Re: Why a computer in cluster (was: Gremlins in Tank)

[SMILLER@xxxxxxxxxxxxxx]

John, that is interesting, educated speculation, and sounds plausible.  So
if fuel gauge circuits need to be so complicated now, for the reasons
you mention, I'm just curious:  Do other makes of cars have similar
circuits and problems?

Scott Miller
GGC BMW CCA #44977

>Date: Wed, 23 Sep 1998 21:47:05 +0200 (MEST)
>From: John Firestone <john.firestone@domain.elided>
>Subject: Why a computer in cluster (was: Gremlins in Tank)
>
>Scott Miller writes:
>> 
>> New BMW gas gauge:  Sender in tank, wires to computer, wires from
>> computer, gauge in dash.
>> 
>> Question:  Why does the gas gauge need a computer?
>
>Several reasons I expect:
>
>   - to detect faults in the fuel sender signal (shorts to ground, to +12,
>     intermittent connections, faulty senders and nonsensical readings);
>
>   - to pinpoint problems with the fuel gauge via the cluster system test;
>
>   - to monitor the fuel senders via the workshop DIS computer;
>
>   - to simplify the low fuel warning and make it more repeatable;
>
>   - to simplify the OBC and insure its displayed RANGE is consistent
>     with the instrument cluster;
>
>   - to allow easy, software downloads to the cluster (coding data) that 
>     adjust for differences among models or changes over different 
>     model years (e.g. a different tank size).
>
>- -John
>'96 318is
>john.firestone@domain.elided

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