The MV slant here only applies to what I know is happening in
California, and only part of CA.
The boss bought a nice $45k smog machine that will be required for smog
tests after May1,
2002.
I had to attend several classes (above and beyond all the schooling
already required) in order to run it.
In short, its a computerized dyno made specially for smog tests, but
can be used for
torque (and then HP) calculations, as well as
driveability concerns (car does x at 35mph).
If you have a gas MV, newer than 1973, and
have it registered in one of the affected areas,
you'll be seeing it.
The dirtiest areas, like LA and Fresno and so
forth have had this test for a couple of years.
I live in the Central Valley, we got added to the
dyno list a few months back. (area of non-attainment means dirty air)
Some states have been doing what's called
IM 240 tests. My machine is capable of those, but CA only requires a
ASM 1525 test which is
cosiderably easier on car and operator.
If your MV is full-time 4wd, or above 8600 GVW or so, it won't go on
the dyno. The test will be the old two-speed-idle test except that
NOx can finally be tested.
In case you forgot, gas=powered vehicles spew lots of chemicals out.
We only look for
HCs, CO, and NOx on the test.
Believe it or not, clouds of blue oil smoke do not necesarily make you
fail the test. For the most part it is invisible to the smog machine.
Blue oil smoke clean-up is the job of the Air Quality Management
Districts (AQMD) to deal
with. People get ratted-out to them every day.
I know most folks don't keep reasons for
high emissions in their heads, so here goes:
HCs; caused by cool/ cold engines, over advanced timing, dead and
ramdom misses.
Can also be the result of extreme A/F problems
like too-rich or too-lean. However, CO would then be the main indicator.
CO: CO is only formed when there is extra
fuel hanging around that only partially gets
burned (combined with O2). Anything that makes a vehicle run rich is
the culprit. On older
vehicles this would be choke not opening, restricted air filter, fuel in
the oil (pcv sucks it in), contaminated evap charcoal cannister, high
carb float level, dirty air bleeds in carb. Once you add computer
(feed-back) controls to the
carb, the possible problems double or triple!
Don't forget idle mix, it can affect A/F throughout engine speed.
CO problems on fuel injected gas vehicles are: bad O2 sensor, bad,
wrong, mis or disconnected Manifold Absolute Pressure Sensor, coolant
sensor, bad or missing thermostat in cooling system( gotta be 190F or so
for this new stuff). Leaking injector.
NOx: Anything that causes cylinder temp to exceed a very high set temp.
So, very lean mixtures, over-advanced timing, inop or restricted Exhaust
Recirculation Valves (EGR)
higher than stock compression, carbon deposits
causing higher compression/pre-ignition. Whenever you hear PING when
you accel in a
gas-powered rig NOx is spewing out.
Higher than normal cooling system temps will
cause NOx as will disconnected cool-air inlet
hoses.
Dyno-Don
This archive was generated by hypermail 2b29 : Sun Jan 06 2002 - 22:26:52 PST