Date:         Tue, 3 Feb 2015 19:52:42 -0800
Reply-To:     Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject:      Re: Removing stuck O2 sensor
Comments: To: James <jk_eaton@HOTMAIL.COM>
In-Reply-To:  <BLU177-W15486D7EC57C58213A14A4E03A0@phx.gbl>
Content-Type: text/plain; charset="us-ascii"

Thanks James,

I suspect that too; the buildup is absorbing some of the injected fuel until
it heats up.  It's a common problem with any FI system other than direct
injection. The new O2 sensor fixed the idle hunting and it runs great when
warm, the cold running miss is really minimal. I have not used Seafoam, but
I'll try it!

Thanks,

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
James
Sent: Tuesday, February 03, 2015 7:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Removing stuck O2 sensor

A low or stumbling idle when cold that clears up when the engine is warm
(and is not the O2 sensor) is nearly always carbon on the intake valves in
VW engines - I've had this in CIS, Digifant and far more modern engines.
Seafoam or other intake valve cleaners will make a big difference in a
hurry.

VW engines are infamous for carboned intake valves - in the glory days of
the CIS system, we were advised to run Chevron's Techron intake valve
cleaner through every 5000 km or more often.

James
Ottawa, ON

> Date: Mon, 2 Feb 2015 10:46:51 -0800
> From: stuartmacm@GMAIL.COM
> Subject: Re: Removing stuck O2 sensor
> To: vanagon@GERRY.VANAGON.COM
>
> It's really more of a low idle when cold that causes off-idle stumble
> for the first few minutes.  I set the idle to 850 and it comes up
> 50-100 rpm when the ICU is plugged back in, and then lopes +- 100 rpm.
> All grounds have been checked and cleaned, and the T2 socket is good
> (this is a rust free California/Oregon van). Only original parts are
> the idle control valve (which hums, but not all the time, should it?),
> PCV valve (could that cause the problem?), and the Hall sender.
>
> I've installed rebuilt injectors, as well as a used ICU (original had
> a burned component), Temp 2 sensor, adjusted the TB switch & cleaned
> the TB, fuel pump and filter, all new tune up parts, but carbon on the
> intake valves is a possibility.  We will be running top tier gas and
> see what happens, or we may just have to live with it.
>
> After a great experience with a rebuilt 2.1 upgrade in my '84 15 years
> ago, I wish I could just replace all this unnecessary complication
> with the 1.9's Digijet injection system until we can do a Subaru
conversion.
>
> The Digifant system is just an overly complicated attempt at keeping
> an obsolete and inefficient engine in production for too long.
>
> Stuart
>
> -----Original Message-----
> From: Dennis Haynes [mailto:d23haynes57@hotmail.com]
> Sent: Sunday, February 01, 2015 9:23 PM
> To: 'Stuart MacMillan'; vanagon@GERRY.VANAGON.COM
> Subject: RE: Removing stuck O2 sensor
>
> For the stumble when cold you need to look at the injectors for spray
> pattern and check for excessive deposits on the intake valves and
> possibly worn intake guides. For the idle hunt this is sometimes
> common. What is the idle speed with the idle valve unplugged? This
> should be about 800 on a warm engine. The idle valve needs to always
> provide some boost to be ultimate control. Normally they shoot for
> somewhere between 850-950 rpm.  For the temp 2 sensor I find that many
> of the aftermarket ones are not quit right and bad ones come in
> batches. The OEM ones rarely go bad. Most of the time problems with
> this circuit are due to the connector or the wiring near it. A bad
> ground on this circuit creates a lot of havoc as it is shared with the ECU
and idle speed controller.
>
> Dennis
>
> -----Original Message-----
> From: Stuart MacMillan [mailto:stuartmacm@gmail.com]
> Sent: Sunday, February 1, 2015 11:04 PM
> To: 'Dennis Haynes'; vanagon@GERRY.VANAGON.COM
> Subject: RE: Removing stuck O2 sensor
>
> Well, maybe I will leave it as is, this van is exempt from testing.  I
> still have a cold running stumble, and a slight idle surging when warm
> (900-1000, up and down) after the temp 2 sensor replacement.  I'm
> pretty much out of options now, but I'll look for a vacuum leak before
> I turn it over to a shop.
>
> Stuart
>
> -----Original Message-----
> From: Dennis Haynes [mailto:d23haynes57@hotmail.com]
> Sent: Sunday, February 01, 2015 5:47 PM
> To: 'Stuart MacMillan'; vanagon@GERRY.VANAGON.COM
> Subject: RE: Removing stuck O2 sensor
>
> It's not the lift, but having the oxy acetylene torch and knowing how
> to use it. I last wasted money on the Map gas torch some 25 years ago.
> It is really limited to brazing soft materials. Need to get steel red
> hot fast, your need the real deal. Must be nice to live in an area
> where a shop will remove a catalyst. Without the cat you may not need
> the O2 sensor. The O2 sensor is there to make the cat do its job.
>
> Dennis
>
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of Stuart MacMillan
> Sent: Sunday, February 1, 2015 1:50 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Removing stuck O2 sensor
>
> You can do that because you have a lift!  I've given up. Tried MAP gas
> with an O2 sensor crow's foot tool and could only get it 1/8th turn.
> At least NAPA loans those tools, but 7/8" is too big, and rounded the
corners.
>
> If the treads are buggered, the shop can replace the cat with a pipe &
> bung, I don't need it.
>
> Stuart
>
> -----Original Message-----
> From: Karl Wolz [mailto:wolzphoto@q.com]
> Sent: Sunday, February 01, 2015 12:23 AM
> To: Stuart MacMillan
> Cc: vanagon@GERRY.VANAGON.COM
> Subject: Re: Removing stuck O2 sensor
>
> I use a Stilson wrench and a four foot heavy pipe as a cheater.
>
> Karl Wolz
> Sent from my electronic umbilicus
>
> > On Jan 31, 2015, at 11:59 AM, Stuart MacMillan
> > <stuartmacm@GMAIL.COM>
> wrote:
> >
> > Well, first attempts with a 22mm box wrench and heat have failed.
> > Should I break it off and use a regular 22mm socket?  Get a 7/8"
> > special O2 sensor socket, which is slightly larger, so I can put a
> > long bar on it? Take it
> to
> > a muffler shop?
> >
> >
> >
> > Other ideas?
> >
> >
> >
> > Thanks!
> >
> >
> >
> > Stuart
                                          =