Well, now...

[Alister]

Just completed the installation of the TOR pipes, cat delete, fuel gauge, and clock... but now the fuel gauge has flipped out!

Driven it several times today after the install, and I noticed on the return from a little jaunt to the Exit 90 Chevron the fuel gauge had risen to well beyond the full mark. Took it back home, shut it off, then turned the ignition on again... and the needle went higher than before! I watched it closely and it seems the needle's wanting to keep right on going, as it will hit the limits of its movement and stay there, bouncing, for a few seconds before steadying out with the tip obscured under the uppermost rim!

It's really a no-brainer to install 'em if you keep to the instructions; all the connectors are right there, ready to go. Just a plug-and-play operation. More trouble to route the wiring correctly than anything else.

Not really sure if this is gonna be a warranty fix or not, as I installed the gauge myself, so I'm looking for suggestions. It's cooling off right at the moment, but I'm going to pull the tank so I can get a look and see if the wiring didn't get pinched somewhere.

Better yet... anyone got the resistance specs and wiring diagram for the fuel sending unit circuit?

 

[Molinoman]

Not sure

If the gage was installed by the dealer it would be covered under warranty and/or the dealer would adjust. Since it was a self install the dealer may charge labor to "adjust".
A good question. The good dealers already know how to adjust the gage so that it is "close" as far as when the tank is at around 140 milwa of use. This usually means that you have around 50 to 60 miles of reserve left. My fuel gage is just under the bottom part of the red zone nearing empty when the fuel light comes on. While in Nashville I was getting pretty decent mileage and the light never came on as I was filling it around that area on the fuel gage and was at the 156-161 mile mark on the trip odometer then usually I would only be able to add between 4.1 and 4.2 gallons of gas to the tank. At that rate I had about a 75 mile reserve left if I wanted to chance it.
Good luck.
Dennis

 

[Toystoretom]

I don't have a fuel gauge so I can't give you any resistance specs but I'll bet its a pretty simple circuit. A 12 volt feed with a ground that is varied by the sending unit in the tank.

If it is pegged all the way it sounds like you have a short to ground somewhere. Is it even possible to plug this into a incorrect connector? I would check both possibilities. The gauge itself could be bad, but I kind of doubt it.

If you have a DVOM you could check resistance in the ground wire. The only value I can give you is that you should have some resistance assuming that your fuel tank isn't completely topped off. If you have a half full tank and there are no ohms of resistance in that wire you have a short to ground somewhere, or possibly are plugged into the wrong connector.

 

[Alister]

Well... it actually kinda fixed itself. After I'd let it cool off, I decided to turn the ignition on and see what happened. First time, it came back down considerably, but still was high. Second time, it started reading normally again.

Maybe the heat? I have no idea.

Pulled the tank again, just to peek at the connector and wiring, and all seems just fine. Used my trusty Fluke 88 to check for a possible chafed wire (though it's brand new!) and shorts to ground-- nothing. So I took an extra measure and wrapped everything in some leftover spark wire heat barrier insulation I had sitting around, and zip-tied some of the excess slack up. Hasn't done it since.

But I'd still like to know what happened in the first place. Think my next purchase is going to be the factory workshop manual.


Oh... Tom? The preexisting connectors for the accessory fuel guage (four-pin, marked with blue tape), clock (three-pin), and grip warmers are all marked and unique to the accessory they drive. Triumph really made 'em idiot-proof!

 

[Toystoretom]

Triumph really made 'em idiot-proof!

Yeah... but I can be a world class idiot

I'm glad it worked out, but I'm with you, it would be nice to know what caused it in the first place. I wonder if there is a voltage stabilizer in that circuit like autos have. If so, that may account for the weird behavior. It may have to reset after you install the gauge. You can confuse the one in your car by filling up with the ignition turned on, it will never show a full tank until you turn the ignition off and let it reset. The reason they put those in cars is so that as the fuel sloshes around in the tank the needle in the fuel gauge won't go wacky. Newer cars have this item built into the ECM... it might be so with the Rocket also???

 

[Alister]

Yeah... but I can be a world class idiot

I'm glad it worked out, but I'm with you, it would be nice to know what caused it in the first place. I wonder if there is a voltage stabilizer in that circuit like autos have. If so, that may account for the weird behavior. It may have to reset after you install the gauge. You can confuse the one in your car by filling up with the ignition turned on, it will never show a full tank until you turn the ignition off and let it reset. The reason they put those in cars is so that as the fuel sloshes around in the tank the needle in the fuel gauge won't go wacky. Newer cars have this item built into the ECM... it might be so with the Rocket also???

I would assume there is one, yes. The gauge doesn't start flipping out when you ride along. Shouldn't have been necessary to reset anything, as the instructions tell you to remove both battery cables (negative first!) before doing anything else.

Still, it's not done it again, and it was well into the hundreds yesterday (you never seem to notice the heat off the #3 primary until it's already hot!). Problem solved? Despite the gauge working correctly, it's still not even remotely accurate. Think I need to see if Big Twin will do something about the sending unit.