View Full Version : Wedge Riddle me this guys | TR8 SMOG test issue

06-06-2014, 09:26 AM
Hi guys - I could use some help from someone better caffeinated that I am on figuring out what is going on here. I took the 1980 ZS stock TR8 to my CA SMOG test, it failed CO levels narrowly. No problem, so I thought, I ordered up the ZS mixture tool from Moss, and 1/4 turn counter-clock wise to lean out the mixture and solved. Went and re-ran the test and the CO levels were far higher, almost 50% higher. Huh? How did that happen?

06-06-2014, 10:46 AM
I hope your choke(s) were not still on. I had a 79 coupe that went thru Maryland emissions that failed the first time, barely like in your case but the owner worked at a British car shop that had a Lucas super tuner and had to turn the carbs in 1/4 turn to lean and the timing was at TDC. It went back and passed BUT at night with a decent 10 degree drop in temperature it was not happy.

06-06-2014, 10:50 AM
I'm sure someone else will chime in shortly, But I think you made it richer turning that way. I always seem to turn them the wrong way. If I remember correctly, You are turning the carrier not the needle so clockwise should make it leaner.

06-06-2014, 11:17 AM
Hi George - manual seems to indicate that counter-clock wise is leaner - hmmm. The result sure seemed like it was turned the wrong way.

Wedge - she was warm so I think the choke wasn't an issue.

06-06-2014, 11:43 AM
I am wrong. counterclockwise should lean the carb. I still can't keep it strait in my head

06-06-2014, 11:45 AM
I am wrong. counterclockwise should lean the carb. I still can't keep it strait in my head

Me either George, me either...

06-07-2014, 01:12 AM
Here are some tips. Take it to a regular smog station, and ask to have a pre-smog test. As you suggest, CO is generally a condition of too rich.
Also, I have heard that it helps to change the oil before the test (less gasoline in the oil and the combustion camber), and also get it really, really hot by taking it on the freeway before the test. The pre-smog test is not hooked up to Sacramento (capital of CA for you non-natives), and will reduce the chances you are tagged as a gross polluter (very bad and expensive).
If you fail.....then try a tune-up.
cheers, and good luck...Scott in CA

06-07-2014, 11:50 AM
Had to put a new cat onto an MGB to get it to pass. The new cat dropped the numbers so far it failed the other way. So I gave it a quarter turn richer on the gas and it passed. From what I read, if your car ever blew a lot of oil out the tailpipe, the CAT is gone.


06-07-2014, 11:46 PM
Just WHY would you smog a car in California,if
you live in New York City?

- Doug

06-08-2014, 09:48 AM
Doug, long story but suffice to say car is in CA (as am I).

This would be so much easier if I had a sniffer, finding a local place to work with that actually understands a ZS is proving be to a challenge even when I explain it and give them a manual.

06-08-2014, 10:23 AM
There is a possibility some one put in richer needles.
Aside from that you can check a couple of things.
Make sure the temperature compensators are open when the engine is warm and for the test, open the idle mixture trim screws a couple of turns, advance the timing a few degrees and if you have an automatic choke..make sure it's not causing the rich mixture.
I wish I could say more about that choke, but I've never had to deal with a 'water choke', if that's what you have.

06-08-2014, 10:28 AM
Hi guys - good thoughts and I appreciate the help. Ken, she passed with these needles last go around so don't think that is it. It is possible she wasn't hot enough and the temp compensators or choke were in the loop. Will try getting her really hot and trying again. Apparently, from the last retest, I am OK at idle but the higher speed (more throttle) test is the issue.

06-08-2014, 10:41 AM
Just curious if California has any age exemptions for emissions inspection (if they do it must be older than 34 years since you have to pass with your 1980 TR8!)? Virginia only has emission testing requirements in 5 counties and associated cities and I don't live in one of those so we haven't had to deal with it but they do exempt anything older than 25 years from that testing as they qualify as antique motor vehicle.

"Gasoline powered passenger or property carrying vehicles with a model year that is more than 25 years old before January 1 of the current calendar year. As an example, vehicles with a model year of 1984 are exempt from emissions on or after January 1, 2009; vehicles with a model year of 1985 will be exempt from emissions on or after January 1, 2010. Vehicles 25 years old or older qualify as antique motor vehicles but are not required to display antique license plates to qualify for the emissions exemption. Although exempt from the emissions inspection, the $2 emissions fee is required when renewing these registrations."


06-08-2014, 05:03 PM
Here in CA, cars MY 1976 and onward have to pass smog.

Tom my only advice would be to make sure the car is fully warmed up. I had a 1990 Audi V8 that was a bear to register every two years; the Audi oracle recommended a very warm car, a couple of high speed runs on the freeway and then directly into the smog test lane, and sometimes, fresh gapped sparkplugs....

Best of luck!