Date: Fri, 14 Aug 1998 16:06:41 -0500
Reply-To: Darrell Boehler <midwesty@TAOS.MIDWEST.NET>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: Darrell Boehler <midwesty@TAOS.MIDWEST.NET>
Subject: Re: 87 Vanagon hesitation chapter (3)
Content-Type: text/plain; charset="iso-8859-1"
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Hi Kay,
This looks more like an ECU all the time. There is one wire from the
ECU pin 19 to the left engine head. Measure this wire to make certain it
is good. It provides the ground path for ECU O2 sensor circuit. The other
ground ECU pin 13 is used for all the other circuits. Most newer
applications now use 4 wire O2 sensors that connects the O2 plus and minus
directly to the ECU O2 circuits. Maybe a 4 wire O2 sensor would be a good
upgrade for our vans. This would eliminate the need of the O2 sensor circuit
relying on a ground path that includes exhaust pipes, exhaust manifolds, and
cylinder heads and finally a connector, wire , and then ECU pin 19 before it
completes the circuit.
I posted this to the list because some may want to know one of the
reasons cleaning the connectors always seems to help our vans run better.
Darrell
-----Original Message-----
From: Kay O Fremgen <kayfremgen@JUNO.COM>
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: Friday, August 14, 1998 12:55 PM
Subject: 87 Vanagon hesitation chapter (3)
>Hi again,
>
>Darrell thank you very much for still hanging in there with me, and also
>to Bill and Mark for participating in Chapter 3. Hate to disappoint you
>guys but I'm a Male, first name is spelled Kay ( thanks to a German
>grandma) but it's pronounced as Kai.
>Lets see if I can get everyone brought up to date.
>With O2 sensor connected I have hesitation under load more sever with AC
>compressor on.
>With O2 Sensor disconnected the van accelerates just fine.
>
>87.2 Westy automatic
>VIN # WV2ZB0254HH079343
>MOTOR# MV 029505*
>
>Air flow meter: OK
>Fi temperature sensor: OK
>Throttle switch: OK
>Fuel Pressure: OK
>Exhaust leaks: None
>O2 sensor: OK (have exchanged the sensor 5 days ago with no improvement)
>
>Observations:
>The old and new O2 sensor when connected to ECU are giving me up to
>"negative" 0.1 volts for about 3 to 4 seconds under load (AC compressor
>on). Which is approximately the duration of the hesitation.
>During deceleration above 1250 rpm (fuel gets cut off to the injectors)
>my volt meter is showing me "negative" 0.05 volts with AC compressor off,
>and "negative" 0.1 volts with AC compressor engaged.
>
>Darrell you wrote:
>" My 86 has 0.5 volts on the ECU end of the wire with just key on or when
>running and the sensor disconnected" my wire reads 0.06 volts. (isn't pin
>#2 looking for an incoming signal from the sensor? Why is it sending
>voltage? Could this be my problem?)
>You also wrote: "Does your Bosch have the 022D or just 022", my data on
>the sticker that is attached to the computer reads as follows:
>
> Bosch
> 0 261 200 065
> (810)
> DF VW 025 906 022
>
>You wrote: "Does it only happen coming off idle?" No. It happens off
>idle 3 to 5 seconds of hesitation, 1500 rpm and up: 2 to 3 seconds
>hesitation, 1800 rpm and up: 1 to 1.5 seconds hesitation, 2000 rpm and
>up: starts becoming unnoticeable.
>
>Which leaves us with:
>Why the "negative" voltage from the O2 sensor?
>The coax wire (green) connected to ECU and the O2 sensor disconnected,
>reads 0.06 volts versus 0.5 volts (which is the number you are giving me)
>with engine running.
>By observing the O2 sensor hooked up to the ECU with the volt meter, why
>does it take the computer so long to bring the fuel mixture back up to
>0.5 volts? (this sometimes takes up to 6 seconds)
>
>Open to any suggestions, if you need me to measure anything just holler.
>
>Thank you,
>Kai
>
>
>
>
>
>
>
>
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