View Single Post
  #35  
Old 08-23-2005, 08:55 AM
KATSCAN's Avatar
KATSCAN KATSCAN is offline
look to the cookie
 
Join Date: Aug 2005
Location: Pensacola/south carolina
Posts: 106
Thanks, my thermistor a little different looking ("Meat thermometer looking) but same mod. However, that being said, this is what I've learned to help optimize/analyze your particular car's ac system.;

1. Check ETS; make sure you know if it's working and what side of the spec
it's operating on.
2. Remove ETS from system, just pull it out of evaporator, do not unplug
and see the capability of your ac. Run Low air flow and take temp
reading of evaporator/center vent/etc. What you would really like to do is
get a "map" of the temperatures at different locations of the evap. That
would tell you if your temp sensor is in a cool spot or a hot spot relatively
speaking. I've have had the evaporator out of my car and have
seen how the core fins of the evaporator are bent from the act of
inserting/shoving the probe (ets meat thermometer). Certain flow
characteristics inherent to your particular evaporator and/or operating
system may have developed to create hot/cold spots. If your probe is in
a cold spot relative to the average evap temp....you won't get as cold as
you like. Likewise, if your ETS is itself at the top of it's specification.
Others who have no AC problems have been fortunate to have a correctly
spec'd thermistor and a "good location"; (or for that matter; may be in
a "hot spot"). I think that's why the MB specs are "wide". Some people
are just "lucky".
3. Take your new found data, postulate your best soln (conservative or
liberal), and try it.
4. You still need to be "lucky" to hit your mark first try. But you may be
close enough and should be cold enough now to live with it comfortably.
5. You may in fact "overshoot"
6. Some have set the cut off at -2 degrees*, others 0 degrees, still others
are fine with 3 degrees C. I can speculate that this variation is due to
the variability caused by limitations of sensors and location. Therefore,
the best soln is an informed one.
7. -2 degrees does not neccessarily mean you're operating at -2 degrees; it
will not cut the compressor out until the sensor reads -2degrees;
remember, you probe might be in a "cold spot"
__________________
JHaburay

1972 280se 4.5 "princess"
1986 2.3-16v first 100 (099) USA
Reply With Quote