[urq] sudden stumbling (RESOLVED!)

urq urq at pacbell.net
Sat Jul 1 16:06:34 EDT 2006

Congrats on the find!  Are you also saying that the stumble is fixed?  If so 
it would be interesting, but not really surprising, knowing that the ECU is 
sensitive to low voltage.

What sort of voltmeter do you have?  I don't think the urq ever had a 
voltmeter.  If it is wired per the factory wiring like my old Audi Fox, the 
problem is that the voltmeter is wired into the same circuits that power the 
cabin blower fan.  When the blower was set to full speed the voltmeter would 
read less than 10 volts!  Of course the battery voltage was never really 
that low.  What I found was that the real culprit on the voltage drop was 
the ground.  The current from the fan through the ground wire created a 
voolt or more of drop.  Since the same ground is the reference for the other 
gauges, they would also give faulty readings.  If you find something like 
this, create a direct connection from the gauges to ground.  The +12 supply 
is a bit more difficult ... you need to find a circuit that is switched 
(don't want the meter to wear down the battery after all!) but has very low 
voltage drop from the source.  I suppose if you wanted to know *exactly* 
what the battery voltage was you could dedicate a relay to switch the supply 
to the meter on and off with the ignition ...

Steve B
San Jose, CA (USA)

> Well, I think I have it all licked.  Turns out most of the problem was a
> bad exciter wire D+ on the alternator.  I had to run a new from the
> instrument cluster (pin 12-2).  The motor runs like a champ now.  New
> plugs didn't hurt either.  I am getting 13.8v at the alternator post and
> 13.6v at the fuse box.  Now to figure out why the gauge that reads
> voltage in my dash somewhere, reads a full volt low.  I also still want
> to inspect my splice joint. Thanks for all the help guys.

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