5ktq electrical issues update...

[Cody Forbes]

Well going on the advice to work on the charging issue first I took the
alternator off and went through it. Found some things I didnt like (bad
grouve worn in one comm ruiing my new brushes, plus some broken plastic
bits) so I swapped my new regulator into another alt and cleaned off all of
the mounting brackets beofre re-installing. My father wanted to go with me
on the test ride and he setup his DMM on the battery for the trip. Battery
was at 12.6v engine off, and charged to 13.8v at idle. Lights on dropped it
to arrond 13.4v, A/C with lights put it at 13.2v. Then driving down the road
I noticed all of the sudden it was loosing charging capacity. Crusing with
lights on we saw 13.45v starting to drop at about .01v per second. Our test
was cut short when I was coasting up to a light and the rad fan turned on,
killing the engine and I haven't gotten to tuning the hot start stuff so it
took a good half hour to get it going again. Once on the road again (without
my dad, he had called somebody so he could go get our trailer and tow me
back) I noticed that it would no longer charge past 13.3v, and dropping
steadily. When the rad fan turned on it would go to 13.0v and now the engine
is breaking up (badly) at even that voltage which is making test drives a
real headache. On the return trip I leaned it out significantly which helped
a bit because it was getting very loaded up when the fan was on.

Once back at the shop I went to the next most suggested place to look, the
battery cable splice. I had to follow the cable up under the carpet because
I've never found this splice before, but once I found it I realised I HAD
found it before just didn't pay it any attention. After cutting off the very
stubborn shrink wrap I found yet another thing on the car that could
contribute to this problem and needs to be replaced. On the side of the
splice that leads to the battery there was plenty of green corosion, but
worse is the side leading to the engine compartment. It apears to have
fiberglass insulation on it, but under that insulation is one very burnt up
wire, that was hot when I got to it after the car has been sitting for 30min
so I couldn't immagine what it was like with the car running. At this point
it was dinner time so I called it a day. I plan on cutting the cable before
the green corosion and replacing it most if not all of the way to whever it
ends (starter right? didn't look yet) with some brand new 4 gauge wire, or
since I'm really low on funding and I have a bunch of 8awg wire here I may
have to double up on that instead. I know this was a problem, possibly the
fix to the charging problem, but do you think it would be the ignition
problem too? Conciveably the bad wire wouldn't have been able to pass the
amperage for everything under the hood, but shouldn't the alt have been
supplying the amps under there anyway?

I am still trying to get ahold of a scope to check the ignition, my EE
friend is away for a few days. Also I got real behind on my email and still
have a bunch of things to read on this thread. I'd like to say again guys,
thanks for every suggestion, no matter how obvious or far fetched it may
have been. If ever in south Florida make sure to stop by and pick up your
drink of choice!


-Cody Forbes
Black Forest Racing
2x '86 5ktq
'87 5ktq
'88 80 4cyl


----- Original Message -----
From: "Larry C. Leung" <l.leung at juno.com>
To: <quattro at audifans.com>
Cc: <blur at sympatico.ca>; <Cody at mail.craincorporated.com>
Sent: Thursday, October 02, 2003 10:50 PM
Subject: Re: quattro digest, Vol 1 #5433 - 15 msgs


> Had anyone checked the Positive Splice to the battery under load?
>
> HTH,
>
> LL - NY
>
> Date: Thu, 02 Oct 2003 10:45:23 -0400
> From: B Vibert <blur at sympatico.ca>
> To: Cody at mail.craincorporated.com
> Cc: quattro at audifans.com
> Subject: Re: 5ktq electrical issues update...
>
> Why is the car getting low in voltage?  Is there a heavy load somewhere?
> Something shorting out?  Perhaps it's not the cause but the effect.
>
> Burl Vibert
> 1987 5kcstq
> Kingston, Ontario
>
>
> Cody wrote:
>
> >My problem is voltage related. The car only misses when voltage is at or
> under 12.8v. The knock sensor should not detect more knock just because
> the voltage is lower.
>
>