trouble shooting fuel gauge

[fishing1]

I have a 96 Javelin F/S and my fuel gauge has been reading below empty for quite some time. I heard you can run another ground from the back of the gauge to see if you get movement, it did not. However, when I put a ground to the sender terminal it showed close to the right amount of fuel. I need some guidence.



thanks, Darel

 

[gss036]

Re: trouble shooting fuel gauge

Sounds like you sovled your problem. Connect the ground and it should work.

 

[Todd Peterson]

Re: trouble shooting fuel gauge

Yes,

A good ground can solve gage problems. Give it a try and hit the water.

 

[Silvertip]

Re: trouble shooting fuel gauge

Grounding the sender terminal does not make this a functional system. It merely proved the gauge itself is functional. Go here to look at an entire post about fuel gauge system wiring.

http://forums.iboats.com/showthread.php?t=275333

 

[fishing1]

Re: trouble shooting fuel gauge

thanks guys, I will give it a try and see what happens. Silvertip I am going to check out that site. One more thing, if I do need a new fuel gauge how do I know which one's will work? Will a genaric gauge from a auto parts store work and if not where should I look?



Thanks again, Darel

 

[fishing1]

Re: trouble shooting fuel gauge

Silvertip, I looked at your diagram and you show only two wires coming from the sender, I have three. Allright let me try to explain. When I put a ground on the sender terminal at the back of the gauge it jumps to full.(was at empty) When I remove the ground it reads 1/2, which is correct. When I turn the key off the gauge shows below empty and then I turn the key back to the on postion the needle only comes up to a little more than empty.


Thanks for all your help, Darel

 

[fishing1]

Re: trouble shooting fuel gauge

ok, on my sender there is a pink wire coming from the center like the diagram shows. On the side of the sender there is a green wire running to the fuel neck and a yellow wire running into the same harness as the pink wire. I put a ground from the battery to the far side of the sender like the diagram shows and bad things happen. So confused.


thanks again, Darel

 

[Silvertip]

Re: trouble shooting fuel gauge

What "bad things happened". The wire coming from the fuel filler neck is a static ground. You need to find out where that yellow wire goes. The sender simply cannot work without a ground so it must be connected either to the negative terminal of the battery or run all the way forward and connected to the ground buss on the fuse/breaker panel (which is a waste of wire since that point is connected back to the battery anyway). You have a wiring issue or you have a three wire sender. Three wire senders have two "insulated terminals" like the one that the pink wire connects to. Those senders require a +12 volt connection when the key is on. The third wire is sender ground.

 

[fishing1]

Re: trouble shooting fuel gauge

Silvertip, the bad thing that happened was that it sparked and tried to melt the jumper. I did not trace the yellow wire however, there is a yellow wire of the same size connected to the pos. side of the battery. So I took it off the pos and touched it to the neg and the gauge went to fuel and the down to 1/2 when i removed it from ground. The gauge has worked for years the way it is, unless there is a chance i got some wires crossed.


thanks alot for your help, Darel

 

[Silvertip]

Re: trouble shooting fuel gauge

OK -- lets concentrate on the green and yellow wires. You said both of those wires connect to the same point on the sender -- is that correct? The terminal those two wires connect to is riveted or screwed to the shell of the sender -- is that correct? You said the other end of the yellow wire is connected to the POS terminal of the battery -- is that correct?

 

[fishing1]

Re: trouble shooting fuel gauge

silvertip,

yes,
yes,
and the yellow wire disappears into the great unknown of a wire harness, but I would assume that the yellow wire on the pos. side of the battery is the same as the yellow wire on the sender because if I remove the wire from the battery, I can put a ground to that terminal on the sender and it does not spark like it did with the yellow wire connected.

thanks, Darel

 

[Silvertip]

Re: trouble shooting fuel gauge

That yellow wire at the POS terminal of the battery cannot be the same wire that's connected to the ground lug on the sender. If it was, there would be smoke and burning insulation. You cannot connect a wire to the positive terminal of the battery and ground as that forms a direct short. I really think the wire you are missing is a ground between the shell of the sender and the negative terminal of the battery. The system cannot work without it unless this is a metal tank and the tank itself is grounded. Where that yellow wire goes probably the key this mystery. Do any of those wires look like they've been messed with -- in other words does everything look original.

 

[fishing1]

Re: trouble shooting fuel gauge

Silvertip, remember the bad things that happen? lol. When I run a ground wire from the neg on the battery to that post it does result in a short, unless i take the yellow wire off of the POS on the battery. With that said, when I take the yellow wire off the POS and put it on the NEG the gauge will go from empty to full, when i remove the yellow wire it goes to 1/2 which is correct. once the key is turned off and back on again it reads empty like it resets.

 

[Silvertip]

Re: trouble shooting fuel gauge

Exactly. Follow me here. The yellow wire that you have connected to the positive terminal on the battery is indeed connected to the shell of the sender which is WRONG. the only reason it doesn't create a problem is the sender is NOT grounded -- that's as far as current can flow. The minute you do that by adding the jumper, you create the short. Current flows from the positive terminal of the battery, through the yellow wire to the sender shell and then through your ground jumper back to the NEG terminal on the battery. That's a short circuit. Get rid of that yellow wire bacause it should be black. Then connect the new black wire from the shell of the sender to the NEG battery terminal. Then wire the dash gauge as shown in my diagram.

 

[fishing1]

Re: trouble shooting fuel gauge

allright, now that we agree that we argee. when i connect the ground to the sender, the gauge reads full (only 1/2 tank). when i remove the ground the gauge comes down to 1/2. then when i turn the key off and back on again it shows empty untill i go through that little process again

 

[Silvertip]

Re: trouble shooting fuel gauge

That goes back to one of my very first comments. You are not making the gauge read correctly. You are merely testing the gauge. When you remove the wire and turn the key off everything is now put back wrong. You have a wiring issue. I can't see your boat so I've done as much as I can. If the wiring is not like the diagram shows, and the sender is not functioning properly, the gauge will not work correctly.

 

[fishing1]

Re: trouble shooting fuel gauge

thanks anyway