GTV-6 electrical problem(s)

[Joe Elliott <jee@xxxxxxxxxxxxxx>]

I had some issues with my '82 GTV-6 on the way to school last week, 
which kind of worries me since I don't exactly have tools, free time, 
or a garage while I'm here for the semester.

The first problem was a stumbling under low-RPM acceleration when the 
EFI was in closed-loop mode.  This had been going on for awhile, but 
only when the car was cold.  I assumed that it must be a poisoned 
oxygen sensor since my car burns a *lot* of oil so I replaced the 
fancy-pants Denso sensor I got from Ian Lomax a while ago with an $18 
OEM Bosch one from AutoZone.  Of course I didn't get this done until 
the night before leaving for school (you know how it is when you're a 
college student working 45hrs/week all summer until the day before 
you drive your 20-yr-old, $450 Alfa 300 miles to go school, and try 
and get a semester's worth of maintenance done before you leave...or 
maybe you don't).  When I set off, it ran rough in closed loop like 
it had before, but I was at speed before the car warmed up, so I was 
at worst slightly annoyed.  Then I got stuck in 5+ miles of 
bumper-to-bumper traffic in Columbus.  Despite being fully warmed up 
for a couple of hours, it continued to stumble in closed loop mode. 
Stop and go traffic became quite a pain in the ass when I had to 
essentially floor it to accelerate smoothly.  This nonsense and the 
slipping the clutch that was associated with it got the car hot 
enough that the overtemperature warning light came on for the second 
time in the 4 years and 32,000 miles that I've put on the car (first 
time I was stuck in traffic in August with a failing water pump and 
only one cooling fan) and I had to turn the aircon off.  When I got 
to school I just shorted the terminals on the full-throttle switch so 
that it runs in open loop mode all the time, and sure enough, the 
problem is gone.  But that's not a fix, that's a workaround, and if 
anyone has any idea what the real problem is (ECU?) I'd love to hear 
it.  The oxygen sensor works fine for my fuel/air mixture gauge, by 
the way.

A little beyond the Columbus traffic jam I ran into heavy rain that 
necessitated turning the wipers on.  When the wiper motor first came 
on and drew peak current, the radio blipped off for a moment.  I 
repeated this several times to verify it, and also discovered that 
when the aircon is off the problem doesn't occur (cooling fan and 
electromagnetic clutch probably draw a lot of current so this didn't 
surprise me).  In my experience, this problem on a GTV-6 indicates a 
dirty junction where the alternator, battery, and fusebox come 
together in the left front of the engine compartment.  But upon 
reaching my destination, this connection turned out to be clean and 
tight.  Also, I drove the car at night a couple days ago, and the 
alternator light appears to be glowing brighter than usual.  What's 
the deal?  (I checked alternator output voltage the morning I left 
home, by the way, and it was spot on at 14.3V, but that was with no 
accessories turned on.)  I'm tempted to suspect the ignition switch 
and related wiring since it seems to have been messed with by the PO, 
but my radio's on a relay so it's only drawing like 5mA through the 
ignition switch, and the aircon stuff is on relays from the factory. 
The wipers aren't though, unless the box that controls the 
intermittent wipe also functions as a relay to keep the wiper current 
from going through the ignition switch.  So I figure it would have to 
be the fuse box, but I just cleaned all the fuses and holders a month 
ago, and I had the whole fuse box disassembled a couple years ago at 
which time I cleaned every single contact in there.  But what else 
could it be?  If it were the alternator, the battery would cover for 
it (and eventually die, which hasn't happened), right?  So it has to 
be the wiring between that junction and the affected systems, right? 
Is there anything that I'm overlooking?

Could it be that the two issues are related?  I haven't tried using 
the wipers since I shorted the full-throttle switch, so besides the 
alternator warning light glowing more than usual, the problem has 
gone away for all I know.  Is there any way that a screwed-up ECU in 
closed-loop mode would draw a bunch of current and cause this 
apparent lack of electrical power that I associate with dirty 
junctions?

TIA,
Joe Elliott
'82 GTV-6
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