Try unplugging your o2 sensor. If it makes no difference then the problem is
most likely the cable/wire from the o2 sensor running to the ecm. I had a 84
and chased this problem for a while. I passed the tip along to a group I
used to belonged to and got replies of thanks from all over the world. The
wire is actually a coax cable and the insulation between the center
conductor and outer shield is deteriorating. Plus if it's got a "generic"
crimp on type connector that's a sure giveaway. It's running rich because
the ecm is not seeing voltage from the sensor and is adding fuel to raise
the voltage level. I used microphone cable from Radio Shack and replaced it
all from the ecm connector down to the o2 sensor. The system is actually
quite simple but a understanding of what's going on is necessary. You can
disconnect the connector to the o2 sensor and measure the voltage from it.
It should be around 1.5v as I remember measured with a digital meter.
JoBo
"Mystic" wrote in message
>I have tried to get smogged (california) an 85 Vanagon. Each repair
>facility I have taken it to has suggested replacing a different part from
>the fuel system. Does anyone here truly understand how this system works?
>
> I have replaced: Catalytic converter, O2 sensor, Coolant Sensor, Air Flow
> Meter, ECU (this actually made the vehicle stall at idle.) Another fix I
> was suggested was replace the fuel ingectors.
>
> My problem has been too much fuel in the exhaust. Does anyone truly know
> how this system works And how can I correctly find the problem? Smog check
> stations like to make guesses but are obviously ignorant of how this
> system works.
>
> MYSTIC >> Stay informed about: Smog suggestions 85 vanagon