Bad Fuel Sensor?

[OlGeezer]

I went out on a little day ride on Saturday and, towards the end, my fuel gage started going whacky. Right after fillup (within about 20-30 miles), the gage dropped to half full then, within about an hour, it would go to zero. I filled up in Baker, CA on my way to Parump, NV, it was half full at the Shoshone turnoff, a mere 60 miles or so from Baker. By the time I got to Parump, I only had about 3 bars. On the return, it really didn't go below three bars all the way back to Baker where I filled up. My next tank was even worse as I said, half full after about 20 miles then quickly to empty even though it's only about 180 miles from Baker to San Juan Capistrano.

 

I don't think it's the RID, but it could be. How do I check the sensor other than just replacing it?

 

Thank you,

 

 

[dirtrider]

Afternoon OlGeezer

 

What you working on? Is it your 1150RT?

 

If so you can check the sensor but it is a lot easier to check the RID and it’s wiring.

To check the sensor you either have to remove it (requires tank removal draining) or TRY and measure the resistance at the tank exit connector while you vary the fluid level in the tank.

 

Tell us what you are working with so the info we furnish is accurate.

 

 

Added: you aren’t getting a vacuum or sucking sound when you open the filler cap after riding a while are you. If so suspect a plugged tank vent or evap can that is allowing engine vacuum to suck the sides of the tank in.

[OlGeezer]

Sorry. I thought it would be obvious that the problem is with my 2002 R1150RT. Bad assumption on my part. Since I live in California, it has the California emmissions package. The original canister is intact.

 

No sucking sound or resistance when opening the fuel cap.

 

Thank you,

[dirtrider]

Afternoon OlGeezer

 

I kind of thought it was on your 02 RT with reference to RID & all but this way there is no guessing (you could be working a new bike or someone else’s bike). Wrong info is worse than no info.

 

No California emissions on your 02 RT, all U.S. imports for the 1150RT were 50 state legal including cat & evap can.

 

Now the bad news for you, at least from me for now. .

 

I am no where near my shop right now & won’t be for a while. I don’t seem to have an 1150 RT wire diagram on the small travel laptop I have with me. SO, hopefully someone will see this post & give you correct wire color info.

 

You can probably test the RID by unplugging the wire harness going to the fuel tank, then with the with key on insert a 0-20 ohm adjustable pot between the fuel gauge reading wire & the brown tank ground wire (motorcycle side of harness for the testing) . You should be able to cycle the RID from full to empty with the pot. OK, here is the wire color I don’t have for you—that is the one from the tank to the RID. On an 1150 GS it is kind of a greenish- purple-violet but I sure can’t remember if the RT is the same or not. I also don’t have the connector socket number of that wire. The connector should have a Brown ground wire, a fuel pump power wire (about 3 seconds with key first on), a wire going to the needle dampening for the low fuel light & the fuel gauge wire going to the RID.

 

 

If you figure out the fuel pump power wire you can’t hurt the other ones by grounding them as the brown is already ground and the other two go low to effect the low fuel light or RID fuel gauge.

 

 

 

 

 

 

 

 

[oldyam]

HI DR

 

I only have one diagram for the 1150 RT and that shows the wire to be Yellow / violet trace going onto pin 8 0n the RID connector.

 

I hope this helps

[dirtrider]

Afternoon oldyam

 

Yes, that’s the one it goes to pin 8 on the RID.

 

[OlGeezer]

Thanks, Dirtrider. I'll try to follow along. I'm new at this. I'm assuming I can get the 0-20 ohm pot at Radioshack?

 

I'll start pulling it apart tomorrow. I've got to do a service anyway (13th level 2 service for those who are keeping score).

 

[skinny_tom (aka boney)]

Oh boy...

 

Electrical issues.

 

I just finished helping a friend figure out the issues with his 04 RTP's gauge. It would never show full and creep down to empty prematurely. The odd thing? The low fuel light (on a different float) worked perfectly. It turns out that there is resistance in the ground wire feeding his tank. The short term solution was to run a separate "clean" ground lead to the small ground wire found on the tank side of the electrical connector that you have to disconnect to get your tank off.

 

Don't know if this will help you, but you might try jumping a clean ground to that wire and see what happens before you tear into the entire system multiple times like we did.

[OlGeezer]

Oh boy...

 

Electrical issues.

 

I just finished helping a friend figure out the issues with his 04 RTP's gauge. It would never show full and creep down to empty prematurely. The odd thing? The low fuel light (on a different float) worked perfectly. It turns out that there is resistance in the ground wire feeding his tank. The short term solution was to run a separate "clean" ground lead to the small ground wire found on the tank side of the electrical connector that you have to disconnect to get your tank off.

 

Don't know if this will help you, but you might try jumping a clean ground to that wire and see what happens before you tear into the entire system multiple times like we did.

 

Thanks. Just curious, but what is the long term solution?

 

 

[Les is more]

On my 02 RT in was corrosion in the electrical connector. Some contact cleaner and dielectric grease cleared it up.

[OlGeezer]

On my 02 RT in was corrosion in the electrical connector. Some contact cleaner and dielectric grease cleared it up.

 

Les - you know, I've had to apply this treatment in the past, but the fuel gage was never THIS bad, so I was CERTAIN I must have some sort of catastrophic failure. Still, cleaning the contacts is a fairly simple procedure once the panels are off. Amazingly, that's all it needed. While there, I did test the connectors with the pot, but I must have used an incorrect resistance range. My gauge was full on when connected.

 

One problem down, two to go (high beam and trip meter reset).

 

Sigh...