Can a 12a run "too clean"? And why does it still smell?
This may sound a bit goofy, but I just picked up an 85 GSL with a 12A from CA with 39K original miles.
I had to get a smog test here in LV again. The car had always passed the CA tests with no issues. Funny thing, I had to have them classify it as a "four cylinder" engine at the DMV emissions lab because of reasons beyond my comprehension, so I guess the test was a bit tougher.
The smog-guy told me he hadn't seen one run this clean in a long time... at first I was pretty proud of my purchase... but later it made me think that it might be "starving" for some lubricating oil from the OMS.
Wouldn't it naturally run a little "dirty" since it's supposed to burn oil?
And,
There is definitely a noticeable smell when she fires up... like a two stroke... is this typical? (probably un-burnt fuel and not burnt oil...?) It's getting into the cabin pretty quickly.
Any thoughts would be much appreciated.
I had to get a smog test here in LV again. The car had always passed the CA tests with no issues. Funny thing, I had to have them classify it as a "four cylinder" engine at the DMV emissions lab because of reasons beyond my comprehension, so I guess the test was a bit tougher.
The smog-guy told me he hadn't seen one run this clean in a long time... at first I was pretty proud of my purchase... but later it made me think that it might be "starving" for some lubricating oil from the OMS.
Wouldn't it naturally run a little "dirty" since it's supposed to burn oil?

And,
There is definitely a noticeable smell when she fires up... like a two stroke... is this typical? (probably un-burnt fuel and not burnt oil...?) It's getting into the cabin pretty quickly.
Any thoughts would be much appreciated.
Joined: Feb 2001
Posts: 29,798
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From: London, Ontario, Canada
The carbureted 12As were actually quite well tuned, and when running correctly, are quite clean.
You can easily tell if it's too lean by pulling the plugs. If they are whitish and pitted, the engine is chronically lean. They should show a tan to dark tan colour if running correctly.
The FSM also has procedures to test the metering oil pump.
You can easily tell if it's too lean by pulling the plugs. If they are whitish and pitted, the engine is chronically lean. They should show a tan to dark tan colour if running correctly.
The FSM also has procedures to test the metering oil pump.
if you are getting exhaust fumes inside the cabin, the place to start would be the seals around the tail lights. They are well known to cause this issue once they begin deteriorating.
For information on tuning the carb, check out www.sterlingmetalworks.com Sterling is our resident expert on these babies, and knows them inside and out. There are many great writeups on his site.
Hope this helps...
.
For information on tuning the carb, check out www.sterlingmetalworks.com Sterling is our resident expert on these babies, and knows them inside and out. There are many great writeups on his site.
Hope this helps...
.
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alphawolff
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Nov 17, 2015 05:57 PM




