I removed the tank and tested the fuel sender with the omhs meter:
its bad :(
I took the sender part and found the wire broken.
These units run between $80-$120 new - so I thought I would try to rebuild mine - as its not very difficult - as long as its just the wire. I measured a 1 foot length and it has a resistance of 60 ohms (I assume thats how you figure out the ohms per foot)
I found this site to figure out the gauge of wire I needed:
Check under the 'Ohms per Foot Alloy Match locator'
But after doing many searches I can't find anyone who makes 39.5 awg
But I did find a company that does build 39 awg - which might be close enough for the gauge to work
....
But - before I ordered the wire - I thought I would try to find a used one. It seems a lot of buses where getting parted out this winter. I found a used fuel sender for $20 shipped!
But after I got the used fuel sending unit - it also didn't have any ohms :(
I took it apart and found it was very dirty inside where the wire connects to the top. So I tried cleaning with some green cleaner:
but the contacts between the inside wire and the ground just didn't get cleaned enough:
Finally I just removed that wire and rebuild the one that had a broken wire by un-soldering the old one and carefully re-soldering the replacement wire.
It now reads something like 80 ohms when empty (float at the bottom)
I didn't hook to the gas gauge yet - I'll check that once I get everything back together.
Here are a few links that will help understand the VW Fuel sending unit:
VW Fuel Sender Information:
Tub sender was for 68 to 1/73
Swing arm sender - 2/73-79 (swing arm uses a vibrator on the back of cluster)
http://www.nls.net/mp/volks/htm/fuel_ga.htm
http://www.midsouthvw.com/TechTips/tech_tip_FuelGauge.htm
Rebuild Swing arm sender:
http://www.thesamba.com/vw/forum/viewtopic.php?p=4112584#4112584
