100TQW MAC14 MC-2 won't start

[isham-research.freeserve.co.uk at pop.pol.net.uk]

>> From: quk at isham-research.freeserve.co.uk
>> Then I switched the battery back, and the REAL problems
>> started.  The car won't start (no spark) and the ECU
>> cnsistently stores 'coolant sensor'.  Also the tachometer
>> jumps to 3500 revs as soon as the key is turned.

> Might not be related, but . . .

> I saw these symptoms once on a VW that I'd stored for a couple of years.
> Turned out to be a 12V battery with a couple of dead cells.  Completely
> confused the tacho (read half scale all the time), indicator relay etc.  I
> wouldn't think the computer would be too keen on low volts either!

I've seen very odd behaviour in ur-quattros with failing alternators -
persistent ABS and brake pressure warnings, for instance.  So that was
my first port of call and the original reason I swapped the batteries.

The batteries are identical - both Audi parts - and mine has written
on it: "Changed at 97k miles, 27 Jan 1999".  I'd like to think it
hasn't failed yet, but I'm keeping an open mind for the present.

--
 Phil Payne
 UK Audi quattro Owners Club
 Phone +44 7785 302803   Fax: +44 7785 309674