SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: TCRUSH on March 25, 2009, 01:12:49 PM
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I have dual tanks. I have a toggle switch on the dash to switch tanks. When the tanks are full the gauge reads 1/2 full on both. Usually that means a bad ground. I looked at the sending unit on one tank and they ran the ground to one of the 4 bolts that hold down the gas fill lid. I dont see that being a good ground. Do I run it to the block or to the terminal block? Where does your grounds run to from the sending unit? Thanks for your help.
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Everyone i have seen has been grounded to the tank where the sender is.
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I'm having gauge issues too, grab an ohm meter and check the sending unit. It should read like 240 ohms empty and 33 full, for most gauges.
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The ground is connected at the sending unit but the other end usually goes to a good ground. I'm not sure with a boat since its all fiberglass. Would it work to run a small ground from the engine block to the terminal block, then run both grounds from the sending units to the other screw on the terminal block?
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Ok i will go out and trace my wires ;D
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Yeh you can ground to the block, or the battery, or the terminal block(which is probably grounded to the block). I thought without a ground the gauge would just peg.(not read halfway) I'm guessin it's either the sender or the gauge, prolly the sender. Let us know what you find.
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the wire in the center of the sender is for the gauge. The ground is wired from the ground terminal or block to one of the 5 sender attaching screws. The wire that goes from the sender attaching screws to the fill neck is the ground for the filler neck. Check the ground connection for good contact.
p-jet
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It sounds like I should leave the wire going to the filler neck but also run a ground from the sending unit to a good common ground like the terminal block or engine block.The ground wire coming off the sending unit to the filler neck probably wont ground the sending unit.The filler neck is touching fiberglass. I think I will try and run a wire from the sending unit to a solid ground and see what happens. I will keep you guys posted. Thanks for the help.
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I'm not sure if its right or necessary but here's how it was done on my Daytona. I just put the tanks back in so I snapped a couple shots for you.
There are grounds on the filler caps, the senders and the tanks themselves. :sly: Not sure why it has them on the tank bodies but it does. :-\
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too find a ground do the opposite with a test light...a test light wont work unless it has power and a good ground...hook the clip to a power source and start touching possible grounds...does this make any sense?
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I understand, but I thougt that was common knowledge
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must be if i know it
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must be if i know it
:D
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I'm not sure if its right or necessary but here's how it was done on my Daytona. I just put the tanks back in so I snapped a couple shots for you.
There are grounds on the filler caps, the senders and the tanks themselves. :sly: Not sure why it has them on the tank bodies but it does. :-\
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Do you suppose that filler neck ground is to eliminate the chance of a spark while refueling???? I dunno, just asking.
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Do you suppose that filler neck ground is to eliminate the chance of a spark while refueling???? I dunno, just asking.
I was thinking the same thing. It makes sense to me to have the tank/sender and the filler neck grounded, Wouldnt want to creat sparks when shoving the gas nozzle in...
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My boat always tells me when im out of gas. :sly:
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Thanks for the pictures. Thats how mine looks too. Where does your ground run to that comes off the tanks? I'm also guessing that the ground that runs to the filler neck is for static. Mine tells me when its empty too. I found that out this weekend. It just shut down, Switched tanks and was off again. I think I need to make a good ground from the block or battery and run everything to that. Thats a good idea with the test light. Clamp the clip to a power source and touch the sending unit grounds and see if the light comes on. I will try that.
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I have a problem suspecting two bad grounds which is what you're showing. How did they wire up the switch to indicate the different tanks on the gauge? If they have the senders paralleled you're cutting your resistance in half. They must stay seperate.
Just a thought.
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I have a problem suspecting two bad grounds which is what you're showing. How did they wire up the switch to indicate the different tanks on the gauge? If they have the senders paralleled you're cutting your resistance in half. They must stay seperate.
Just a thought.
Yeah I'm going to X2 this idea as a possible reason both gages only read to 1/2 when they are full. Not likely that both senders are bad. Or, the gage is the problem kid and it has a poor ground or something. So I'm voting for a check of the quality of connections and type of switch you have and the wiring between it and the gage.
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Until he checks the ohm's on his sending unit, full and empty, I guess we will never know. :sly: