Author Topic: Fuel pump (Read 2059 times)

Mikecocos · « **on:** February 14, 2018, 09:29:04 PM »

My low fuel sensor isn’t working properly. attached are pics of the fuel pump. Need some help to find the sensor on the pump. I am then going to test the resistance on the sensor.

rodekyll · « **Reply #1 on:** February 14, 2018, 10:06:37 PM »

Blue and white wires, iirc. You can verify that by tracing the red and black back to the pump. Whichever ones don't go to the pump are the ones you want.

Mikecocos · « **Reply #2 on:** February 15, 2018, 10:10:11 AM »

OK, thanks for this.

How does the sensor actually work? A previous thread mentioned that the sensor either uses a float or a thermostat to measure fuel. Does anyone know which system it actually is (the bike is a 2014 V7 Stone)? I plan to measure the level of resistance when the switch is "off" or "on" using a multimeter. Any tips on how to set the switch to off/ on? Or, any other tips on how to determine whether the sensor is working or defective?

Thanks in advance, fellow Guzzistas!

Cheers,

Mike

Wayne Orwig · « **Reply #3 on:** February 15, 2018, 11:09:30 AM »

In your picture it is the metal can on the side of the black pump. The corrugated hose runs past it. It has one wire, and there is second ground wire attached to one of the mounting screws if I remember right.

It is a thermistor. It is about 1.2k ohms at room temperature. As long as it stays wet with fuel, it stays around 1.2k (not an exact number). If it measures in the 1 to 1.4k ohm range it is good.

If it is uncovered, the small current through the bulb heats it up. That lowers the resistance, so more current flows. Thus more heat, and more current. Until the bulb glows or fuel cools it off again.

If it is not physically damaged/broken, the problem is likely outside the tank.

Wildguzzi.com · « **Reply #3 on:** February 15, 2018, 11:09:30 AM »

Kiwi_Roy · « **Reply #4 on:** February 15, 2018, 02:52:07 PM »

As Wayne says, I have only ever seen the sensor standing vertical before wire at the bottom fine slots at the top.
The fuel should run out the bottom end as the level drops so it can start heating up, yours appears to be horizontal, perhaps it's trapping fuel in there keeping it cool.
A word of caution if you are testing it, put it in series with a lamp that limits the current to ~100 mA, with 12 Volts on it will quickly get red hot and burn out.
If it does burn out the fine slots cool the gas down so your tank doesn't go BOOM

I believe the sensor is a Panasonic, I got a couple from a Chinese source a while back, very hard to find in NA., Triumph use the same sensor in their early Tiger, I'm sure it's used in hundreds of autos.
It won't work with an LED, must have a load. probably supplied by the dash.

https://www.datasheets.com/datasheet/ertlg12n7-panasonic-14690523.html

Mikecocos · « **Reply #5 on:** February 15, 2018, 04:17:11 PM »

Is there a way of testing the switch without immersing it in gasoline?

Kiwi_Roy · « **Reply #6 on:** February 15, 2018, 07:05:27 PM »

If you just turn it on it should indicate full for a few seconds then it will heat up and indicate low

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Kiwi_Roy · « **Reply #7 on:** February 15, 2018, 07:07:58 PM »

You could also dip it in water but it will take longer to recover from that

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Wayne Orwig · « **Reply #8 on:** February 15, 2018, 08:46:51 PM »

If it reads anything close to 1000 ohms it is good. It is a 'piece of rock'. If it works, it works.

On that design, the odds are it is outside the tank UNLESS the mounting tab is broken. I did see that happen once. Some really early designs had an external connector that could get swapped and damage it by applying 12 volts directly to it. Yours does not have those issues.

Measure it with an ohmmeter at room temp. Report back with the value. If you want, warm it up a bit with a hair drier and measue it. If it changes, it is absolutely working.

Mikecocos · « **Reply #9 on:** February 18, 2018, 07:59:49 PM »

I just measured about 1400 ohms. It was quite cold in the room I took the measurement in - so i think this aligns with the "normal range" provided in this thread. If it is not the sensor what else could it be?

rodekyll · « **Reply #10 on:** February 18, 2018, 08:26:32 PM »

Quote from: Mikecocos on February 18, 2018, 07:59:49 PM

I just measured about 1400 ohms. It was quite cold in the room I took the measurement in - so i think this aligns with the "normal range" provided in this thread. If it is not the sensor what else could it be?

Did you change the temperature of the sensor to see if the ohms changed?

It would help to know how the system is malfunctioning. All you asked earlier was how to check the sensor. Troubleshooting the problem is a different thing. So . . . tell us . . . why did you want to check the sensor? Is the light coming on too early? Too late? Ever? Is it on all the time? does it burst into flames?

We can probably help.

Wayne Orwig · « **Reply #11 on:** February 18, 2018, 08:32:22 PM »

Quote from: Mikecocos on February 18, 2018, 07:59:49 PM

I just measured about 1400 ohms. It was quite cold in the room I took the measurement in - so i think this aligns with the "normal range" provided in this thread. If it is not the sensor what else could it be?

Likely perfect.
And it is pretty close to a 'rock'. If it shows normal resistance, then the 'rock' is in there and will work.

Maybe simply a bad bulb, or bad connection.

Mikecocos · « **Reply #12 on:** February 18, 2018, 08:34:47 PM »

The low fuel light comes on very late. Sometimes not at all.

For context, I had a problem with rust in the tank. I have now fixed that issue.

Not sure to what extent the issues are related.

Kiwi_Roy · « **Reply #13 on:** February 18, 2018, 08:41:36 PM »

I mentioned the sensor should be vertical orientation to work properly so the fuel can drain out.

I asked because in the first picture you posted it seemed to be Horizontal

Mikecocos · « **Reply #14 on:** February 18, 2018, 08:44:57 PM »

The sensor is welded on to the pump frame. It cannot be moved.

rodekyll · « **Reply #15 on:** February 18, 2018, 08:54:20 PM »

Quote from: Mikecocos on February 18, 2018, 08:34:47 PM

The low fuel light comes on very late. Sometimes not at all.

For context, I had a problem with rust in the tank. I have now fixed that issue.

Not sure to what extent the issues are related.

Rust in the tank could mean rust inside the sensor cavity keeping the sensor wetter longer. That's the only cause/effect I can guess. Be sure there's no crud of any kind in there.

And maybe replace the indicator bulb and scrub up/Vaseline the contacts, both hot and ground. High resistance in the circuit could cause this too. An LED bulb might be more sensitive to the sensor, too.

Wayne -- just out of curiosity -- is the sensor a go/nogo thing or does it operate over a range like the toilet float-type in a car?

Mikecocos · « **Reply #16 on:** February 18, 2018, 08:58:26 PM »

Thanks. Tips regarding how to clean the sensor?

But seriously thanks. The depth of knowledge on this forum is impressive.

To respond to previous comment about the sensor orientation - see attached pic regarding how sensor is attached to the frame. Its orientation cannot be changed.

Mikecocos · « **Reply #17 on:** February 18, 2018, 09:02:35 PM »

rodekyll · « **Reply #18 on:** February 18, 2018, 09:43:47 PM »

With respect to Kiwi Roy's expertise in these matters, does that position make it vertical when the pump plate is installed?

Like Roy says, there's an intake and an outgo for gas flow through the sensor. Use that path to flush it, maybe in both directions. I'd think brakecleen or similar pressurized, light solvents would do it. Hold a white cloth or paper towel around the sensor to see if anything is coming out. It's really a longshot.

I was asking about the go/nogo thing to find out if the light is supposed to start dimly and brighten up or just pop on at full brightness. If yours is slow drying out and it is supposed to start dimly, it might be lighting up without getting bright enough for you to notice. High resistance at the bulb end of the circuit could do the same thing, as could corroded connectors anywhere along the circuit.

Does this pump arrangement have a single electrical connection, or is there a separate one for the pump and sender? Is it possible to misconnect the plugs?

Kiwi_Roy · « **Reply #19 on:** February 18, 2018, 10:09:34 PM »

David,
I think on the bikes with an electronic dash the LED light will switch hard on at least it does on my Griso. I suspect its an electronic switch in the dash or ECU that detects the threshold and turns on the LED
It probably has some deadband unlike the incandescent lamp and sensor in the earlier Californias.
Roy

rodekyll · « **Reply #20 on:** February 18, 2018, 10:12:07 PM »

Thanks for that, Roy. That means I've offered all I can.

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Author Topic: Fuel pump (Read 2059 times)

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