Maybe I didn't do enough homework but maybe you guys will forgive me.

GFs 87 4Runner with 4 cyclinder failed emissions. I took through emissions back in late December and it passed. For various reasons it had to be redone today and it failed.

It is failing HC in PPM at the Loaded Test.

The standard is 220 and the reading was 225.

What should I check? The engine runs fine.

 

Give it a good tune up. Use factory plugs and air filter.

 

BTW it is a 22RE.

Changed from Bosch plugs to NGK. The rotor looked rough so swapped that. The air filter, distributor cap, wires all looked good. The old Bosch plug colors looked tan and were so new still I could see white ceramic on half of the tip.

It failed again.

Went to mechanic #1 he says Cat Coverter.

Mechanic #2 looked at it and said to take it to Motor Vehicle Testing site X. It passed with margin. Loaded HC reading was like 155 and limit is like 200. Other Testing site had measured 205 so it failed.

End of story. Morale of the story is that Testing Sites differ. Ask a knowledgeable local mechanic. I've heard of Blue Sky additives and adjusting timing etc to pass emissions too.

 

Its been awhile but i had a similar problem with my 85 22re. Took it to a mechanic and he said it passed on his scan but just to make sure. I retarded the timing (i think) made it start real easy but zero power. nursed it there from a near by parking lot and passed with flying colors. had to put in 4low to get it up the hill in to the bay. but passed non the less.
But yes all the emissions places seem to be different. my new house is very close to the loosest one in the state from what I understand.