Well after my last Engine temp sensor fix and TPS reset, I was riding awhile on about the hottest day ever, and after the 30 min I was heading back through the hills when the bike became sluggish then quit running, It did show a TPS code but I also no longer hear the fuel pump priming at all. Towed it home and trying to diagnose.
I am starting at the connection to the pump at the fuel canopy lid. When I turn the switch, I see a very brief flash of over 12V, a very quick flash of 11.9V, then within a second or so voltage drops out. Same at barrel connection near seat. I am wondering if this is a relay problem , but it has never been handled.
During the ETS diagnosis I did verify pump and filter function, they were replaced when I got the bike a few years back.
My TPS still shows the same voltage reading as when I checked it recently that allowed it to run.
I did buy a nice Honda XR250R and brought it home so thee could be some wicked jealousy from the RK, but geez, I been so good to her, seems out of character.
Maybe couples therapy, I dont know......
You report that bike became sluggish and quit running...That makes me think fuel related.
You no longer hear the fuel pump priming at all...The fuel pump would normally cycle for a few seconds and then turn OFF until engine is running.
You towed it home and tried to get a diagnosis. You started inspection at the connection to the pump at the fuel canopy lid. When you turned the switch saw a very brief flash of over 12V, a very quick flash of 11.9V, then within a second or so voltage drops out.
Same situation at barrel connection near seat.
Again, it makes me think fuel related.
Try powering pump directly..perhaps pump it is stuck...or wire is broken.
While it is possible that a relay could be the problem the probability is not high unless a rubbed wire happened during a pump change and that wire rub got worse. During the ETS diagnosis you did verify pump and filter function, they were replaced when you got the bike a few years back...a broken wire at pump could be a probable cause.
*It reads like a fuel related issue but is it due to a pump failure or failure of power getting to the pump?
*A larger piece of fuel tank liner blocking fuel filter sock would reduce fuel flow but a total shut off would not be common.
On a side note:
*I will take a guess that you have reviewed the CRANK position sensor connector that is about a foot away from computer..A loose plug and turn connector would cause a shut-down and no restart...lots of cranking..but no start..
Located behind the painted side cover, near under seat area... along frame triangle..throttle side..
CPS connector seems fine, and if it was not I think I would still hear the pump prime. Still haven't located info on the fuel pump relay, except that it may be behind the ECM.
Can I use a jumper wire from Battery positive to the single connector on the fuel tank canopy to apply voltage directly to the pump? Thanks.
I just did more thorough volt test at the pump wiring barrel connector near the seat and found
not a flash of battery voltage, but perfect battery voltage when switched on, lasting for about as long as the pump would normally be priming.
The voltage is good all the way to the connecting tab on the tank canopy.
Pulled the canopy to find the Battery positive connector separated from the body of the aftermarket pump, sprung loose indeed.
(i think it might be the ALL ***** pump, looks like it but i gotta check my records from a few years ago)
Pretty bad failure but at least we know what left me waiting for AAA
That is something special.
Great job at diagnostics.
It looks like the constant vibration of motorcycle, plus the working vibration of pump and the addition of the spring pushing against the connector caused a major disconnect.
I have not seen that reported.
Makes me wonder if somehow an additional "strap" can be added when pump is replaced to give greater support over that whole area.
*Why was the previous pump replaced?
*The fuel pump relay is listed in service book on page 5-14...of the 4 relays by battery. The fuel pump relay is outside edge (throttle side)..
It goes from right to left....Fuel pump (outside edge), ECM power(has torx screw for battery hold down), then starter, brake (the other outside edge)
Photo of how the brush pulled from the fuel pump would help to see if just epoxying it back in will solve the problem or not, but have been running a Quantum fuel pump for years, in the hottest of heat without problems. Hence did the fuel pump/filter/pressure regulator all one go years ago, to just get them out of the way before they became a problem, since was already in the tank to change the filter out to start with.
The trick on the Quantum fuel pump fuel pump since its shorter and fatter than the oem pump, take the factory fuel pump bottom rubber insulator from the old pump, turn it upside down, and use is as the top spacer for the fuel pump in the plastic carrier body, to hold the fuel pump all the way down in the carrier.
Can only imagine that the top cap plate that is sonic welded, let loose to cause the problem and would get a call into all ***** to have them replace the defect fuel pump. Yes, maybe some epoxy would fix it, but petrol has a way of effecting some epoxies, so really don't see that as a long term fix (maybe JB weld would work better)
Hence on both my oem pump, and the replacement Quantum, normal for me to take the tank down until my fuel light comes on (set it when I had it apart to fix it to come on with 50mile left in the tank so fuel is less than half way up the pump), so run mine my tanks low before refilling low like guessing you are doing as well, but have not had the pumps do melt downs. But will note, that I have my RK 97 with EV13 cam and screaming eagle K&N air filter, slightly raised compression by facing bottom of jugs to get squish to .030" for both jugs, tuned much richer that HD would ever tune with Dobeck gen 2 pot type tuner (fuel is cooling), to min the amount of times that the engine has boiled the fuel in the tank from sitting at a stop light too long in summer heat to start with.
If your looking for the same to just add a touch more fuel to get the engine temps lower (again, fuel is cooling, and HD tuned the motor way, way on the lean side to start) then keep you eyes open for a used Dobeck 950141040 tuner on ebay or other sites (got mine for $49 used off ebay years back), https://www.tficontrollers.com/Cruis...ct.asp?pid=140
Yes, it going to cause the engine to run even more richer until is motor comes up to temp to switch out of cold start up mod, to normal temps, since its adding fuel across the board, normal engine temp and even during cold start up a well. There are some tuners that do a better job of getting into the ECM table to adjust both the cold tables, and the normal warmed up tables, but your talking well more than $100 in the end instead (and someone that does know now to tune a MM ecm with the needed software as well. In case of want to go that way, then look for the discontinued S&S MM replacement ecm, with the tuning software for it, as well as scanning software as well, is free. https://www.sscycle.com/racing/support
To sum it up, may have just been sonic welded defected fuel pump to start with, but before tuning my RK richer (even before modes), number of times that the tank would just boil the fuel from motor heat from how lean HD had is tuned, and guessing that this may contributed to the problems with the Fuel pump breaking any sonic welding bonds to start with.
06-26-2024, 11:04 AM
98 RK quit fueling
