Round Twelve - Cruise Control & Fuel Gauge Gremlin
June 13, 2004, 65,107 miles:
Well, just putzin around this weekend. My gas gauge exhibited the typical weird behavior... It would take a long time to get down to half full, then it would move a bit quicker to about 1/3 then it would plummet quickly, going through the last "1/4" tank very quickly. It's located under the rubber plug pictured below, which resides in the middle of the cargo area that is next to the tire well:
Ugh.... looking pretty bad in there. I used a paint brush and a shop vac to clean the area up... I didn't want any of that crud in the tank. Note: Don't mess with this unless you're sure the fuel level is far below the bung!
I disconnected the hose and the electrical plug, then unscrewed the ring holding it in. The gasket on it was still fine, which I found encouraging.
The plastic piece on the bottom seems to be intended to prevent any crud from getting sucked up, but looks as though it will leave a good 1/2" or so of fuel in the tank minimum. The nut is 5.5mm so be sure you have the right wrench.
The plastic piece on the bottom was keyed so that it could only be mounted to the sender in one orientation. No big deal, just worth noting for reassembly. One more 5.5mm nut and the black plastic endpiece and the aluminum tube come off. Careful, the innards are delicate!
Here are the electrical connections that come through the top flange. The float moves up and down along the two wires, varying resistance. Very unusual in my experience; I'm used to floats on levers that run a wiper past a section of wound wiring.
At the very bottom of the unit are these two pointy contacts that are shorted by a metal disc on the float when it reaches the bottom of it's travel; this engages the "low fuel" warning light. I cleaned everything up and put it back together. I filled the tank and checked for leaks. I'll know as I go through this tank what sort of results I get. If my fuel gauge still misbehaves I'll just replace the sender.