Today's log:
Ah _there_ it is! The idle controller, though behind the glovebox as
advertised, is tucked to the left sideways against the HVAC plenum and
_not_ forward against the firewall as shown in the manual. (Those are
the blower and temperature controllers for the ACC system, and the
fuel pump relay.) It's marked:
002 545 33 32
Leerlaufdrehzahrlregelung
Idle Speed Control 8Zyl.
412.202/010 12V
It is, I might add, a VDO unit and not Bosch. I've come to expect
soldering trouble from VDO's electronics, whereas Bosch's don't seem
to have nearly as much trouble.
Opened, it revealed a LM2901 quad comparitor, two LM2902 quad op-amps,
three signal transistors, one power transistor, sixteen diodes, six
electrolytic capacitors, and the usual handful of resistors and
capacitors. Two of the resistors were mounted on stakes and looked
like tuneable items. (Idle speed being one, I presume.) This circuit
was also varnish-coated, so I hit it with the paint stripper too. The
soldering didn't really look that bad, but it doesn't take all that
long to redo. There were a few spots that looked questionable.
I also pulled the monovalve and had a look at it. It looked good, the
diaphragm was not torn. I cleaned the screen off with a bristle brush
and put it back together. The coil continuity was good, the plunger
was not hydrolocked.
The stupid hood pad fell down again, so I had to glue it back up.
What a pain!
The car started easily, and idled normally. We'll see how it behaves.
...Some have suggested I check into Remco's towing products. They
have a driveshaft disconnector, and a transmission lube pump system!
(As well as tow bars, etc.) That lube pump system looks very
interesting, I bet one of them can be adapted to this car even if they
don't officially offer it.
Driving the car today the idle seemed as before: nothing really wrong
with it. Still seems a touch high, if it bothers me enough I could
try tuning the resistors inside the controller. Maybe someday. The
ACC was definitely heating today, it might even have been overdoing
it. On MIN it switched to cooling (vent only), so mostly it seems to
be behaving itself. The foam tube kept coming off, I think it's about
1/2" too short. I'll glue on the offending end when I get home, that
may have been its only problem.
Once home I had some free time, so I glued on the loose end of the
foam tube. I then pulled out the idle speed actuator and cleaned it
out with carb cleaner. A lot of black gunk came out. Tested on the
bench it seemed to behave properly, so I reinstalled it. The rubber
mounting hoses are a bit loose, but I don't think they're leaking yet.
They're still flexible, so I don't think I have to replace them. With
the engine running a spray of carb cleaner around the valve didn't
result in an RPM change, proof of sorts. I note that the vacuum
advance line to the distributor is purposely disconnected, I'm going
to have to go through the engine vacuum plumbing some time to put it
all right. There was a missing screw on one of the exhaust manifold
heat shields so I dug up a suitable 10mm screw and installed it. That
should help prevent nasty rattling noises, which I hate.
Next up was the AC system. I pulled off the R134a conversion
fittings, there was only a residual puff of pressure. I moved the
Schrader valves from the conversion fittings back to the R12 fittings,
then connected up the vacuum pump and put a quick vacuum on it. It
seemed to hold vacuum, so I then put about 60 psi of propane into the
system, that didn't leak down either (not that I gave it much time,
but I was only looking for profound leakage) and the ACC system was
able to engage the compressor with that little bit of pressure. With
the preliminaries out of the way I vacuumed the system for more than
1/2 hour. It took some minutes before the vacuum pump started making
the rattling noise that indicates that a deep vacuum has been pulled.
I don't know if there was moisture or not, but vacuuming can't hurt,
and a half hour is about the minimum that'll do any real good removing
moisture. Once vacuumed I then charged the sytem with the test
refrigerant: 8 oz. of Isobutane/Propane (R600a/R290) mix, followed by
a propane charge until the system seemed to be operating correctly.
(This takes some time to sneak up on, it's not like you just put in 3
cans of R12 and call it good.) Unfortunately evening was approaching
and it wasn't really all that hot, not good conditions for charging a
system this way. I did see 39 degF vent temperatures, but that's no
great feat under these conditions. Still, it did seem to be working.
Time will tell if I have it charged right, and if the system works
correctly and doesn't leak.
The lights were next. I've been afraid that I might be caught in the
dark with them messed up as they are. I pulled the offending bucket
assembly out of the car and found that the 6-pin connector was shifted
by one position, completely explaining why it wasn't working
correctly. The unused pins were tarnished, suggesting that this has
been wrong for more than a little time. Plugged in correctly, the
lights all worked right. One fog light was still out, but I found
that it was missing a spade connector inside its shell. I replaced
that and then all the lights worked as they should. One of the
mounting screws for the bucket assembly has a broken clip in the car's
sheet metal, it doesn't grab too well but seems to work well enough.
It was time to quit for the night, but I was really having trouble
putting the air cleaner back on. I rerouted the offending fuel line,
which cured the problem.
(For the terminally curious, I have logged 34.75 hours on the car,
and $27 in repair expenses.)
-- Jim
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