Temp 2 and temp gauge sensor ohm readings

[vanis13]

What should the ohm/temp readings be for the gauge sensor?


I did find the ohm readings for the Temp 2 (ecu) sensor in Bently 24.45

Ordered some new sensors to have on hand when opening the Tstat housing and want to check them before installing. Also want to check the old ones.

chasing cause of 12mpg https://www.thesamba.com/vw/forum/viewtopic.php?t=771530

Also the gauge is barely in the LED even when second stage fan goes on so want to verify its sending proper data before I chase the gauge calibration.

This is on a 1991 2.1
_________________
83.5 Westy with Subaru 2.5, 4 spd manual, center seat, COLD A/C on 134a!, Winter camp heated with an Espar B4 gasoline furnace

www.SuperVanagon.com - some stuff I make

[ZsZ]

They should be the same sensor - and AFAIK all '80s VW sensors had the same diagram referenced.
They are making resistance to ground, so bad ground connections make false readings for the ECU.
_________________
Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008

[vanis13]

[ZsZ]

[ZsZ]

found this old topic:
https://www.thesamba.com/vw/forum/viewtopic.php?p=8085137

black gauge sensor values:
I assume the temp is in F

EDIT:
I think the measured values are in kOhms as the gauge testing values are 200-33 Ohms:
https://www.thesamba.com/vw/forum/viewtopic.php?t=464113&highlight=temp+gauge
_________________
Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008

[Geato]

Based on the Rt of 2K @ 25C and the Beta of the thermistor used, here is a table of R v T where R is in ohms and T is degrees C. Of course, this is based on the ideal thermistor but as we all know, there is a manufacturing tolerance. Sorry about the significant figures

Temperature Resistance
0.000 5,600.00
1.000 5,358.67
2.000 5,129.04
3.000 4,910.48
4.000 4,702.41
5.000 4,504.27
6.000 4,315.53
7.000 4,135.71
8.000 3,964.35
9.000 3,800.99
10.000 3,645.23
11.000 3,496.69
12.000 3,354.98
13.000 3,219.76
14.000 3,090.70
15.000 2,967.50
16.000 2,849.86
17.000 2,737.49
18.000 2,630.15
19.000 2,527.57
20.000 2,429.54
21.000 2,335.81
22.000 2,246.19
23.000 2,160.47
24.000 2,078.47
25.000 2,000.00
26.000 1,924.90
27.000 1,853.01
28.000 1,784.17
29.000 1,718.25
30.000 1,655.10
31.000 1,594.59
32.000 1,536.60
33.000 1,481.02
34.000 1,427.74
35.000 1,376.64
36.000 1,327.63
37.000 1,280.61
38.000 1,235.49
39.000 1,192.20
40.000 1,150.64
41.000 1,110.73
42.000 1,072.41
43.000 1,035.61
44.000 1,000.25
45.000 966.28
46.000 933.63
47.000 902.25
48.000 872.07
49.000 843.06
50.000 815.16
51.000 788.31
52.000 762.49
53.000 737.63
54.000 713.71
55.000 690.69
56.000 668.52
57.000 647.17
58.000 626.60
59.000 606.79
60.000 587.70
61.000 569.31
62.000 551.58
63.000 534.49
64.000 518.01
65.000 502.12
66.000 486.80
67.000 472.01
68.000 457.75
69.000 443.98
70.000 430.70
71.000 417.87
72.000 405.49
73.000 393.54
74.000 381.99
75.000 370.84
76.000 360.07
77.000 349.66
78.000 339.60
79.000 329.88
80.000 320.48
81.000 311.39
82.000 302.61
83.000 294.11
84.000 285.89
85.000 277.94
86.000 270.25
87.000 262.81
88.000 255.60
89.000 248.63
90.000 241.88
91.000 235.34
92.000 229.02
93.000 222.89
94.000 216.95
95.000 211.20
96.000 205.62
97.000 200.22
98.000 194.99
99.000 189.92
100.000 185.00

[Geato]

If you want test your gauge you can probably pull out some useful information from my handwritten notes. I have fuel gauge info too. Note: R represents Ohms.

notes.

[oceanair]

Know that the two senders are totally independent. The ECU has no idea of the temp1 on your dash and what it is doing. It only reads Temp2.

Definitely get yours on the dash sorted, it's very important, but the ECU is not using it and it's not directly affecting your MPG.
_________________
84 Vanagon Pop Top Conversion from Tin Top, 1970 Ghia - all sweet rides! Love em!
Previous: Green 72 Tin Top, White 72 Westy, Blue 64 Beetle, Yellow 71 Squareback, 2014 Jetta TDI Wagon - wish I could have them all back!

[crazyvwvanman]

The dash temp gauge sensor has no assigned number.

Temp1 is intake air temp sensor for fuel injection. (inside AFM, aircooled and wbx)
Temp2 is engine temp sensor for fuel injection(aircooled cyl head, wbx in thermostat housing)


Here you can see the Temp1 and Temp2 on a diagram for aircooled.

Mark

[vanis13]

Started some temp testing last night. More difficult than expected due to different sensing speeds by different sensors. May have to coorelate data to stable temperatures of: ice water, ambient, and boiling water.

It would be nice to get some other stable temp points where every sensor had time to stabilize to it. If you have any ideas, please send them.

_________________
83.5 Westy with Subaru 2.5, 4 spd manual, center seat, COLD A/C on 134a!, Winter camp heated with an Espar B4 gasoline furnace

www.SuperVanagon.com - some stuff I make

[Geato]

Best way to get a stable bath is to get one of those cheap styrofoam coolers and just use different ratios of hot / cold water. Larger coolers are better for longer term stability. Poke some holes in the lid for the wires.

Also, it is best to fully submerge the sensors and you can do this by putting them into a freezer bag. Keep the ziploc seal above the water line though as it will never seal around the wires.

[Geato]

I should also add, it is best to have a slow speed stirrer to keep the water from stratifying.