit easier to take in.The fuel sender unit is more likely but consider the test of the wiring to the gauge and the gauge itself.Vag com will be of little use as this will require good old electrical testing.You could take the sender out of the tank and move it slowly from empty to full and watch the gauge.also test for resistance change with a mulitimeter when moving the sender arm,any big jumps or lack of change will also give you some idea as to the state of the sender.If i have over complicated the discription tell me i wont bite.Best Regards Jon

[a8 tech]

Have another look :Blush: