Date:         Mon, 13 Apr 2009 19:34:26 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Loss of Power after carwash
Comments: To: Michael Sullivan <sandwichhead@GMAIL.COM>
In-Reply-To:  <eccfedcc0904131548ja31133q853d00d4cd8a1015@mail.gmail.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 06:48 PM 4/13/2009, Michael Sullivan wrote:
>Well, still having the same loss of power.  Gonna try step by step
>diagnosis. I unhooked the green wire from the o2 sensor, no change.
>Unhooked the harness from the o2 sensor and still no change. Will pull all

Did you do the spraying with the engine running (manual says don't)?

What does the *unplugged* green O2 sensor lead measure with engine
running?  It should be close to a half volt with a digital or
sensitive analog meter.  If it's zero, the lead is shorted to ground,
probably at the end of the coax.

What does the sensor itself read?  Unplugged, it should read ~zero
with the engine decelerating from high rpm with throttle
closed.  Otherwise should read either near zero or near .7
volts.  Plugged in, it should read about half a volt until engine
starts to warm, then should oscillate between ~0 and ~.7 as the ECU
follows the mixture.  On a digital meter that will show up as
apparently random readings; that counts as ok.

Are all cylinders firing?  When you gingerly lift the connectors from
the distributor, can you lift an equal amount before each cylinder
stops firing?   Could a plug body be cracked?  Any problem with
high-voltage insulation will get worse as cylinder pressure goes up.

Is it breathing freely? Any possibility that you thermal-shocked the
CAT enough to break the innards?  If you put your hand over the
exhaust does it build up pressure normally and then puff out all at
once when you take your hand away?  What do your manifold vacuum
readings look like?

Did you have the plug leads off for any reason?  The engine will idle
fine on two cylinders, but has no grunt.


  --
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'89 Po' White Star "Scamp"