Scott,
Stu Brennan's temp and fuel gauge data given in Mark Olsen's Tech Tips Web
page,
http://www.corpdemo.com/tiger/techtips/gageohms.html
is very helpful in diagnosing the accuracy of your gauges. At 200F (93.3C),
the sender should be about 52 Ohms, and at 215F (101.67C) it should be
about 40 Ohms. If you can find resistors of these values and substitute
them for your sending unit; i.e., provide these resistance values to
ground, the gauge should read the corresponding temperatures. You can use
other resistance values in this range and interpolate the temperatures
accordingly from Stu's data points. If the gauge reads more-or-less
correctly, then you need to check the sending unit resistance versus
temperature. For this you need an Ohmmeter and thermometer. Measure the
sender resistance at one or more measured temperatures and compare with
Stu's numbers and your particular gauge's calibration. Now, you really only
need to follow this procedure if your gauge is reading incorrectly and need
to determine whether it's the sending unit, the gauge itself, or both. So,
it's probably best to just start by comparing thermometer and gauge temps
and see if they agree. If not, follow the procedure above to diagnose the
problem. If your lucky, maybe your gauge is reading a bit high. If both the
temperature and fuel gauges are off, check the voltage regulator (should be
10V).
Good luck,
Bob
At 10:32 PM 6/28/99 +0000, netscott@earthlink.net wrote:
>has anyone had this problem. it seems that as my motor get hotter the
>water temp. gauge reads hotter. that is to say that when i first start
>my motor my electric fan will go on at 200, after some time the fan goes
>on when the gauge reads about 215. is it possible that the resistance in
>the wire from the sending unit is changing with heat and is causing this
>difference.(i have replaced the sending unit and it did not help)
>
>scott
>B9472628
Robert L. Palmer
UCSD, Dept. of AMES
619-822-1037 (o)
760-599-9927 (h)
rpalmer@ucsd.edu
rpalmer@cts.com
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