fuel indication?

[dale1]

greetings.

2002, 265 express with f-225s.

can you help me understand the fuel level indicaitons. I can not get the foward tank to read. I installed a new sending unit. "no help"

when i flip the switch foward, the guage reads empty. when I flip it backwards, it reads the appropiate amount in that tank.

any help appreciated. what is the basics of the wiring. could it be a bad switch or guage?

thanks,
dale

 

[Pez Vela]

Most likely a bad ground somewhere, but to test the fore/aft fuel tank switch, I'd reverse the pink wires at the switch, so that the aft tank is connected to forward switch connection point. If the aft tank still reads correctly when the switch is flipped to the forward position, that would indicate that the switch is good.

 

[dale1]

Most likely a bad ground somewhere, but to test the fore/aft fuel tank switch, I'd reverse the pink wires at the switch, so that the aft tank is connected to forward switch connection point. If the aft tank still reads correctly when the switch is flipped to the forward position, that would indicate that the switch is good.

Pez. thanks. so is the pink wire hot? the wiring on the sender is pink and black. the wiring on the boat is pink and green? can i perform a voltage test? also. there appears to be a ground point next to the sender. it is a tab sticking up on the tank. Should the sender be grounded there also? Sorry. I just dont know enough to troubleshoot properly!

thanks, dale

 

[Pez Vela]

Boat wiring is equally mysterious to me, so I hesitate to comment much further, other than to say that the sender's black lead goes to your boat's ground, and the pink lead goes to the switch. You may also play around with the sender you removed, hooking it up to one, then the other, fore/aft switch connections. Then, hold the sender in your hand and swinging the float manually and see what happens.

 

[jbrinch88]

greetings.

2002, 265 express with f-225s.

can you help me understand the fuel level indicaitons. I can not get the foward tank to read. I installed a new sending unit. "no help"

when i flip the switch foward, the guage reads empty. when I flip it backwards, it reads the appropiate amount in that tank.

any help appreciated. what is the basics of the wiring. could it be a bad switch or guage?

thanks,
dale

A fuel sender is simply a resister, and power is not sent directly to it. To test a fuel sender it really has to be removed. Hook up a meter to it and set it to ohms. Now watch the resistance increase and decrease (gradually) as you raise and lower the float. If the resistance increases and decreases gradually and doesn't jump around all over the place, the sender is still good.

The fuel gauge is what gets the power from ignition (on most occasions). The sender wire (from the dash gauge) goes from the gauge to your switch. Your switch then (depending on what tank is wired to each side of the switch) sends the appropriate resistance from that sending unit to the gauge, giving you your fuel tank reading.

In most situations I've been in, its usually the sending unit, a bad ground, or the switch. Gauges don't go bad to often from my experience. You already ruled out the sending unit by replacing it though.

 

[DennisG01]

If you remove the pink wire from the sender and touch it to ground (the sender plate, for example), the gauge should read full. With the wire simply removed, the gauge should read 0. This will at least help confirm if the problem is at the sender (sometimes new senders can be bad) or upstream (key needs to be "on").

If I remember correctly, as far as Ohm values, with the sender arm raised it should read about 30 Ohms and down should be 230 (make sure wires are disconnected for a resistance check).

 

[dale1]

thanks for all of the above. I'll try each test. is there a arch hazard while testing the pink wire to ground? thanks again, dale

 

[DennisG01]

The fuel to air ratio actually has to be pretty specific for an explosion to take place. Is there a risk? Sure. But common sense (and your nose) will tell you what to do. If you want to be extra cautious, make the connection and then have someone turn the key on.

 

[dale1]

Ok. can you please tell me if the toggle swtich "tank selector" is a three position or 2 position on most gradys with 2 tanks. My switch has been changed. It appears to be an off/on type. there is only 2 positions. Ive started trouble shooting. the sender is good. the ground is good. but i can not figure out the switch.

thanks,
dale

 

[jbrinch88]

The switch should be either a momentary on/off/on type switch or regular on/off/on if equipped with two tanks. Momentary the switch will Not stay engaged in the up or down position, a normal switch it will. Sort of like a Horn style switch but both ways. Most likely the wire in the center of the switch goes to your fuel gauge on the dash. The tank sender wires will be on each of the other ends of the switch. Usually opposing eachother i.e. (if your MAIN tank gets read by pushing the switch forward, the sender wire will be go on the bottom tab of the switch, if REAR tank is read by holding the switch back, the sender wire for that tank will be on the forward tab of the switch).

Hard to explain in words.

 

[DennisG01]

Dale - how many pink wires are on the back of the switch? 3? Don't focus on the number of "clicks" or "positions" for a moment - the switch could be an "on-on" switch. Remove the 3 pink wires (noting where each was) and test the switch: Using the same posts that the pink wires were hooked to, connect an ohm meter between the post that was connected to the gauge and one of the other posts. Flip the switch a few times and you should see the meter jump back and forth between infinity and awful darn close to 0 ohms. Repeat for the other post. If one particular switch position ONLY shows infinity, the switch is bad.

Another test to "test" the wiring (which can all be done on the back of the switch): jump the pink wire from the gauge to one of the other pinks. The gauge should read appropriately. Jump to the other pink and the gauge should again read appropriately - you are, in essence, manually selecting which tank you want to read. Also make a note of which pink wire comes from which tank.

 

[dale1]

OK, thanks. A new sender that i ordered a week ago came in. It is the correct length. So for giggles, i installed that one last night. "no help" It was still reading empty, and I know there is fuel in the tank. approx 1/4 tank.

So i downloaded a wiring diagram, and removed the dash panel to access the back of the switch. discovered three wires on the switch. Pink, Pink/white, and Pink.

one pink is for the guage, and the other is for the main tank sender, and pink/white is for the rear sender. the wires were in the wrong location. But the fuel guage still read 1 dash in the rear positon?

I wired it according to the diagram. Now the rear tank reads empty "or the bottom dash is flashing" which is correct.

But the foward tank indication is reading low. ONly one dash, when it has 1/4 tank of fuel. is that correct?

My confiendence level is low. we fish offshore, and i need to have accurate fuel readings. I've only owned the boat for 3 months, and have only put fuel in it twice. thanks, dale

 

[DennisG01]

Not sure about the dashes - I haven't had this particular boat (Yamaha) long enough. But... Where is the sender physically located in the tank and is the boat sitting bow high or low? That can certainly affect the reading. Maybe you should physically check the fuel level - get the tank perfectly level and then do a dip test through the sender hole.

Did you verify that the gauge will read correctly at full and empty (see test above)?

Do the engine manuals talk about the gauges and what the dashes mean?

 

[dale1]

Dennis,
the digital gauges have dash marks to show full to empty.
your right. I need to remove both senders, check the fuel levels with the boat level.

them i'm going to ohm the wiring from each sender, and varify the wiries are correctly installed on the switch. then, i'll ohm the contacts on the switch again. varify resistance on the senders. If all of that checks out, it must be a faulty guage.

thanks
dale

 

[DennisG01]

Sorry, I meant to say that I don't know what each dash means - in regards to how much fuel is in there or how accurate they are.

Here's another way that might make things a little easier/quicker: Take the wire coming from the gauge and short it to a ground. You should see the gauge read full. When you remove it from the ground, it should go to completely empty. That will tell you if the gauge is good. If that does not work - pull or access the back of the gauge and use a known-good wire to do the same thing (this eliminates the existing wire as a variable).

Another easy thing: After confirming what is actually in the tanks, just use a screwdriver (on the back of the switch) to short two of the terminals together -- the one going to the gauge and one of the tank terminals. Then do the other tank terminal. If you get the same reading as when actually using the switch, the switch is good.

As you can see, there's a number of ways to accomplish the same task. No one way is really better than the other. The most important thing is to do things logically and systematically. You also might want to jot down the tests you do and the outcome - just so you don't have to try and remember everything.

 

[dale1]

Special thanks to everyone especailly Dennis

with good trouble shooting technics "dennis" I figured it out. the two pink wires were switched. I not sure how long it been like that because i believe there was some feed back through the switch?? anyways it works correctly now. check out the youtube video

https://www.youtube.com/watch?v=Z0K9rAyokn8

 

[DennisG01]

The video isn't working, at least on my end, but that's great! It's especially great when it's a freebie! Now you have a spare sender and when/if it comes time to replace one of the them, it should only take you about 5 minutes.