[urq] Fuel gauge reads 3/4 when tank full

[Chris]

My urq has had the exact same problem since I bought it. 
> On Sep 12, 2016, at 15:27, Frank de Kat <fdekat at sentex.net> wrote:
> 
> From this link, it appears the sender is a separate part.
> 
> http://audi.7zap.com/en/usa/audi+quattro/quat/1985-46/9/919-101005/
> 
> Usually, you have to 'undo' a ring that clamps the sneder into the tank, then carefully remove it through  the opening..  And not sure if the tank has to be out to get it out the opening in the top..
> 
> =Frank=
> 
> 
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>>   1. Fuel gauge reads 3/4 when tank full (Alan Pemberton)
>> 
>> 
>> ----------------------------------------------------------------------
>> 
>> Message: 1
>> Date: Sun, 11 Sep 2016 17:08:22 -0700
>> From: "Alan Pemberton" <alan_pemberton at telus.net>
>> To: <urq at audifans.com>
>> Subject: [urq] Fuel gauge reads 3/4 when tank full
>> Message-ID: <003a01d20c89$c734b9e0$559e2da0$@telus.net>
>> Content-Type: text/plain;    charset="us-ascii"
>> 
>> This problem was noticed when I had the car filled up and only reached 3/4
>> of a tank.  I couldn't be certain that the tank had been completely filled
>> so, yesterday, had it filled up completely but the gauge does not go above
>> 3/4 tank.
>> 
>> 
>> 
>> I thought at first that I had a problem that hadn't come up on the list but
>> not the case!  10 years ago Louis-Alain had the same problem and provided
>> the relationship between sender resistance and fuel level (see below).  My
>> tank, completely full, reads 63 Ohms so the issue must be the sender.
>> 
>> 
>> 
>> There are some comments in the email thread started by Louis-Alain noting
>> that the orientation of the sender in the tank must be correct.  The sender,
>> as far as I know, was never removed before I purchased the car in 1993 and
>> has not been touched since.
>> 
>> 
>> 
>> In the Audi system, the sender appears to be part of the fuel tank and not
>> available separately.  Does anyone know the cause of this issue and if it is
>> fixable?
>> 
>> 
>> 
>> Alan
>> 
>> 1985 urq
>> 
>> 
>> 
>> -----Original Message-----
>> 
>> From: urq-bounces at audifans.com [mailto:urq-bounces at audifans.com] On Behalf
>> Of Louis-Alain Richard
>> 
>> Sent: October-11-06 12:44 PM
>> 
>> To: urq at audifans.com
>> 
>> Subject: [urq] Mine will not read full : anyone have a fuel guage?
>> 
>> 
>> 
>> Addendum to my own post:
>> 
>> 
>> 
>> The resistance values of the VAG1301 are not true ohms values, as per this
>> page (look at the bottom for a chart)
>> www.bentleypublishers.com/tech/vw/bentley.vw1301.testing.htm?ticket=none
>> 
>> 
>> 
>> I've plotted the data from this page to obtain a graph of the relationship
>> between VAG1301 and real values.
>> 
>> 
>> 
>> Hence, to test the fuel gauge circuit, you must use these real ohms values
>> 
>> :
>> 
>> 
>> 
>>                                Real value                           VAG1301
>> values
>> 
>> Full tank               39 ohms                               60
>> 
>> Half tank              88 ohms                               155
>> 
>> Reserve               159 ohms                             302
>> 
>> 
>> 
>> It all makes sense, because I've already tried the VAG1301 values and my
>> fuel gauge wasn't even near the corresponding marks. So all you need is a
>> 
>> 40 ohms resistance and place it between the 2 wires at the sending unit and
>> your gauge should read FULL. If yes, replace the sending unit, if not check
>> elsewhere. Mine works beautifully.
>> 
>> 
>> 
>> Louis-Alain
>> 
>> 
>> 
>> 
>> 
>> 
>>> > -----Message d'origine-----
>> 
>> 
>>> > And if you don't have a Bentley, you can look at these scans of the
>> 
>>> > official WR shop manual...
>> 
>>> >
>> 
>>> > http://www.wrquattro.com/info_data.html
>> 
>>> >
>> 
>>> > Fuel gauge testing is at page 127
>> 
>>> > (http://www.wrquattro.com/QuattroManual/QuattroManual131.jpg)
>> 
>>> > and IC voltage regulator at page 126
>> 
>>> > (http://www.wrquattro.com/QuattroManual/QuattroManual130.jpg).
>> 
>>> >
>> 
>>> > Louis-Alain
>> 
>> 
>> 
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