dodsond
New Member
- Joined
- Aug 9, 2006
- Messages
- 76
I have a UMA 1B3 probe (Type 10). I recently replaced the 1 wire Dynon probe with this 2 wire probe because the readings were erratic during engine operation. This probe has very steady readings but I firmly believe the calibration file in the D-120 is not correct. I have very carefully checked the ground, and the behavior is the same whether the engine is running or not. A thermistor failure is unlikely, that would just give an open or short. My system shows a change in slope. I know of no material failure that would cause that behavior but I don't know of course what goes on inside the D-120.
Here are my readings, gathered quite carefully and repeatable:
Fluid Temp D-120 Indication
45 120
50 117
55 113
60 109
65 105
70 101
75 99
80 98
85 99
90 100
95 101
100 103
105 107
110 112
120 122
130 133
140 144
150 154
160 164
170 175
180 186
190 196
196 200
As you can see, the readings are quite satisfactory above 100 degrees F but below that the slope is reversed.
What can cause that behavior?
Here are my readings, gathered quite carefully and repeatable:
Fluid Temp D-120 Indication
45 120
50 117
55 113
60 109
65 105
70 101
75 99
80 98
85 99
90 100
95 101
100 103
105 107
110 112
120 122
130 133
140 144
150 154
160 164
170 175
180 186
190 196
196 200
As you can see, the readings are quite satisfactory above 100 degrees F but below that the slope is reversed.
What can cause that behavior?