Vanagon Syndrome -- Air Flow Meter fix
Transferred from archives
6/9/98 (4:22 PM)
[Note: This fix only applies to the digital FI systems called Digifant on the 2.1 liter engines. Do NOT post questions on pre-Digifat (Digijet or AFC) FI -- use the appropriate symptom topic.]
A number of driveability complaints on water-cooled Vanagons may be addressed by VW technical bulletin, No. 24-92-02, issued April 30, 1992.
We have heard of this update also fixing other symptoms not included in the technical bulletin, such as stalling, missing, hard starting, and loss of power. To see if your Vanagon has the update, remove luggage pad or mattress and open the top of the engine compartment. Attached to the air filter housing is an air flow meter, which then ducts the intake air to the FI distribution box in the center of the engine. On the rear of this air flow meter is an electrical harness that runs back to the brain box, disappearing in the right rear area (facing engine). If the fix has been installed, an approximately 9" long harness will have been inserted at the air flow meter. The original harness then plugs into the fix harness.
"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 hesitation or surging. In many cases, after turning off the engine and subsequent re-start 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 stability."
Remove electrical connector from air flow sensor. Install wire harness, Part No. 025 906 302, between main harness connector and air flow sensor connector.
Part numbers are for reference only. Always check with dealer for latest parts information. As of 6/1/98, it was still a good number with list price of $138. VW calls it a "transformer" and the technical bulletin does indicate there are "active components" in the harness, so the old manual's trouble shooting resistance of the circuit are no longer valid. They are given in the bulletin.
To test the new harness, continuity between ends readings should be: #1, 0 ohms; #2 greater than 1 megaohms; #3, 4 & 5, 0 ohms.
AFM - AMS (Hot Wire) Conversion?
Am considering buying the GoWesty engineered conversion of the AFM system to an Air Mass Sensor 'hot-wire' substitute.
Anyone have experience with this modification?