Starter Problems?

[Derek Pulvino]

In as much as corrosion is a gradual problem, wouldn't I see some hints of 
harder starting over time as the wiring bungs up?  I don't think it's a 
problem at the battery as everything else works fine (ie lights).

Remember also that it appears there is no current getting to the motor 
itself when it's in the car.  While installed, the starter motor does not 
move or make any noise at all.  I'm guessing my problem is with the trigger 
wire from the key, but I just have a hard time imagining that wire needs to 
carry  very much current to gets it's job done.

Derek P

> > Well, yesterday got the voltmeter out and I do have 12v at both the main
> > power in to the solenoid and the trigger wire from the key (when it's
> > turned).  I did also find that the insulation on the trigger wire is
> > absolutely destroyed on the last 4-inches or so of the wire.  I haven't
> > checked resistance on those components or on that jumper wire.
> >
> > So, after finding the above pulled the starter out and had it bench 
>tested;
> > it turns over fine, but I wonder if a load condition would effect the
> > actuall output...ie if it had been bench tested under load if the motor
> > still would have turned.
> >
> > The other question I had is if volts is really the right measurement.
> > Wouldn't corroded wires restrict the current flow?  Is that were looking 
>for
> > voltage drop under load vs unloaded comes in?
>Now you're getting close to asking the right Qs, Derek.  Resistance or open
>circuit voltage is all but meaningless in this instance.  Hook the 
>voltmeter
>to the power lead at the starter contactor input terminal and measure the
>voltage drop, no load vs. starting load.  Should be only a few volts
>difference.  Do the same at the terminal into the starter from the
>contactor.  By this method you can isolate where the load current losses
>are.  Could be the battery to, do the same at the bat terminals, and the 
>bat
>ground return.
>
>Bernie
>
> >
> > Derek P
> >
> >> At 04:47 PM 12/11/2005, Derek Pulvino wrote:
> >>> Now that I have some light, I'll be checking those things today.  
>Reading
> >>> at Blau, I also saw that there's a large gauge jumper wire that runs 
>from
> >>> the solenoid to the starter motor that can also be suspect.
> >>>
> >>> I'll post back with my findings.
> >>>
> >>> Derek P
> >>>
> >>>> I'd start by checking out the wiring at the starter itself.  There's 
>the
> >>>> big wire that carries power to operate the starter and there's the 
>little
> >>>> wire that comes from the switch to tell the starter to start 
>operating.
> >>>> The former can have corroded contacts and the latter can deteriorate
> >>>> internally because Audi seems to use starter wires whose insulation 
>isn't
> >>>> very good considering the environment it works in.
> >>
> >>
> >> Derek:
> >> Large gauge wire from Solenoid to starter is what carries the power to 
>the
> >> motor brushes.
> >>
> >> For some unknown reason Bosch saw fit to NOT insulate the wire, even 
>though
> >> it carries ALOT of current.
> >>
> >> It is also the major weak spot on the starter.
> >>
> >> Use an ohmeter and check for any resistance between the post on the
> >> solenoid where it attaches ( 10 or 13MM nut) and what appears to be the
> >> starter body ( is actually insulated area for the motor brushes) .
> >>
> >> If you are lucky it might just be some corrosion on the post on the 
>starter
> >> side.
> >>
> >> If not you will either have to replace the lead (with one from another
> >> starter), have the starter rebuilt locally, or a replacement starter.
> >>
> >> HTH
> >>
> >> -Peter
> >>
> >> 1991 200 20v Q Avant Titan Grey
> >> 1991 200 20v Q Avant Indigo Mica
> >> 1991 90 20v Q Red
> >> 1990 CQ silver (awaiting S2 engine transplant)
> >>
> >> 1990 CQ red ( to part or not)
> >> Chelmsford Ma, USA
> >>
> >
> >
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