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Tips

Fuel gauge calibration procedure

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It is a very delicate instrument inside and the fine wires will break with much movement. It is adjustable but my experience is leave it alone. There are two small nuts that can move in a slot on the back of the gauge. This is the adjustment. I don't remember which way to move them.
 
Another option is:

Send it in to Nisonger and have it calibrated.
 
SteveHall64Healey said:
I’d like to calibrate the fuel gauge on my BJ8. A full tank shows over full, and the tank is empty at 1/4 tank. Does anyone have, or know of, a good procedure?

thanks
Steve
Click to expand...

If the gauge shows 1/4 tank when empty, this can be because the sender float arm is pointed to the rear. If that's the case, the arm hangs up on the side of the well and will show 1/4 tank when completely empty. If necessary rotate the sender so the arm points forward.
 
Thanks- I know about Nisonger, but am not keen to send it there. I believe that if I give it to any tech they would need resistance readings from the sender at full and empty positions.
 
Thanks - I replaced the sender about 5 years ago and I can’t remember which way I installed it. I vaguely recall pointing the float to the rear. Thanks for the tip!

I am compiling my winter projects at the moment and will check which way it points when the car comes off the road.

I’ve generally wintered the car with a full tank of gas with fuel stabilizer. Any recommendations re this?
 
SteveHall64Healey said:
I’d like to calibrate the fuel gauge on my BJ8. A full tank shows over full, and the tank is empty at 1/4 tank. Does anyone have, or know of, a good procedure?

thanks
Steve
Click to expand...

I just did this for my BJ8 after I discovered that the float had been rubbing/binding on a baffle inside the Moss replacement tank, making the gauge erratic. Please contact me at sbyers@ec.rr.com and I'll detail the procedure for calibrating the gauge. As others have noted, you have to be very careful not to loosen the adjusting nuts too much, or you can spin the post when you re-tighten them and break the coil wire. That will permanently disable the gauge until the wire is replaced by a professional.
Basically, you remove the green/black "T" wire from the gauge and measure the resistance between the wire and ground with the tank full and empty. Using the resistance values, you build a test set with resistors. When the gauge is connected to a 12 Volt source, the test set resistances for FULL, HALF, and EMPTY are used to adjust the position of the gauge needle for the correct reading. It's a bit of trial and error because the gauge FULL and EMPTY coils pull against each other to position the needle. The adjusting nuts are loosened just enough so that moving the posts in their slots affect the needle position. Better for them to be difficult to move than too easy.
 

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For any vehicle that I'll store over the winter, I'll try to run the tank low and use no-ethanol premium for the last couple of fills, irrespective of the stuff that it burns normally. Add the fuel stabilizer and make sure that it's mixed well enough and the vehicle is run long enough to get the stabilized fuel through the system. I do a bit of digging each fall to see which of the local gas stations offer non-ethanol premium and go there. Mr. Turney has a great point regards shutting down the fuel pump - I'd never thought of that - could you pop a fuse? I think that the engine might continue to run with the battery swicth turned off, but I don't know enough about the function of the battery in damping out electrical surprises.
We've had a bit more than 10 inches of snow in the last week or so, but it's supposed to get seasonal next week (low 50s; above seasonal!) and I haven't 'winterized' the law mower yet. Figure I'll empty the gas tank, run the engine 'til it stops, change the oil, and spray the heck out of the interior of the gas tank with WD-40. Later, Doug
 
In a stock installation, the fuel pump isn't fused. It's one of the white wires on the feed side (A3) of the 35A fuse. The other white wires go to the overdrive.

I have a dual-sided pump with switches for each side.
 
I finally got around to this job this morning, and the electrical connection is facing the rear of the car. As well, upon removal of the cover plate housing the rheostat, the gauge shows full with the moving contact pointing forward. The sender must have been installed (by me :-() ) facing the rear. A new set of gaskets just arrived so I will reverse it and test it when driving season arrives here.
thanks
Steve
 
I have reversed the orientation so that the float points forward. I the tried Viton gasket set from Moss which gave me more confidence in the seal as opposed to the cork gaskets they replaced.

Once installed, I pushed the rheostat forward and backward and got an Empty indication on the gauge with the float bottoming out in the tank and Full indication with the float at maximum height. Should be good for driving season starting in April...

thanks for the input everyone,
Steve
 
Unless it has been modified there is a wire from the cut off switch in the trunk that will short out the coil. At least it is on the BJ8 that I have. I don't know about earlier cars.
 
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