4000S intermittent no start

[Huw Powell]

> My friend Linda K appeals to the collective for some troubleshooting
>  advice on her 1985 4000S. (Automatic)
> 
> Car shows intermittent no-start.
> 
> We know the gearshift lockout switch is incorrectly adjusted, because
> it will start and move in 1st and reverse (when it starts). Where is
> this switch? Under the car? Inside the console? I need to go look at
> it.

I believe the originating switch is in the console at the shifter lever
itself.  This switch triggers relay #8 in the fusebox, which allows the
12v from the ignition switch to reach the starter.  Since it is easy,
I'd start by checking what is happening there.

Manual transmission cars
come with a little brass jumper installed there, since they don't need a
lockout.  With the relay bypassed the lockout switch will be irrelevant 
to the problem.  Bad ASCII art:

     ____

I
I         ____  <<< jumper goes between these two slots.
I

     ____

But definitely fix that switch misalignment before the repair is
considered "complete"!

> I'm thinking starter (if this has an integral solenoid) because when
> it doesn't start, there's nothing - no click, just silence. If she
> comes back "later" which can be a few hours or a few days, away it
> goes, and it runs well.
> 
> I've told her to try this - next time it doesn't start, turn on the 
> headlights and try again - if the lights stay bright, she's got a 
> problem in the switch, lockout switch, or solenoid - if the lights
> get dim, it is the starter motor.

It does have an integral solenoid, and your troubleshooting advice is 
valid.  The other test is to whack the starter with a hammer.  If that 
"fixes" it, it's time to order that new starter...

> One "mechanic" thinks it is "the computer" - but he's shotgunning 
> while she's paying the bills.

Correct, that "mechanic" needs to get some fresh air...

> Anything else or anywhere else I should be looking?

No, it sounds like you have the whole chain of possible failures sorted 
out, it's just a matter of testing each one in order.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/