Fuel Qty indicator

[Cortez]

IS there PM outside of this thread? Where does it say it flashes when full? The original post is a question.

I know English isn't my first language but I think the OP made the point that
the fuel indicator flashes all the time regardless of fuel level pretty clear in
his first post. No PMs.

 

[fb40dash5]

Let me help!
IMO there is no cooling to the pump and no impact from running beyond 11lt/3.0gal or even 15lt/4.0gal. With the pump being inverted, the motor is out of the fuel for cooling purposes past a 1/2 tank anyway, so its moot point. Unless your counting on "splish splash" for cooling?

HOWEVER, the fuel does lubricate the impeller and without it, it will wear so running completely out of fuel and sucking air can lead to pump failure. Not to mention pushing the bike!

Fuel is always being pumped, and a lot of it returned to the tank. Between pumping it and heat soak from the engine, the fuel gets warmer. The pump is cooled not just by sitting in fuel, but by the fuel flowing through it. When the tank is full, it takes a lot more to heat up that large quantity compared to having a gallon or so going around, so it's cooling the pump more.

Just think how long any FI pump runs, and how hard it's working... pushing fuel basically any time the engine runs. I've seen a few that ran but didn't pump or had low pressure, but 99% of failures I see are toasted motors. Most of those that are premature are either out of fuel when I get them (many times have I dumped a can in a tank to check fuel pressure, and still had to replace the pump) or it's someone who habitually just puts $20 in their tank when the light comes on.

 

[Cortez]

Just think how long any FI pump runs, and how hard it's working... pushing fuel basically any time the engine runs. I've seen a few that ran but didn't pump or had low pressure, but 99% of failures I see are toasted motors. Most of those that are premature are either out of fuel when I get them (many times have I dumped a can in a tank to check fuel pressure, and still had to replace the pump) or it's someone who habitually just puts $20 in their tank when the light comes on.

I think with the current prices of gas in USA $20 is more then a complete fuel tank for the FZ6.
I can get it up to about 3/4 for $20 here.

 

[fb40dash5]

I think with the current prices of gas in USA $20 is more then a complete fuel tank for the FZ6.
I can get it up to about 3/4 for $20 here.

It also doesn't have a low fuel light.

I was referring to cages, being that's what I work on, and what burns out fuel pumps 20:1 over bikes. Seriously, when I do a fuel pump, one of two things is almost always the case: the tank is dead empty, or it's 100% full because the owner just about ran out and filled it up just before the pump died. Running the tank low chronically is a surefire recipe to prematurely kill the pump.

 

[Cortez]

It also doesn't have a low fuel light.

The blinking thing is good enough for me.

I was referring to cages, being that's what I work on, and what burns out fuel pumps 20:1 over bikes. Seriously, when I do a fuel pump, one of two things is almost always the case: the tank is dead empty, or it's 100% full because the owner just about ran out and filled it up just before the pump died. Running the tank low chronically is a surefire recipe to prematurely kill the pump.

Yeah, that makes sense..

 

[mnuttall87]

I always love reading these threads hoping that one day I will fix my broken fuel meter. Mine does the blink 8 times/pause for 3 seconds no matter how much fuel is in it -- I still need to dig around and see what is causing it.

If I'm not mistaken, the F-Trip will still come on, even with the blink 8 times/pause 3 seconds error though? I'm going to test that riding to work this week.

 

[Cortez]

I always love reading these threads hoping that one day I will fix my broken fuel meter. Mine does the blink 8 times/pause for 3 seconds no matter how much fuel is in it -- I still need to dig around and see what is causing it.

If I'm not mistaken, the F-Trip will still come on, even with the blink 8 times/pause 3 seconds error though? I'm going to test that riding to work this week.

If the F-Trip comes on at the correct time (the real reserve), I'd just ignore
the fuel indicator then and rely on that.

My last bike didn't have anything but a reserve light, which is the same as
the flashing last bar (when everything is in proper working order) or the
F-trip that comes on at the same time.

 

[FinalImpact]

Fuel is always being pumped, and a lot of it returned to the tank. Between pumping it and heat soak from the engine, the fuel gets warmer. The pump is cooled not just by sitting in fuel, but by the fuel flowing through it. When the tank is full, it takes a lot more to heat up that large quantity compared to having a gallon or so going around, so it's cooling the pump more.

Just think how long any FI pump runs, and how hard it's working... pushing fuel basically any time the engine runs. I've seen a few that ran but didn't pump or had low pressure, but 99% of failures I see are toasted motors. Most of those that are premature are either out of fuel when I get them (many times have I dumped a can in a tank to check fuel pressure, and still had to replace the pump) or it's someone who habitually just puts $20 in their tank when the light comes on.

If the DC motor really needed cooling, its design would it laying at the bottom of the tank vs encased in plastic pointed skywards. In this case the pump is vertical so its only cooling is air and splash when the fuel level drops. The pump lives a long life because of its design. Although it has high start up current it doesn't make an abundance of heat which requires cooling so its a non-issue.

Also there is no return on this system. When it reaches pressure it dumps from the over pressure valve into the tank. I know the R6 uses a return line but not our FZ6. Notice ours has a single output while the R6 has an outlet and an inlet.

As I stated before, the bulk of the damage comes pumping debris and from cavitation (sucking air). That mesh filter doesn't stop all things. Thus when debris is pumped and forced through the pump it opens its internal clearances rendering it less effective at building pressure.

**
As far as troubleshooting this circuit. The sender wires should also have battery voltage present when the key is on. In addition to the Ohm test of the sender and the resistor test of the harness, this can help isolate what is at fault. More than likely its just a bad connection even though it "looks OK".

NOTE:
This fuel meter is equipped with a self-diagnosis system. If the electrical circuit is defective, the following cycle will be repeated until the malfunction is corrected: “E” (Empty), “F” (Full) and symbol “ ” will flash eight times, then go off for approximately 3 seconds. If this occurs, have a Yamaha dealer check the electrical circuit.

 

[fb40dash5]

If the DC motor really needed cooling, its design would it laying at the bottom of the tank vs encased in plastic pointed skywards. In this case the pump is vertical so its only cooling is air and splash when the fuel level drops. The pump lives a long life because of its design. Although it has high start up current it doesn't make an abundance of heat which requires cooling so its a non-issue.

Also there is no return on this system. When it reaches pressure it dumps from the over pressure valve into the tank. I know the R6 uses a return line but not our FZ6. Notice ours has a single output while the R6 has an outlet and an inlet.

As I stated before, the bulk of the damage comes pumping debris and from cavitation (sucking air). That mesh filter doesn't stop all things. Thus when debris is pumped and forced through the pump it opens its internal clearances rendering it less effective at building pressure.

You can think what you want. Sucking crap through will absolutely help kill a pump, as will sucking air, but pumping air or debris in and of themselves aren't going to damage the motor electrically. Overheating it will, and if it's not getting cooled by fuel, it's going to overheat. Choose not to believe me if you wish. I replace fuel pumps regularly, almost all due to motor failure, and the common thread is that the vehicle has almost always been run low on fuel recently, and usually pretty often. I regularly tell customers that if they want to just put 5 gallons in their tank at a time, that's fine, but make it the top 5 gallons you're putting in, not the last... keep it towards full, not empty.

PS: What do you think the return from the pressure regulator back into the tank is called? It might not leave the tank, but any action (being pumped) besides sitting there is going to make the fuel warmer. Less fuel in the tank = lower cycle time for x quantity of fuel before being run through the pump again, introducing more heat to it. By the time you sputter out of gas, that's been adding up for a while, then you make it worse by sucking air and losing almost all cooling.

 

[TownsendsFJR1300]

I know English isn't my first language but I think the OP made the point that
the fuel indicator flashes all the time regardless of fuel level pretty clear in
his first post. No PMs.

Ageed 100 % .

Randy posted shortly thereafter questioning that. Post #19: "Where does it say it flashes when full? The original post is a question " That's why I posted a response for the op (just to verify)

Of course, we're the only one's posting, the op isn't

Agreed, it is indeed a one fuel line system, it does not have a return fuel line. Cooling the fuel/fuel pump is also a moot point and off topic/issue.

The original post was re his gauge blinlkng constantly.

IMO, the most simple and likely reason, is either the float in the tank came loose, the connector(or wires) under the tank came loose, or the switch (clipped onto the fuel pump itself) went south..

Until the op chimes in and does some checking,(or posts something) it really doesn't matter..

 

[FinalImpact]

See comments below for cheap troubleshooting options.

If it were mine I would isolate the tank from the bike. You can do so with a cheap variable resistor and an ohm meter. Here is how.

To test the Bikes Harness and Meter:
You need a variable resistor or a "trim pot" capable of 20 to 140 Ω. A zero to 500 or 1K will do. First set it to 20 ohms using an ohm meter. Connect it to the bikes Green/W trace and Black wires and verify the meter reads full when the key is on.
Then adjust the pot to 135 Ω and verify it reads empty when the key is on. At this time it should also flash after a while.

With this $10 trim pot (there cheaper ones, thats just an example, see link), an ohm meter, and some alligator clips, you could test the bike! 3590P-2-201L Bourns Inc. | 3590P-2-201L-ND | DigiKey

To test the Tank sender:
Connect leads to tank as follows to Ohm the tanks sender.
• Positive tester probe Green/White (where the connector plugs in)
• Negative tester probe Black (where the connector plugs in)

Fuel sender resistance (full)
20–26 Ω at 20°C (68°F)
Fuel sender resistance (empty)
134–140 Ω at 20°C (68°F)

Now find a way to fill it and empty while keeping it level with your meter attached. I.e set it between two chairs so it CAN NOT FALL, and connect a meter. From Empty to full this test could be done in a safe manor. Or take the sender out.

I'm positive this is easier said than done, but if you have an Ohm meter, you can verify if the sender works by connecting the leads to the Green/W trace and Black connections at the sender.

Hope this clear things up! :thumbup: And obviously don't waste your time doing this if the Sender wires/leads to the tank are damaged. Repair them first!

Anyone needing to diagnose their fuel gauge, here's cheap option to simulate the tanks sending unit. Order these fixed resistors and simply bend them so they connect to the plug-in harness on the bike and turn the key on. Now see what the meter reports. It will cost you more in shipping than the individual 10 cent parts. This will simulate the sender without a need for an ohm meter.

Fuel sender resistance (full)
20–26 Ω at 20°C (68°F)
Fuel sender resistance (empty)
134–140 Ω at 20°C (68°F)

Insert one resistor at a time into:
• Green/White & Black (where the connector plugs in)

Buy one of each (link) all are $0.08
24 ohms - simulate a full tank
CF14JT24R0 Stackpole Electronics Inc | CF14JT24R0CT-ND | DigiKey

56 ohms - simulate a 1/2 tank << THIS IS GUESS, The tank IS NOT sysmetrical so this may be in error!!!
CF14JT56R0 Stackpole Electronics Inc | CF14JT56R0CT-ND | DigiKey

130 ohms - simulate a empty tank
CFR-25JB-52-130R Yageo | 130QBK-ND | DigiKey

7.5 ohms. They don't make a 134 or 140 ohms, buy a 7 ohms and connect them in series with the 130 ohms if you want it that close.
CFM14JT7R50 Stackpole Electronics Inc | S7.5QCT-ND | DigiKey

 

[Joseharris]

Been away from this forum for a while, just realize there has been some further feedback. For which I thank you all !!

Regards to how I determine tha amount of fuel in the tank with the faulty indicator, is in relation to milage (klmtrs) versus amount of liters I put back in when refueling.

The most I ride between fills is 150 km in the city and 220 km on the road.
The most I have refueled has been 11 ltrs.
Being a 19.4 ltr tank, half a tank would be 9.7 ltrs. So I have gone down to somwhere between half and a quarter tank.

Me and my mechanic will be taking the tank apart this weekend. Hope to have some news on monday !!

Again thanks for your feedback !!

 

[TownsendsFJR1300]

Any updates????