Help on EGR Cleaning

[welin70]

Hello,

I bought an 86 GT-S Coupe not long ago. However, it barely FAILED CA smog test. NOx is slightly higher than the max at 25 mph (1174 on 1038 Max). From what I read though the forum, it seems that the problems might be either EGR system and/or O2 sensor.

I replaced the oxygen sensor, airfilter, and oil. I ran a tank of gas with fuel system cleaner. Clean the EGR vacuum modulator filter. I asked about how to remove the EGR valve for cleaning here, but I didn't get any response.

Since it was barely failed, I thought what I did would be enough to pass the smog test. The resutls of the second smog test is very puzzling. The NOx at 25 mph passed easily (584), but all other numbers went up, HC and CO failing both at 15 mph and 25 mph. Below are the numbers:

Spd Max 1st 2nd
HC 15 152 90 227
25 127 114 167
CO 15 0.91 0.24 1.09
25 0.71 0.38 0.93
NO 15 1208 967 1169
25 1038 1174 584

I am totally lost. Can anybody tell me what happened? Thanks!
WT

[welin70]

Tried the 2nd smog test and failed again. Updated the post for new questions. Please help!

WT