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Date:         Thu, 11 Aug 2011 22:20:15 -0400
Reply-To:     Shawn Luft <shawnluft@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Shawn Luft <shawnluft@HOTMAIL.COM>
Subject:      Re: Help! Hesitation on the road!
Comments: To: david_vickery@yahoo.com
In-Reply-To:  <1313114737.32264.YahooMailClassic@web160610.mail.bf1.yahoo.com>
Content-Type: text/plain; charset="iso-8859-1"

I had a hesitation problem once that I fixed by changing an electric connection to the fuel injectors.Took a used connector from an `86 Jetta and it was the same fit.

Good luck

> Date: Thu, 11 Aug 2011 19:05:37 -0700 > From: david_vickery@YAHOO.COM > Subject: Re: Help! Hesitation on the road! > To: vanagon@GERRY.VANAGON.COM > > I appreciate you (Dennis) taking the time to explain this. I didn't understand how it could be the problem if disconnecting the o2 sensor caused the same symptoms. Since my problem isn't fixed and I am looking for solutions, I just found this document that I think is great too. It mostly focuses on the AFM but has a lot of good info and the description of the problem sounds exactly like what I have been experiencing. > > www.vanagonauts.com/files/FIxSystemxAFMxproblemsxxxfix.rtf > > --- On Wed, 8/10/11, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote: > > > From: Dennis Haynes <d23haynes57@HOTMAIL.COM> > > Subject: Re: Help! Hesitation on the road! > > To: vanagon@GERRY.VANAGON.COM > > Date: Wednesday, August 10, 2011, 4:39 PM > > That harness has limited success in > > solving the problem and part of that > > solution is the effect of modifying the AFM output. VW was > > wrong. > > > > The O2 sensor circuit is the only circuit that actually > > calibrates to a > > signal, a real voltage, not a resistance change. When the > > signal is weak or > > there is a noise or ground problem the ECU will continue to > > richen the > > mixture until it sees that signal. A bad ground reference > > or a shorted input > > lead will even override the effect of disconnecting the > > sensor. The ground > > reference is the brown wire that travels in the distributor > > harness. Often > > it is connected to a screw at the base of the oil breather. > > The plastic does > > not make a good connection. Move it and if the wire in the > > crimp is brown > > replace a crimp ring terminal. For wire testing do the > > following: > > > > Disconnect the O2 sensor and peel back the outer wire > > sheath to expose the > > outer shielding. Yes this is a coaxial wire. > > > > Key on-Engine off, with a sensitive or digital voltmeter > > measure between the > > outer shield and a good reference point on the chassis. > > Should be real close > > to 0 volts. > > Measure from center (signal) wire to same reference. Should > > be .5 to .6 > > volts. > > Measure from center to shield. Should be same as center to > > ground. > > > > Any stray voltage on that shield gets added to the voltage > > setting the O2 > > sensor circuit is looking for. So let's say you see .25 > > volt on the shield. > > The ECU will not reverse and lean out the mixture until the > > O2 sensor puts > > out ~1.0 volt. Since normal regulation is somewhere between > > .2 and .8 you > > can see where this can mess things up. > > > > Dennis > > > > -----Original Message----- > > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] > > On Behalf Of > > george jannini > > Sent: Wednesday, August 10, 2011 4:16 PM > > To: vanagon@GERRY.VANAGON.COM > > Subject: Re: Help! Hesitation on the road! > > > > I Googled... > > > > VW technical service bulletins regarding driveability > > complaints read as > > follows- The first details problems with Digifant engines > > and the second one > > supercedes the first, acknowledging problems with Digijet > > Waterboxers as > > well. > > > > --- Begin quote --- > > > > Technical Bulletin Group: 24 Number: 92-01 Date: February > > 29, 1992 > > Subject: Vanagon Intermittent Misfire Model(s): All Vanagon > > Digifant Fuel > > Injection Engines > > > > CONDITION After driving for 1/2 to 2 hours at a constant > > speed, vehicle > > experiences lack of power, cuts-out or stalls, often > > accompanied by bucking > > or jerking of the vehicle. In ALL cases, the vehicle will > > restart > > immediately. > > > > This symptom may not re-occur for several weeks/months. > > Inspection by the > > dealer results in nothing conclusive. Some air-flow meters > > may experience a > > vibration resonance of the metering potentiometer wiper > > during extended > > constant driving. This resonance causes the air-flow meter > > to supply an > > intermittent signal to the Digifant ECU. The ECU will then > > default to a > > "no-load" condition and reduce the injection time. > > > > SERVICE Harness, Part No. 025 906 302, is available to > > resolve this > > condition. * remove electrical connector from air flow > > sensor (see Figure > > 24-174) * install converter assembly, Part No. 025 906 302, > > between harness > > and air flow sensor NOTE If customer complaints persist > > after performing the > > above repair, contact your Zone Product Support Specialist > > (TSM in Canada) > > > > ____________________________________________________ > > > > > > Technical Bulletin Group: 24 Number: 92-02 Date: April 30, > > 1992 > > Subject: Vanagon Drivability Complaints Model(s): All Water > > Cooled Engine > > Vanagons SUPERCEDES TECHNICAL BULLETIN 24-92-01 (February > > 29, > > 1992) > > > > CONDITION After driving for an extended period of time at > > a constant speed, > > the vehicle may, on occasion, experience a deterioration of > > performance > > which may be accompanied by a hesitation or surging. In > > many cases, after > > turning off the engine and subsequent re-start or without > > having taken any > > action, the symptoms disappear. These symptoms may not > > recur for several > > weeks or months. > > > > SERVICE To resolve this condition, wire harness Part No. > > 025 906 302, > > should be installed. This harness provides improved signal > > voltage > > stabilization. * remove electrical connector from air flow > > sensor * install > > wire harness, Part No. 025 906 302, between main harness > > connection and air > > flow sensor connection. > > > > --- End quote --- > >


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