1984 gti rabbit failed california smog

[murphysf]

Car Failed Smog

It failed NO at 15 & 25 mph (see below)

The car is a 1984 VW rabbit GTI BOSCH CIS mechanical fuel injection, with o2 sensor, NO EGR, the car has about 300k miles. I changed the cat converter in 2004 and the NO went to 0 it has increased over the years and now it is high and failed. I believe my hc and co are fine, what should I do? richen it up by adjusting the air/fuel mixture to get the NO to drop? or install a new cat, results are below

15mph RPM 1954
C02 14.59
O2 0.26

HC 28; Max 107 Ave 35
CO .16; Max .63 Ave .19

NO 1091; Max 845 Ave 564 FAILED

25mph RPM 2198
C02 14.90
O2 0.07

HC 24; Max 89 Ave 30
CO 0.10; Max .71 Ave .14

NO 726 ; Max 726 Ave 464 FAILED

[ny_fam]

There maybe something you can do to the tune.
http://webpages.charter.net/meduke/c...adjustment.htm has a how to that fixed a similar issue.

Could be as simple as taking the injectors off and soaking them in cleaner.

[armenhaz]

Sounds like you need a new catalytic converter.
Retarding the timing a bit usually lowers the NO