Date: Thu, 22 Oct 1998 08:50:42 -0500
Reply-To: Darrell Boehler <midwesty@MIDWEST.NET>
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: Darrell Boehler <midwesty@MIDWEST.NET>
Subject: Re: Digfiant being defiant
Content-Type: text/plain; charset="iso-8859-1"
---------------------
Hi Larry,
Your van should run near normal with the o2 sensor pulled. Possibly your
afm (air flow meter) main spring has relaxed a bit and is causing your too
rich mixture. I have seen afm off enough that the oxygen sensor / ecu could
not compensate enough and the vans ran very rich all the time. I would
suggest you attach a lcd meter to the black wire on the o2 sensor and check
the voltage after running a couple of minutes. Have the o2 disconnected.
Below 0.5 is lean , above 0.5 volts is rich. This may seem stupid as you
already see black exhaust but it will let you know the o2 sensor is
working.
Now if you pop the black plastic top on your afm you will see a wiper
with a contact on it. If you move the wiper to the right is leaner to the
left is richer. See if you can get a reading on the o2 to go rich and lean
by moving the wiper left and right. If you determine the afm is set up too
rich or lean you can adjust the tension on the main spring you see in the
afm. Mark where the black plastic gear is situated before you move it . To
adjust the tension pull the detent, loosen the detent screw is easier, out
of the gear teeth and increase spring tension to run leaner and decrease
tension to run richer. One other little detail, the afm should be adjusted
around 3k rpm and I like slightly to the rich side of the perfect 0.5 volt
reading, about 0.6-0.7 volts. With the voltage adjusted at 3k using the afm
main spring tension now adjust the idle mixture using the idle bypass screw
on the afm box. Double back and recheck at 3 k and idle again, tweak them a
bit if necessary.
Good luck with your quest. One little word of caution it is necessary
that your tune up items be in good shape no bad wires etc. If you have a
leaky injector this will not be good either. So please mark the gear so
you can return it to the original position.
Darrell Boehler
Makanda Illinois
-----Original Message-----
From: Martin's <nitram@TBCNET.COM>
To: vanagon@VANAGON.COM <vanagon@VANAGON.COM>
Date: Thursday, October 22, 1998 7:52 AM
Subject: Digfiant being defiant
>I have a 87 Vanagon with a digfiant efc. Now that the cold weather is upon
>us in Chicago, the sytem is running terrible. The fuel consumption is
>around 16.1mpg (automatic) and the tailpipe is very sooty. ( had been
>18mpg) The engine is surging/chugging and stalling frequently. I
>disconnetcted the O2 sesonrs with no better results. I also checked the
>temp sensors and they were resonable,( as I did not have the exact temp).
>Any ideas ? The O2 sensor is the 3 wire type, and the collant temp sensor
>were new in the summer (I know, that meaningless)
>
>
>
>Thanks,
>
>Larry
>
| 
