Date: Thu, 24 Mar 2011 18:08:45 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: Engine analyzer/tach recco?
In-Reply-To: <1301003004.23070.144.camel@TheJackUbuntuNetbook>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:43 PM 3/24/2011, Rocket J Squirrel wrote:
>I was asleep at the back of the class when that post came out. Can
>someone point me to it?
I can, I made it. Wait one.
=================================
We got Sally's ('85 1.9l Westy) alternator bracket dealt with,*
cracking bleeder valve/big hose coupler replaced, heater box back
together, and dash reinstalled except for heater controls some weeks
ago, and she's been driving it.
*and there's a Santa Fe shop that needs to go on the list as both
incompetent and stinkers.
Today we tackled driveability and mileage. When Sally came to me she
was idling around 1500 rpm, which worked because the closed-throttle
switch wasn't working. It was also as low as you could get with the
idle screw, so I machined a little extension on the plug that let it
extend in far enough to touch the butterfly - this let the idle come
down. I didn't chamfer the edge so it whistled loudly with small
throttle openings, and the switch adjustment was stuck; so for the
present I substituted a 2.1l throttle body I had for Sally's (which
was also a 2.1l, curiously enough). With that I could get the idle
down to where the idle stab started to work; but it was running rich,
bad mileage, and if you declutched and let the engine idle from 2k or
so it might very well almost die then recover, or occasionally it
might just die. It was very boggy until about 2k and not very strong
above that.
We knew that at least three people had breathed on the AFM and
someone had pulled the cover off the idle mixture screw; and the last
person in the AFM "adjusted it for the 7,000 ft altitude" of Santa
Fe. Millee commented that whenever she stopped the vehicle at the
artist's residence where she spent the summer there, people would ask
here what the gasoline smell was. (!)
T-I and T-II senders tested normal. We checked fairly carefully for
air leaks into the intake system. Putting a scope on the O2 sensor
showed the ECU operating in closed loop, but with sensor voltage
going above 0.8 volts and just barely dipping below 0.5. Tailpipe
smelled very rich.
We applied this method:
http://www.thesamba.com/vw/forum/viewtopic.php?t=356377&highlight=afm+adjustment
to adjust the AFM. When we began the idle mixture screw was out 6
1/3 turns, the wiper position had not been disturbed and was lined up
precisely with the bottom edge of the carbon track, and the spring
was at some unknown setting.
After a couple of adjustment cycles we had not changed the wiper
position, the mixture screw was out 1 5/6 turns instead of 6 1/3, and
the spring was thirteen teeth clockwise (stronger) than before. This
was not perfect, but it was well within the range that the O2 sensor
and ECU could deal with in closed-loop mode, so we left it at that
for the present and called it good. The switch on Millee's throttle
body had been adjusted - a trial fit revealed that with the extended
idle plug screwed all the way in we still could only get down to
3,000 rpm idle! So we put mine back in and went for a drive. It
behaved just as you'd expect a 1.9l Westy to, and Millee was
gleefully amazed. So was I - at the combination of things all wrong
at once that *had* to be all wrong at once for it to idle with the
existing setup.
There's still an occasional unexplained engine stop when declutching
at low speed (n of 2 so far). We were too busy appreciating the
otherwise normal behavior to be studying the tach at those points.
A good day. More odds and ends, the transmission still to swap, and
a really nasty throttle body to try to rebuild - but the great ship
Sally sails again, and people aren't gagging as she sails by.
Yours,
David
