Fuel gauge failing

[MichaelH]

I've read a couple of existing posts about fuel gauges, so I think I need to replace the sensor inside the tank. But, let me give a few details and see what y'all think.

 

I have a 99 RSV that has under 1000 miles on it. Was sitting in some garage in pieces and put back together by the person I purchased it from. I replaced the main wiring harness b/c the person who took it apart in the first place did some stupid, nasty stuff to the wiring.

 

Well, once I got it electrically working, and had the carbs rebuilt, there is still this odd fuel level reading issue. I DO get the yellow light telling me my tank is low, but my fuel level never reads anything but a blinking single bar after fill-up. I've pulled apart the connector under the black tank cover and put it back together, giggled it around a bit, and no change.

 

Should I replace the whole piece inside the gas tank (4 screws, rotate it a bunch till it pulls out)?

 

Thanks!

- Michael

[V7Goose]

It would seem unlikely that your fuel sensor is bad. The fuel gauge on the RSV never blinks in normal use. There IS a self test circuit on the bike that uses the fuel gauge to blink out an error code. I suggest you check the shop manual for that. If you do not already have it, you can find a free download for it in the tech library.

Goose

[bkuhr]

Not familuar with RSV, but my first thought would be a missing or bad conection of a dedicated ground wire from good frame ground to the unpainted metal of the sendor unit itself. Maybe the open circuit is also causing the error code.

[V7Goose]

OK, I just checked the shop manual, and the section on the self test is quite unclear, so I made some checks on my own bike. Here are some simple tests to help you isolate the problem.

 

When you just disconnect the sender plug on the front of the tank, the fuel gauge should flash all bars after the initial set when you turn on the key.

 

Using a volt meter, check the voltage from the Green/White wire (female pin) to ground with the key on. It should be 10-12 volts, depending on the current battery charge. Remember that with the key on but engine not running, the voltage will be pulled down quite a bit by the lights, so less than 12 volts is not an issue.

 

Now use an ohmmeter to check the resistance on the tank plug between the Green wire and black wire - with a full tank it should be around 8 ohms. I do not know what it will read empty, but there should definitely be some continuity. If it is completely open, the sender is bad.

 

Next, check the resistance between the Green/Red wire and black wire - it should read around 1.2 Kohms. If there is no continuity, then the thermistor is bad.

Goose

[BradT]

All the bars on my fuel gauge blinked a few times, then only one bar blinking on the empty mark. I pulled it out the sending unit and one wire was broken off and it could have been re-soldered.

 

Very easy to check after draining most of the fuel but you may want to replace the gasket when checking it. You can actually check it with a multimeter, with out removing the tank.

 

Brad