Have you tried swapping the idle control module and have you checked the
valve?

Larry A.

Mike Finkbiner wrote:
>
> 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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