~ my comments interspaced below ~
----- Original Message -----
From: "alfa-digest"
From: Robert Lorenzini
The temp sensor also affects rich/lean. Raising the resistance = richer.
For sure double check the thermostat/temp sensors. Don't trust the dash
gauge. A cheap non-contact thermometer is a fun tool to own.
IF you wanted, you could pull the fuel rail and injectors free of the
inlet ports and activate the fuel pump, then check directly whether the
injectors are leaky when closed. Just a thought.
From: Charles Slayman
I like your idea of pulling the injector rail and looking for leaks with
the
system energized! That fits my criteria of simple/inexpensive tests.
Thanks,
Charlie
An easier (but less exacting) check is to remove the spark plugs & turn the
engine until you can see the intake valve open (peeking in via the spark
plug hole). Then cycle the key on-off-on-off to pressurize the fuel rail (or
'hot wire' the fuel pumps) while looking/sniffing for evidence of raw fuel
from that cylinder. It might reveal a badly leaking injector but would not
be able to prove if they were leaking just a little bit.
I suspect a slightly leaking fuel injector would not affect the higher speed
emissions results as much as it would affect idle emissions.
If you suspect the spring tension of the AFM is too weak - leading to an
over-rich condition - you can remove the cover over the AFM (it was glued on
at the factory but can be carefully removed by cutting through the glue) and
watch the arm inside that is connected to the flap. With the engine running
at a steady speed/load the flap should be quite steady. If the spring
tension is weak the flap will tend to oscilate in the air flow. It was
common 'back in the day' to loosen that spring in an attempt to richen the
mixture for more performance. (It rarely helped and usually just made things
worse.) If you decide to 'adjust' the spring tension, the goal is just
enough tension to make the flap ride 'steady in the wind'.
Where are you located? It might be easier to borrow a known good AFM for
testing (before fiddling with yours). I have a spare if you'd like to borrow
it.
Eric Russell
Mebane, NC
http://home.mebtel.net/~ejrussell
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