Quote:
Originally Posted by captainchris
Hi WD8CDH,
The sedan fuel sender is 12 7/8" long (to the nearest 1/8"), including the small plastic nut at the bottom. (Not visible in the picture.)
The wagon fuel sender is currently in use, so I can't get an exact measurement. Here's another picture. It looks like a little over 7 1/2", plus some accounting for the nut.
As for the threads, I'm not familiar with the "36mm x 1.50 pitch" notation, so I measured the outside diameter of the threads of the sedan fuel sender and got 44mm. (+/- 1mm as I don't have a proper caliper.)
As for resistance measurements, these two fuel senders were part of an experiment. The wires in my wagon fuel sender were shot, so I used this sedan fuel sender as an organ donor. My assumption was that the wires had the same rating in terms of ohms/unit length, and the wagon compensated for the difference in length using the 325-ohm resistor in the head of the fuel sender. (Pics attached.)
The result is that my fuel guage now deflects between half and full. (Half equalling empty.) At least my reserve light now works. I think I will have to fool with the resistor to get an accurate deflection.
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Hi Captainchris,
Thanks for the info. Good point about the invisible plastic nut.
It looks like the threads of the sender are larger than the threads of the fuel pickup screen on the bottom of the tank.
The wagon unit would have to have finer wire since it needs the same resistance for it's TOTAL length. If you know the length from float contacts up to the top of the sender, I can calculate the gauge of resistance wire that you would need. If the float size is the same on both the wagon and sedan senders, I could estamate the wagon dimensions from the sedan dimensions.
The resistor will not help you on the wagon. Removing it compleatly will maybe move the needle about 1/4 of a needle width closer toward empty.
The resistor is just for the manufacturer (VDO) to make fine calibration of the empty reading of the about 50 different length senders that they make without using 50 different diameters of resistance wire.
One of VDO's most common OEM fuel gauge meter movements requires about 90 ohms for an empty reading so all of their "Tube Type" senders have similar resistance at empty.
Do you have a picture of the reserve contact end of the sender?
Thanks,
Ron