Date: Mon, 20 Jan 2003 02:47:36 +0000
Reply-To: Mike Finkbiner <mike_l_f@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike Finkbiner <mike_l_f@HOTMAIL.COM>
Subject: Aren't intermittant electrical problems fun!
Content-Type: text/plain; format=flowed
Volks -
I have had a couple over the last few years, and now I'm fighting an idle,
acceleration, bucking problem.
This is an '87 Westy with a 2 yr old Boston Bob 2.1. The O2 and Temp II
sensors have just been replaced, and I have had the same results with two
different ECUs. We have swapped out the throttle body and throttle position
switch for another used one that looks good. A VW specialty mechanic has
done the recent work trying to diagnose the problem.
When the engine starts, even in this chilly weather, it runs OK. As the
engine warms up I can use my Digitool to watch the Temp II and Oxygen
sensors. When the O2 signal starts to bounce back and forth, indicating
that it is at operating temp, I start having intemittant bogging down while
accelerating from a stop sign. It can also buck sharply when I'm
accelerating at low RPM, generally just once.
Then, once the engine is fully warm, I begin to have idle problems. While
sitting at a stop sign or in my driveway, the tach will bounce around 8-900,
sort of a lumpy up-down. After a short time, it will start sagging and
recovering, then sometimes drop off to nothing for an instant and recovering
to idle above 1100, then back down again. Friday night I noticed that the
Fuel Injector Indicator on the Digitool was going dark when the engine idle
dropped off. Since then I have noticed the same thing, but had to look
harder during the day.
It gets it's signal from pin 12 on the ECU, which is sending the fire signal
to the injectors. I can't tell if the signal cutting out means that there
is a problem with the connector to the injectors, or if there is something
else confusing the ECU.
I have tried wiggling the Hall sender connector, with no effect. I suppose
this could be a ground problem, but a couple of years ago I pulled, cleaned
and greased all of the connectors that I could find on the van. I have also
added an additional ground from the ECU to the engine block.
So - continuity problem in the harness, problem with the Hall sender? Bad
JuJu?
Why does it only really act up when the engine is fully warm? I can have
the bucking problem once the O2 sender starts bouncing around, but the idle
problem only seems to happen once the engine has been driven for awhile.
- Mike
Mike Finkbiner
'87 Westy
Moscow, ID
mike_l_f@hotmail.com
Perception is more real than truth, and belief turns truth into lies. -
Kedar Nan
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