RE: Restored top bar in RID fuel gauge

["Clive Liddell" <cliddell@xxxxxxxxxx>]

Hi Soren,
Interesting.   The Mercedes fuel level gauge also runs from ~3.3 to 85.5
Ohms.  The usual "complaint" on these is needle flickering usually at 1/4
tank and below.  Needless to say I've cleaned my potentiometer and it's
needing it again but...  my thoughts on this are a little different than you
found:

My theory is that at the higher resistance (tank emptier) the current
through the sliding contact(s) is reduced and thus has less "burning" or
self cleaning effect on that portion of the pot. allowing deposits to build
up. (I always run from Full to Reserve on all my vehicles so all portions of
the pot. would be used).

Now thinking about the BMW "top bars":  If the contact to potentiometer is
bad at the top would that not cause intermittent display unless the added
resistance is very stable?  Are there no additional connectors in the tank
that may have been reseated at the same time?

The above is just a discussion topic since you have the proof of the
pudding - that yours is now working perfectly.

BTW is there a new O-ring needed when R&R the gauge sender?

Thanks again.
Regards
Clive Liddell
Pietermaritzburg, South Africa
'96 R850R ~77kkm
'01 R1100RT ~57kkm

> -----Original Message-----
> From: owner-oilheads@xxxxxxxxx [mailto:owner-oilheads@xxxxxxxxx]On
> Behalf Of Soren S. Jorvang
> Sent: 04 May, 2005 16:45
> To: oilheads@xxxxxxxxx
> Subject: Restored top bar in RID fuel gauge
>
>
> Hi.
>
> Since I had the tank open to replace the fuel filter anyway, I
> decided to see if I could make the fuel gauge show all the way full
> rather than missing the top one or two bars. I had previously tried
> cleaning the wiring connectors for the tank and RID with no effect.
>
> The potentiometer had a thin layer of black smudge mostly over the
> upper part of the range (VDO in their wisdom made a full tank read
> as little as 3 ohms :-/ ).
>
> I gently wiped the potentiometer down with brake cleaner and now the
> RID fuel gauge works like it is supposed to!
>
>
> --
> Soren

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End of oilheads-digest V2 #107
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