Benzmac
Further to my recent posting here is some
background information. I have owned my 35k
mile 1985 euro 16v for 13 years and it has
been well maintained with OEM parts. It does
not have a cat, o2 sensor, frequency valve,
etc. In the past it has always passed the old
4 gas emission test in Illinois. The only
change I would make was to turn the EZL plug
(located next to the battery-2 wires in-1
brown, ground-ok, 1 black/yellow-approx.-6
volts out) counter-clockwise 2 positions.
Power would decrease dramatically-similar to
retarded timing. Recently I made this same
adjustment and it had no effect on performance-and the car failed the new IM240
dyno emission test. It passes co and hc at
higher rpm but fails both at idle-test results are a composite of the two. I replaced the EZL plug (the resistors tested
the same however) but adjusting the position
as previously has no effect on performance or emissions. The wires from the EZL
(referred to as a Reference Resister) lead
into the ECU. Am I missing something or is
this an excercise in futility?
Sorry for the lengthy diatribe, but your advice would be greatly appreciated!
Regards,
Mike C

What you were doing was changing the timing advance curve, so the timing was the only item affected. On "euro" cars there is provision for poor quality fuel. Sounds like you will need to have fuel system adjusted & or modified to pass, possibly even a catalyst.

------------------
MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS DEALER M.B. Shopforeman
190E 2.3 ITS RACECAR
1986 190E 16V