[urq] intermittent start issue

[urq]

Over the years and several older Audis I've come to understand that there is
not a single issue, rather it is the combination of several factors that
leads to hot start cranking issues.  Time and temperature cause the voltage
drop across the start switch and wiring to the solenoid to increase, thereby
reducing the voltage available to the starter.  I measured less than 9.5
volts at a starter that was not pulling in.  The heat soaked starter causes
the magnetic field within the starter to work less efficiently.  Many times
the heat shield Audi originally installed on the starter disintegrates, or
is not reinstalled when the starter is replaced.  This increases the effect
of the heat related issues.  Your experience with moving the car in gear and
getting a starter to pull in is a sign that the brushes in the starter are
getting bad.  

VW had a TSB for our Audi's cousins which added a "load reduction" relay
between the starter switch and solenoid if the voltage at the solenoid was
less than 9.5 volts.  If you are considering adding headlamp relays to make
headlights brighter you may want to add a starter load reduction relay at
the same time.  Doing so will likely make your cranking more reliable, but
eventually other things will deteriorate and cause starter issues.

I must say that IME, simple replacement of the starter restores the car to
reliable starting.  The early US urqs had a stamped sheet metal heat shield
that covered both the solenoid and the motor itself, but the newer cars seem
to protect only the solenoid.  I found a nice insulation and foil sandwich
heat shield for the 5000TQ that goes over the solenoid.  When I install a
replacement solenoid I install one of these heat shields.  I did not find
them in the garage to get the P/N, but they are in the FA.  

Steve Buchholz

-----Original Message-----

Chaps
Bit of an issue with getting the old girl fired up.
I used to use my WR every day but since last October I spent a lot of
time,effort and cash having it resprayed and have decided to look after it -
it is now garaged when not in use and is only used at weekends when the sun
is out and no rain is forecast for a fortnight. Anyway, it seems this might
not be the best policy because I now have in intermittent starting issue.
Fine starting from cold. Go for a run, get it up to temp. Stop, park up and
leave for a few minutes and then sometimes it will not start. The solenoid
will click but the starter will not engage. If I rock the car with it in 1st
gear - something that used to work on my my first car (VW 412LE) it will
start.
Is this a sign of a low charge battery (because of all the standing around),
a dying solenoid, a dying starter or something more serious. Once started it
goes like a train.
Any suggestions gratefully received (especially ones that solve the problem
with minimal time, effort and cash!)
Look forward to hearing from you
All the best
Keith

'87 WR
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