Greetings and Salutations;
Here is a brief synopsis of actions I took to get my truck to pass. I did
not use any stop-gap solutions but strove to pass legally.
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First testing:
                        Reading         Standard
Hydrocarbons (ppm)      266 ppm         220ppm
Carbon monoxide(%)      0.40            1.2
Carbon dioxide(%)       11.8
Engine RPM at reading   894
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Where upon I proceeded to:
1> poll the list for suggestions.
2> changed the oil.
3> Set the timing properly. I had it slightly advanced to improve
   performance.*
4> Checked compression(125,125,125,139). Noticed #4 plug looked
   wet,appeared to be a small amount of oil.
5>Attempted AFM calibration using O2 sensor and adjusting spring. I
  felt positive results were achieved.
6>Ran a tankful of gas with Injector cleaner through.
7>Drove for 15 minutes at 65+mph to testing station to warm up
  engine.
Second test(about a month after first) the readings were about the same!
HC still failed.
Back to the drawing board.

A> Purchased K&N air filter.
B> Replaced both fuel filters.
C> Fuel rail hoses looked bad so they were replaced.
D> Switched to Platinum plugs. Reasoning here was better firing if     #4
was oil fouling.
E> Set idle stop as per Bentley.
E(1)> Re-did AFM calibration.
F> Reset idle. Ended up turning Idle Set screw almost all the way
   in. This took several turns. Made up the balance of idle air
   with the Air Bypass Valve(aka idle stabilizer valve)
   adjustment.**
F(1)Test ABVs current as per Bentely=430mv.
G> Drove around for about 40 minutes before testing.
H> Went to a different tester.
I> First customer of the day so I was tested immediately after
   machine's daily calibration.
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Third testing:
                        Reading         Standard
Hydrocarbons (ppm)      99 ppm          220ppm
Carbon monoxide(%)      0.04            1.2
Carbon dioxide(%)       7.9
Engine RPM at reading   883
--------------------------------------------------------

HC was less than half and CO2 improved by a factor of 10!! I wish I could
point to a single action that did the most good.

*The performance now, with near factory settings, seems as good as ever.
 **I do not recommend "experimenting" with this adjustment, I think that
is what fouled things up. Right before this I had a very rough cold idle.
My theory is the engine has two sources for it's idle air. The throttle
body and the ABV. I believe this ratio got way off. I still had the
correct volume for good hot idle but there was insufficient going through
the ABV to modulate a good cold idle. There is no procedure in the
Bentley, I learned about it on the list and fooled with it to try and fix
a problem several months ago.

Drive Safely & Good Luck
Ken Lewis<Kernersville,NC>86 VW crewcab;60 T-5 Coupe

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