Charlie Slayman wrote:
Date: Mon, 7 Feb 2011 00:21:15 -0800
From: Charles Slayman <[email protected]>
Subject: [alfa] Marginally High CO Emission from L-Jet Spider
Dear Alfisti,
I just failed the bi-annual California emissions test on my '89 L-Jet
Spider for marginally high CO at 25mph. Here are the results:
2801 @15mph, Max CO Allowed 0.78%, Measured CO 0.78% PASS
2870 @25mph, Max CO Allowed 0.66%, Measured CO 0.78% FAIL
The other tests (HC, NOx) passed and actually get better with speed, so the
catalytic convertor is working. This looks like a problem with the mixture
running rich. The O2 sensor is working and the temperature sensors are
working (so the L-Jet is not running rich intentionally because it thinks
the engine is cold or the O2 sensor is dead and defaulting to a rich
condition).
Have any of you experienced a rich condition on an L-Jet that was not due to
a dead O2 or temperature sensor?
Perhaps the AFM spring is getting tired and telling the ECU to stuff too
much fuel into the engine? Tightening up the AFM air flow door flap
spring should fix your rich problem. We had an '86 LJet Spider for which
someone had apparently tightened up the spring too much and it was
running chronically lean. We loosened up the spring and fixed that
problem. You should be able to lean up your engine adequately. I'm
guessing the spring is losing temper and just a tooth or two of
tightening up would fix it. Easy fix. Look up the LJet pages on Greg
Gordon's site for any details you might need about accessing the spring.
Michael
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