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1988 Volkswagen Vanagon

Engine: 2.1 L / 4 cyl / Gas / OHV Fuel: Fuel Injection / Bosch AFC EFI Ignition: Distributor-Breakerless / Hall Effect Distributor Trans: 3-speed Automatic Transaxle Mileage: 140,000 mi Emissions: Federal VIN: WV2YB025XJH

Symptoms: Excessive Emissions, Poor Idle Quality Occurs: Hot, Idle

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Hello Again:

MOD is wrong again. Pin 20 on the ECM should be grounded. We believe that it has something to do with the O2 sensor service reminder light. Once we grounded the gray/white wire the system went into closed loop and the CO% reading came crushing down. It even passed the Ontario Drive Clean ASM test beautifully.

Several replies confirmed that these engines idle on the wobbly side and pulse width of 3 msec+ at idle is quite normal.

Thanks so much to all those who responded.

Eli

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Hello VW Experts:

We've got an 88 Vanagon that's proving to be a pain. It was sent to us from another shop after spending considerable time on this beauty.

The complaint is that after a few minutes following a cold start, it starts to run rich, spewing black smoke along with a shaky idle. This seems to be a basic Bosch AFC port injection system. We followed the diagnostic charts, checking all powers/grounds/sensors etc right at the ECM. Everything is within spec. Fuel pressure is a steady 30 PSI at idle. The O2 sensor has been replaced and is pegged at 1 volt. The enrichment/idle switches are functioning. The coolant sensor has been replaced and another ECM was apparently tried without success. There are no vacuum leaks and ignition timing is right on. On a cylinder balance test, all cylinders seem to do something. The only sensor in doubt is the air-flow. Playing with the CO adjusting screw makes a difference (all the way to a stall) but not improve the rich condition. One strange item: The flap of the airflow meter vibrates at idle (intake pulsations?) The injector pulse-width at idle is about 4 msec. which seems high. The injectors hold pressure with the engine off.

Any ideas will be appreciated

Eli

Eli Melnick melnick@home.com Owner/Manager Start Auto Electric Ltd. Toronto, Ontario, Canada

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