turbo conversion passes smog check
Sat, 31 May 2003 09:09:29 -0700 (PDT)
Heres an update on my little smog adventure for my
As you might recall I have a 90tq with the stock CIS-3
ignition and fuel powering a psuedo MC-2 with new
pistons but stock MC-1 cam and rebuilt head.
We have pretty strict smog rules here in California
and my car was due for its biennial check. I decided
to go the legal route and have it inspected and
referred by an official engine swap facility.
I went to a location that was at a local community
college. The inspection station was near the class
auto shop facilities and manned by what look like a
couple of student types with an older supervisor. The
student guys turned out to pretty proficient and
promptly did an entire engine bay inspection, asking
me a few questions here and there. After about 15
minutes they proclaimed my car "passed" the visual
part of the inspection and proceeded to run the
sniffer to check the acutal exhuast contents.
The car did not pass these tests. CO was way under the
specs (running lean) but the HC was in the gross
polluter category ! I was kindof bummed because I
thought the car was running great, had a new cat,
plugs, etc. It was tuned very carefully with respect
to timing and fuel mixture (at least I thought so).
I had 30 days to get my car in order and get a free
retest. A week later I went to a different smog tuning
place (where they allow unlimited testing). It took
about 3 trys but we were finally able to get the car
in spec. The big culprit was that the timing was too
advanced. When I set the timing to 0 TDC, the HC came
way down. A slight mixture richening, put things
nicely in place: CO was still very very low, and HC
was now under spec. Since my car is 4wd there is no
NOx portion to the test because they can't put the car
under load on the roller "dyno" (I guess). These guys
at the smog shop didn't really know what they were
dealing with (the engine bay looks real stock) and
proceeded to authorize my smog certificate right there
on the spot! I was good to go for another 2 years. But
I wanted my official CA engine swap sticker so back to
the referee station a week later.
The next time at the referee station they did the smog
portion of the test first....and I passed ! Numbers
similar the smog tuning place a week before. However,
these student guys (same guys) were pretty through on
the visual inspection and they found my little CIS DPR
test wires that I hadn't bothered to unhook (had been
doing mixture tweaks for a while and I also thought
they wouldn't do another visual inspection). Although
it wasn't affecting the operation of the fuel
delivery, they claimed it was and made a real big deal
about it (told me they could/should fail me right
there). I convinced them that we should just remove
the tester, plug in the regular connector and be done
with it. They insisted on a retest. Car passes of
course and I was on my way !
Now I have a little sticker on the door jamb that
states my conversion is officially approved. The whole
experience was not bad and I'm happy the car is legal.
I should have no problem when I go for a retest 2
years from now ! Now....I wonder what else I could do
to my car.....hn.
One other thing. I still notice the timing is bouncing
around somewhat. I set it to 0 BTC and it stays there
a while but then advances to 15 BTC (this is the
reason it failed smog the first time I believe).
Lately it has been doing less of this, maybe the
ignition computer is learning ?? Anyway 15 BTC is too
advanced, the engine pings under load on a warm day.
Any help the could shed some light on these timing
swings would be appreciated.
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