How did you go about measuring the output at different
altitudes? Did you actually have wires running to some sort of ohmmeter
while in flight? Or did you use a pressure chamber? If pressure
(vacuum) chamber did you have a separate vacuum source on the manifold
lines? Otherwise, you would not have simulated altitude accurately.
David;
What I said:
“. . . even though the measured
output from the A and B sensors are the same when the unit is powered up (out of the plane) at different
altitudes (measured at 1400’ and 5300’).”
was not very clear. The output
measured at Ramona (1400’) was consistent; and that measured at Boulder, CO (5300’) was also
– within less than a milivolt. So this would suggest that the
output response is the same, or IOW, at WOT, at different altitudes, A and B should be the same. The sensor on A also
appeared to be in fine shape in all respects. It is true that this is not
the same as pulling a vacuum on the ports to say, 20” Hg with both
at the same altitude. That test seemed more difficult than buying a new
sensor. I should know next week whether that solves the problem.
In
replacing the sensor, and further studying the circuit, my son says “ I installed the
new MAP sensor, and added a ground lead from the sensor to the processor (I
think the lack of a good ground return
was the source of the RF and other
problems). He has
remarked before that his opinion is that the ground circuits on the board are
not particularly resistant to RF issues.