Date: Wed, 26 Dec 2007 18:52:07 -0800
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: 1.9 low power problem
In-Reply-To: <555480.96710.qm@web81714.mail.mud.yahoo.com>
Content-Type: text/plain; charset="us-ascii"
The splash shields are nice to have on there, but they don't really do that
much. Not likely that they alone are a major factor.
I can't quite agree with the "02 is signal is ignored if the ecu doesn't
like it.
The ecu will try to deal with a dead 02, it just can't do anything with that
signal, I don't think it knows to quite ignore it. Perhaps you meant it
can't do much with a dead or shorted 02 signal. But I don't think it's
smart enough to go 'ooops, this doesn't' make sense, I better ignore it'
...........I think it would just stay in open loop - just like it would if
the 02 was disconnect.
For one, the 02 has to be warm enough to produce a signal and then the
system is in 'closed loop' . If he 02 is dead, then it would run in open
loop and not run as nicely, burn more fuel etc.
It can run with the 02 disconnected.
Checking that the 02 is shorted by water is a very good thing to look into.
You should always read what the 02 is doing with a meter. You tap into the
signal wire and you'd like to see swinging voltage, like .4 to .8 volts,
something like that. If it's say .5 volts continuous, it's dead - this is
well warmed up.
02 is out of the picture during wide open throttle I believe.
I would sure be spraying electrical things with WD-40 if running in the wet
makes it run poorly. I like the checking for water shorting the 02 signal
though.
Man, I would love to have a whole bunch of 'switch-in standard default
signals' ............one for 02, one for ecu temp sender, etc. Then if you
think a sensor is faulty, as a test you just switch in the 'standard
mid-range default value' straight to the ecu, and if that removes the
symptom, you know exactly where to look. It's really fun when you can play
with the system this way. It's not even that complicated. A few inputs
here and there, and the ecu ( and ignition system if you have a 1.9 )
controls spark, when spark occurs, and how long the injectors are open.
It's quite odd that the ecu can't tell if the Cat is doing anything.
In more modern systems, OBD-II, there's an 02 downstream of the cat and
the ecu can tell if that's working. Some systems even shut off fuel to
individual misfiring cylinders. All fun !
Scott
www.turbovans.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Evan Mac Donald
Sent: Wednesday, December 26, 2007 12:23 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 1.9 low power problem
I am so sorry - i should have said "...and APPEAR after driving for a
while..." This is because the O@ sensor is ignored by the ECU until its
signal "makes sense" to the ECU, but it may not be the right signal for
conditions...
Brendan Slevin <brendan@BELLATAZZA.COM> wrote: These symptoms did start
after driving through tons of rainy slush and snow.
But, they don't go away after awhile, they might not get worse, but they are
certainly persistant and not going away. Also, should there be some kind of
splash guards on the sides?s
Brendan Slevin
Roastmaster
BELLATAZZA
tel 541 593.9750
www.bellatazza.com
I have measured out my life with coffee spoons. -T.S. Eliot
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Evan Mac Donald
Sent: Wednesday, December 26, 2007 11:56 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 1.9 low power problem
IF these symptoms arose AFTER the van got wet, AND go away AFTER running
awhile, the O2 sensor is a suspect. Unplug the sensor wire, and try the same
driving course, to try to duplicate the problem...
Brendan Slevin
wrote: Well, Totoro has been
running great since the rebuild but now (last three
days) has developed a hesitation. It drives fine in town but when I try to
get on it to get up to highway speed in 3rd or 4th it bogs way down and if I
don't lift seems as though it would die all they way. If I lift my foot and
slow a bit and down shift it seems fine again until the instant I try to
speed up again. Happening right around 4000 rpm on the tach. Plugged cat
maybe? I took some connections apart and cleaned them with elec. Cleaner in
a spray can. Even unplugged the ecu and plugged it back in. I did this all
this morning before starting the van. When I started it and warmed it up I
took it for a test drive. Was fine for about three miles and then started
it again. We've had a ton of snow and slush last week so I think something
got wet. Maybe the water causing the problem was frozen this morning (25
degrees F) and didn't cause a problem until thawing out. Also, am I
supposed to have and splash guards around the engine? Seems to be hole to
mount some on both side in the wheel wells.
Brendan
I have measured out my life with coffee spoons. -T.S. Eliot
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