1984 4k - no start

[Bares, Vittorio]

Yup, quattro. I see there is a bung on the end of the downpipe just
before the cat - but no O2 sensor (seems to be capped)?

I thought it might be a hot start - however, it doesn't always cold
start either.

Vittorio -

-----Original Message-----
From: Huw Powell [mailto:audi at humanspeakers.com] 
Sent: Thursday, August 13, 2009 5:15 PM
To: Bares, Vittorio
Cc: Ben Swann; quattro at audifans.com
Subject: Re: 1984 4k - no start


> As for the O2 sensor - err, uh - ETKA says it has one - I'd expect it
to
> be on the exhaust downpipe somewhere - but I don't see one - this is
an
> '84 - any ideas?

It's mounted on the top of the front of the catalyst.  This is a 
quattro, right?

> I'll move one of the additional battery to motor grounds to the
firewall
> (Huw, I think that is what you were intending when you mentioned that
> the one to the motor is for the starter?) - read that in one of the
old
> '4k no start' threads from like 1998.

Yes, the starter is the heaviest load the battery ever runs, hence the 
hot wire directly to it.  It's nice to have a fat ground to a tranny 
bolt to complement it.  And see below...

> Hmm - I thought - perhaps this is heat related? So, I ran the car for
a
> while, no more than 5min - turning it off, then on again, 3rd time I
> tried this - no start. Had to leave to return the borrowed parts so
> didn't have a chance to go through the tests again.
> 
> When I got back, sure enough it started right up - but this time on
the
> first attempt of turning it off and on - it didn't start.

OK, so potentially the whole problem is a hot start one?

Those early 80s Audis have quite a few hot start issues, some of which 
they were beginning to address.

One thing you might want to do is measure the current the starter is 
drawing (most competent garages should have a clamp-on current meter 
that will do this).  My coupe once had a bad hot-start problem, turned 
out the starter was drawing ~200 amps, in turn pulling the battery 
voltage too low to run the CIS.  New starter made problem go away 
completely.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/