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2004 RTP, Funny fuel level indicator issues

skinny_tom (aka boney)

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skinny_tom (aka boney)

I'm posting this for a friend whom I've been helping sort issues. Strangely he turns to the internet for information at the drop of a hat but has some kind of issue with actually signing up for the board. Who needs an account when you've got friends to do it for you, right?


So here's the issues as specifically as I can:


Bike; 2004 RTP


The RID indicates proper fuel level when the ignition is on and the engine is not started. Unlike my bike, which immediately indicates fuel level, his takes a second or two for each bar to appear as the level crawls up the display.


Once the engine starts, the fuel level indicator resets to zero and never comes up.


He has: replaced the fuel level sender and replaced the "indicator damper" plug relay-looking thingy in the fuse box. Prior to this, the fuel level indicator didn't work right at all.


While trouble shooting, and looking at the 2003 civilian model wiring diagram, we've covered some interesting things and here they are;


(first, the diagram is close but not a match.)

*Other parts of the RID work correctly.

*The current issue is repeatable 100%.

*All fuses and relays work properly.

*Once, and only once, the ABS and whizzy brake system shut down while on a ride (right at the end) and works properly now.

*The ABS system and fuel level indicator system work off the same circuit pinout from the ignition switch and the same ground (according to the 03 digram) We've fairly thoroughly tested the ignition switch and associated wiring without findings.

*This one is key, but we're not sure how: If the fuel pump replay is pulled, or the fuel pump fuse is pulled, the RID instantly shows the proper fuel level when the ignition is turned on, just like on my properly functioning bike. Obviously we can't start the bike.


So, a few questions for ya'll while he's at home taking the bike apart looking for the ground lead.


This sounds like a bad ground to me, but I can't get past the fact that it works right when the positive side of the power to the fuel pump is disconnected. Perhaps there's a short?


Is it possible the fuel level sender is grounding through the not-running fuel pump motor, and when it runs there is no ground? If so, how does this not also effect the ABS system (unless perhaps it's grounded by it's body to the frame?)


Can anyone provide the proper relay locations and fuse locations for an 04 RTP? They're definitely not the same as an 03 civvy model.


Anyone else have some thoughts on this?

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Morning Boney


With the bike being an RT-P all bets are off on ANY electrical issues.


I agree with you in that the first thing that comes to mind is a poor ground or cross talk between the pump ground and fuel sender ground. Check the resistance between the sender ground side and chassis ground then between sender ground and battery (-) post. If not close to the same there is ground resistance issue somewhere or from chassis to battery (-) somewhere.


Being an RT-P who knows what was done to that bike electrically during it’s duty life or as it was de-commissioned and things removed or deactivated.


I guess if I were looking for that problem I would first use an ohmmeter on the pump ground and then the fuel sender ground (starting at connections inside the tank), then disconnect the grounds and see if there is any continuity between the two.

Maybe try adding a new temporary ground to the fuel sender low side directly to the battery (-) post.


Otherwise unplug the fuel level sender and place a voltmeter across the plug, then run the pump and see if any voltage change across the level sender terminals. Then check for voltage from sender ground side to battery (-) post with and without the pump running.


If nothing found in the above maybe look for some other accessory spliced into the fuel sender circuit or a grounding or power cross talk at the RID itself.


Maybe save a lot of fiddling if the fuel (level) sender in the tank is eliminated for testing (save removing the tank at first) by unplugging the tank connector then jumpering ONLY the pump to the wire harness then jumpering a fixed resistor across the fuel level terminals to spoof a fixed fuel level. That way if the problem is not evident as indicated in your post then the problem is more than likely inside the tank. If no change in problem then more than likely external to the tank like a remote ground area or cross talk in a circuit somewhere.


Maybe make sure the fuel return (inside the tank) isn’t squirting fuel directly on the sender therefore messing with the float position. Difficult to believe with that tube type sender but who knows what was done when that bike was in service or de-commissioned.



Just be glad he isn’t paying a dealer to find this problem as that could get real expensive at $95.00 an hour.



Added: I should have mentioned to also check the ground integrity on the “fuel level dampening” both with the pump running and not running.

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