Ever drive down the road in your 86-91 VW Vanagon, all is well, stars are aligned, moon is in Venus (whatever that means), then all of the sudden: hiccup. At first you think it was a gust of wind, or a maybe you just drove over a raccoon. Then moments later: hiccup. The dreaded Vanagon highway hiccup syndrome has to do with the Digifant fuel injection system found on 1986-91 Vanagons (and some other VW vehicles of the same vintage). The culprit is the air flow meter (AFM). The AFM is the metal box attached to the air filter housing, that has an electrical fuel injection harness plug attached to it. This device does just what its name implies: it meters the air flowing into the engine, and send this info to the ECU which uses the data to determine how much fuel is required to achieve the optimal air/fuel ratio at any given moment.
The fine print: Even with a new or rebuilt air flow meter, these symptoms could return in as early as a year or two, or as little as twenty or thirty thousand miles. What was happening was the AFM would occasionally produce an erratic signal that the ECU could not interpret. During this moment of confusion, the ECU would simply cut spark and fuel to the engine, which produced a momentary "hiccup" in driveability. Sometimes the AFM would deliver unusable data so often that the vehicle would "buck" uncontrollably as the engine died and restarted multiple times per second, or simply cease to run at all. VW recognized this problem early on, and introduced a “signal filter” cable that would plug in between the air flow meter and fuel injection wiring harness*. This cable smoothed out the occasional erratic signal that the AFM would deliver to the ECU and nearly eliminated the problem entirely. However, even with it and a fresh air flow meter it was STILL not a for-sure, forever fix, as the design of the system is inherently less than perfect.
*Signal filter cable update: We have released our GoWesty-designed version of the signal filter cable—which costs almost 1/4 as much as the OEM version! Check it out here.
Note: The running issue with your vehicle may not be the air flow meter! Installing a GoWesty rebuilt unit may not make your vehicle run better, and it might make it run worse if the culprit is something else. Please be considerate to our sales staff. They are not technicians and cannot diagnose your problem via the telephone or email. We do have some very helpful articles you can read:
REMINDER: This is NOT a NEW part. These are rebuilt units that have been bench tested. We have had great success with these units—they are absolutely the best that money can buy. However, there is always the chance that a rebuilt unit will not solve you running issues as stated above.
This rebuilt unit is sold "exchange," which means that we need your original unit back for rebuilding. When we have received your unit and verified that it is rebuildable, we will issue a refund of this core charge. Cores missing a lid will be subject to a $20 core deduction.
Please call our customer service team for a return authorization number prior to shipping your core: (888) 469-3789.