For my 1955, I measured resistance of the removed sending unit at its extremes-full and empty-float up and float down. Float down-around 75 Ohms, float up-around 10 Ohms. Then I built a variable resistor from Radio Shack parts, connected the variable resistor to the disconnected sender unit leads in the trunk, adjusted the resistor to make the dash gauge read empty, 1/2 and full, measuring the resistance at each point. The values were similar, so the sender was installed and sort of works. I have not chosen to make multiple removals and installations to adjust the wire float to make sure float down is truly empty. The variance in resistance as the float arm is moved should be smooth to assure good contact of the slider on the resistance wire. I had my original sender rebuilt as it had a broken fine resistor wire. The rebuilder installed a new resistor coil and slider, but they were of different dimensions and it doesn't work very well. I seem to get a nervous gas gauge needle, even when sitting still with the engine running. Possibly due to voltage regulator variance. So, the gauge sorta works, but I use the trip odometer as a primary indicator of when its time to fill up. With all the cars I've owned and driven, I've never seen any other than a 1961 Karmann Ghia VW that had a gas gauge that was anywhere near accurate an linear throughout the range. Irregular shaped tanks, crude design of senders and lack of a calibration system preclude accurate remaining fuel indication. I hope the aircraft industry does better with their fuel measuring systems and hope this helps you. Wishing all a Happy C-300'ly New Year Rich Barber 1955 C-300 (had it out and about yesterday--to the tranny shop to evaluate parts needs to stop minor leaks on the Powerflite. May need source of rear seal and shift lever seal. Any good sources out there? I have the pan gasket and replacement neutral switch. Noted an unused small bracket bolted to the bottom on the driver's side. Perhaps to hold an illegal backup light switch?) -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of mwl1967@xxxxxxx Sent: Friday, December 28, 2007 11:30 AM To: chrysler300@xxxxxxxxxxxxxxx Subject: [Chrysler300] How To Test? Fuel Sending Unit Can someone tell me what's the best way to test a sending unit without actually installing it in the car? Also, can/should the electrical connections inside be cleaned or resoldered? Thanks, Mike Laiserin K coupe painted and starting to look like a car again **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/