also do a compression check and you must have no leaks on exhaust
system before the O2 sensor. also it is best to just go ahead and
replace all vacuum lines and hoses since the age of the bus the vacuum
lines are cracked and brittle. c-ya Jonce

>Vacumn lines, temp sensors.
>
>I had the black smoke rough idle problem. Found the hose on top of the
>engine between the crankcase vent and the AFM on the ol' 2.1L WBX  was
>rotten and had a hole in the underside where it couldn't be seen.
>Replaced the hose and the roughness and black smoke problem disappeared.
>
>John Rodgers
>88 GL Driver
>
>Mark Seifert wrote:
>
>> Ok, so my vanagon is running rich, and I was outside fooling with it
>> today
>> to see if I could figure it out. In the mornings, when I start it up,
>> there
>> is a brief puff of BLACK smoke, and the engine won't idle. I have to
>> keep my
>> foot on the pedal to keep it alive. After a few minutes, it seems to run
>> pretty normal. But, my plugs have kind of a lot of cabon build-up, and my
>> gas mileage is not so great. I'm pretty sure the motor is running
>> rich, and
>> that this cold-start problem is related somehow. I adjusted the airflow
>> meter, checked the o2 sensor, blah, blah, blah...Can't figure it out.
>>
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