Excessive Hydrocarbons are usually caused by the following:
        Incorrect fuel mixture, too rich is obvious, too lean causes a condition
known as a lean misfire. Leaky injector seal or any vacuum leak can cause a
single cylinder to be leaner than the rest also causing this problem. Some
lean miss is common on the Vanagon engine. A good Catalyst is needed to
clean this up.
        Ignition miss. This is obvious. Weak spark, no spark, all cause excessive
HC.
        Incorrect timing. Too far retarded, mixture does not burn in time. Too far
advanced, air supply at idle is reduced causing excessive HC and CO. Over
advanced timing will also raise the NOx levels for those getting the IM240
tests, (Dyno).
        Bad valves, guides, or other engine problems. Leaky exhaust valves
obviously cause excessive HC. So will bad guides as the valves won't seat
reliably. Any engine compression problem will show here. Check compression
and perform leak down test.

Hope this helps.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]On Behalf
Of Rick Berman
Sent: Tuesday, August 15, 2000 8:43 PM
To: vanagon@GERRY.VANAGON.COM
Subject: HELP HC to High at idle 525ppm should be about 70ppm

We cannot get the HC down at idle it  is now is about 500+.
We have tried all the usually stuff. We have a allen 4 gas
and a allen engine tester. Does anyone have some
suggestions.

Rick