Fuel gauge problems

magicbandit

Cadet
Joined
Nov 18, 2002
Messages
27
Hi, I have a 1990 Formuls 223 ls<br />I am having a fuel gauge problem. With a full tank(80gallons) my gauge on the dash only goes up to just below half. The gauge system is a VDO brand.<br />Is the problem most likely the sending unit in the gas tank or the gauge on the dash itself. Any help and opinions would be appreciated. <br /><br />Thanks,<br />mike
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Fuel gauge problems

magicbandit <br />Most likely it's your sender and not the gauge. Remove the sending wire from the sending unit and ground it with the key on. It should go to full. If it does, replace the sending unit. You can get them for $20-$30 at most marine stores.
 

Franki

Lieutenant Junior Grade
Joined
Feb 16, 2002
Messages
1,059
Re: Fuel gauge problems

Fuel guages usually rely on a float hooked up to a variable resistor..<br /><br />I suspect in your case, the problem is either your float. (sender unit.)<br />or the wiring to the guage.. <br /><br />since the reading is determined by the resistance.. a bad connection somewhere can increase that resistance giving a false reading as a result.<br /><br />rgds<br /><br />Frank
 

crab bait

Captain
Joined
Feb 5, 2002
Messages
3,831
Re: Fuel gauge problems

is it ok/safe to ground out a wire,, with 80 gal of gas..??<br /><br />just had to ask..
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: Fuel gauge problems

Magicbandit<br />I would start by checking your mechanical gauge and seeing if it is also wrong. If it is then you have a problem with you sending unit in tank. Can be just a bent arm in tank. If mechanical is ok and dash guage is wrong then can be a loose or corroded conection on sendor wire or ground wires. Can also be bad guage, some have adjustments. Watch the guage while you move and tighten connections.
 

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: Fuel gauge problems

majic - Had the same problem with my Wellcraft this year. Suggest that you open the access plate to the tank. Mine had the tank manufacturer's label on the tank with the tank model number. I called them and bought the sender that was called for for my tank. This is important since the configuration of the tank must be considered so that the sender will send the correct reading to the guage on the dash. I think that I will get a more accurate reading than with an after market one.<br /><br />If the label is not on the tank, call Formula and ask.
 

walkingfish

Seaman Apprentice
Joined
Jun 3, 2001
Messages
48
Re: Fuel gauge problems

Hey Magicbandit,<br /><br />This will either help you out, or make you laugh!<br /><br />I had the same problem as you seemed no matter how full i filled her up it would read a max of half a tank, needle straight up 'n down.<br /><br />Grounded the gauge, and the needle went past the full mark, so i presumed it was the sender.<br /><br />Pulled out the sender, it looked ok but i pulled it to bits and cleaned it anyway, after cleaning i hooked it up outside of the tank and manualy moved the float arm on the sender - the gauge still only read half a tank at most.<br /><br />Pissed off by now i pulled the gauge out of the dash and pulled it apart, dont do that! couldnt see anything of note inside the gauge, so now really pissed off i started to put it all back together.<br /><br />Heres the kicker, as i put the gauge back in the dash i noticed the needle moved - without power.<br /><br />A bit of thinking later and i realised my problems with the gauge started about the same time i installed an extension speaker for my VHF, i mounted this speaker directly under the fuel gauge.<br /><br />It appears that the magnetic force of the speaker was to much for the gauge to overcome, hence the needle tried to stay dirctly straight up and down as much as possible.<br /><br />Moved the speaker, kicked myself in the pants, and now all is good :) <br /><br />Sorry, just a long winded way of saying, look simple before getting stuck in, may save you time<br /><br />boatin happy,<br /><br />W'fish
 
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