99 SX 600. Fuel gauge isn't working. I have replaced the in-tank sending unit because the old one had no continuity at all. New one has chancing resistance as you raise and lower the float rod. When the sled is off, the gauge is on E. Once you start the sled, the gauge shoots up to F and stay there regardless of fuel level in the tank. What else should I check? Does anyone have a wiring diagram by any chance? I think it may be in the wiring up by the gauge because it looks like someone did some "backyard mechanic" wiring.
The fuel meter should be powered by a Brown wire from the main switch. A Green/Black wire should go from the meter to the sending unit. The sending unit needs to be grounded. About as simple as it gets. Test resistance to ground with first the Green/Black disconnected, and then with the Brown disconnected (reconnect the Green/Black of course).
btw: You can see the wiring diagrams in the back of the Owner's manuals which can be viewed online at www.yamaha-motor.com if you no longer have the printed version.
btw: You can see the wiring diagrams in the back of the Owner's manuals which can be viewed online at www.yamaha-motor.com if you no longer have the printed version.
Thanks. So brown to the meter, green/black down to the sender unit and then sender unit to ground. As I understand, it regulates fuel level shown on the gauge by altering continuity to ground by the sender unit?
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You got it. The change in resistance alters the current flow (just a trickle) and the meter reacts to it.
I'll check it out this afternoon and report back. Thanks for the help.
Brown Wire to gauge = Has Power.
Green/Black out of gauge has continuity with Green/Black at the sender unit connector.
Ground at sender unit connector to engine block as a ground has continuity
Sender unit has resistance and continuity across the terminals.
When sled is off = Fuel gauge says E.
When sled is running = Fuel gauge always says F.
When sled is running and sender unit connector is unplugged, fuel gauge still says F.
Bad gauge?
Green/Black out of gauge has continuity with Green/Black at the sender unit connector.
Ground at sender unit connector to engine block as a ground has continuity
Sender unit has resistance and continuity across the terminals.
When sled is off = Fuel gauge says E.
When sled is running = Fuel gauge always says F.
When sled is running and sender unit connector is unplugged, fuel gauge still says F.
Bad gauge?
96YamVmaxXT
New member
After looking at the diagram and from what you have found it appears the gauge is faulty. But just as a last check you should remove the sending unit, have it plugged in, and check resistance from the green/black wire at the gauge to ground. Move the arm on the sending unit up and down and make sure its changing. This here would eliminate any other possible issues with the signal wire going to the gauge and checking operation of the sending unit itself at the same time. You should also double check the wiring around the gauge cluster and make sure everything is where it should be and nothing is chaffed or corroded. Hope this helps and keep us updated!
I'm still dealing with this issue... replaced the sending unit again with a known good one, replaced the gauge with a known good one as well. Resistance at the plug is changing as it should at the sending unit as well as the gauge plug. but the damn gauge still shoots up to full and stays there while its running regardless of fuel level. I'm really at a loss here?
Is there a spec that the resistance should be in ohms when the sender is down and when it is up?
raptorman2fast
New member
I have the same problem on my 600 SX. My solution was simple math. I average 12.2 mpg x 11.9 gal tank = 145 miles per tank +/- 5 miles. That and I fill up at every fuel pit I see. Now the broken fuel gauge doesnt even bother me.
webfoot
New member
I have the same problem so would love to read how you get this fixed.
first thought is sounds like the ground is bad.
whats the power(volts) in the power wire at idle?
whats the power(volts) in the power wire at idle?
braindead1684
Member
My dad's 94 vmax was doing something very similar it was a bad stator.