Date: Thu, 9 Sep 1999 22:46:35 -0600
Reply-To: "Jon B. Kanas" <kanas@QUALITY.QADAS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Jon B. Kanas" <kanas@QUALITY.QADAS.COM>
Subject: Noisy Failure Response
Content-Type: TEXT/PLAIN; charset=US-ASCII
Tim and fellow listers,
Your failure is really interesting to me in a couple of respects, so here
I go on some wild a** guesses as to what has happened. The black smoke at
the time of the "final" gasp and the soot in the exhaust port are, IMHO,
the great clues. I suspect that when the cross-pipe finally separated
from the bus that the exhaust reaching the oxygen sensor (if any) was too
cool, causing the injection computer to think that the engine had just
been started and was still cold. It went to a very rich mixture causing
the smoke, soot and poor running. In my experience, loss of exhaust back
pressure can cause rough running, and some loss of power, but not a
failure of the magnitude which you describe.
I doubt that you have dropped a valve; Normally when this happens, the
engine will seize almost immediately because there is a large foreign
object in the combustion chamber (the valve head), and it won't run at
all. No smoke, no nothing. Dead. Can't even turn the engine by hand.
I think the bus won't start for a much simpler reason Check the battery
connections on the back of the alternator. One of the big red wires goes
to the battery, and the other to the starter. If the starter one is not
properly connected, there is enough power via the wiring loom to trigger
the starter solenoid, but there is no power to the starter motor. The
solenoid closes the circuit with a click, but there isn't any electricity
coming down the big red wire to drive the starter motor. When these
connectors get loose, either at the nut or between the wire and the
connector, the battery can be effectively disconnected from the starter.
Every Vanagon I've owned has eventually had a failure of these connectors,
and they can be VERY deceptive when troubleshooting. This problem would
also explain why the bus would run, but will not start. All of the
additional vibration caused by the exhaust leak may have driven an already
weak connection to final failure.
The Brake Light is, in some way which is mythical to me, coupled into the
alternator warning circuit. Volkswagen has done this since 1968 for
reasons I do not understand. If the alternator quits, both the brake and
alternator lights come on; If the brakes quit, only the brake light comes
on. If you had a very low idle (probable), the alternator quit charging
and both the brake and alternator warning lights would come on. If you
have a wiring problem at the alternator, similar to my description above,
it would not surprise me if a symptom was the errant Brake light.
The blinking oil pressure light is normal; this is how they behave.
There's a buzzer imbedded in the oil warning system too which can be
really entertaining under select circumstances. Let's say that you didn't
notice that you knocked the wire loose on the oil pressure sensor when you
were draining the coolant out of the engine. Lets say you're driving home
from Denver (50 MI) in the middle of the night when you finally hit THE
bump which is firm enough to cause the wire to finally fall off the
sensor, and wedge itself against the push rod shield, effectively
grounding it. Wow!!! Blinking red lights, screeching buzzer, tow home
two hours later, 5 minute fix the next morning, several choice comments
from spouse. Don't ask how I know about these things.
Regards and good luck,
Jon Kanas
jon.b.kanas@lmco.com
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