RWD - Update on fuel sender repair

Volvo RWD 900 Forum

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Update on fuel sender repair 900 1994

Fellow brickers,

I mentioned many moons ago regarding repairing my fuel sender. The fuel gauge seems to stuck mostly at 3/4 position with full tank.

Undoing the tank's plastic bung nut was easy. I used my IPD oil filter pliers at its largest opening. Taking the unit out was hard even after reading so many tips on this. Sweaty too in this tropical climate. The aim was to get the long sender tube (plus the attached in-tank pump) to clear off the fuel bowl at bottom of tank.

Once the unit is out I took the long sender tube out by unscrewing the top metal tab with spring and cutting off its two sending wires (to solder back when finished). The sender tube was made of two halves joined in the middle with plastic tabs. Dismantle the tube by slightly twisting its halves in opposite directions (about 1/8 of a turn) then pull them apart. Done this way to avoid pushing the tabs in and risk breaking some old plastic.

Then I could see WHY the gauge stuck because the float inside was stuck too along the sensing rods. There wasn't any fuel deposit or dirt to begin with. The PROBLEM was the resistance wires that were coiled lengthwise along the rods had become slightly UNDONE/LOOSE thus hindering the float's travel. So spraying with carb cleaner won't do.

To repair, twist the rods while tightening the coiled wires along the rod's length and there'll be some excess wires at the bottom of those rods. I had about 1 cm of excess wires at the bottom. Loop these excess wires while tucking them out of the float's travel (use toothpick or similar tool to loop). Put it all back together. The float should now travel freely inside the tube. Next, test for resistance. At topmost float position the resistance was 0-3 ohm and lowermost 130-145 ohms. Connect the sending unit back to the car to test (put unit far away from tank's opening to avoid any incident). Turn ignition to KPII (the in-tank pump should run momentarily) and tilt the unit to test both end float positions. The fuel gauge should slowly follow suit.

Of course installing the unit back into the tank took almost 1 hour. Just to get the tube (and in-tank pump) into the fuel bowl. Weirdly the "tie with string" method didn't work this time around. Someday I must learn how to cuss. Anyway my gauge now registers full with full tank.

May this helps,


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New 2 Update on fuel sender repair [900][1994]
posted by  Amarin  on Fri Apr 6 09:29 CST 2018 >

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