I spent a good amount of time here reading about similar symptoms but none exactly like mine so I thought I'd throw this out there..
Bought a 2007 Sportster 4Tec 215 SC, about 100 hours. Took it out several times, ran perfect, no problems at all. Was having difficulty and annoyance with the keys so I did exactly what I did with my 2 2013 RXP-X 260 SC jet skis, with the BUDS system, I deactivated the DESS. This had no ill effects on the skis whatsoever. Not so lucky on the boat. I hooked up the BUDS, deactivated the DESS system, no codes, did nothing else. I wrote the new info to the computer and exited. I also changed the plugs. Right afterwards, I'm having problems and I don't know if it's related to something I did while deactivating the DESS and writing to the computer but it started immediately afterwards. The boat starts fine, idles fine and accelerates fine. I reached about 35mph cruising speed and I noticed more of a rich mixture exhaust smell than I did previously. I began to feel surging at all RPMs. Then while holding a steady speed, I get a muffled backfire, through the exhaust I guess, I'm not sure. It's not huge, sometimes just barely noticeable, other times very apparent. Does this through most of the RPM range. It happens cold and at run temp. Sometimes it's perfectly ok for a few miles and then it starts surging and backfiring. The backfiring is no steady, just once or twice until I change the RPMs. I can bury the throttle and I go right up to max speed, showing around 63mph on the speedo (I know, and I do take that with a grain of salt). At full throttle, it seems to run without surging or backfiring. I thought I had gotten some bad gas, even though I used the same gas to fill my truck's tank and no problems with it. I ran most of the gas out of the tank and filled from a different station, no luck. I changed out the NGK plugs, no luck. Since the boat ran perfect before, I'm having a hard time thinking something went wrong all of a sudden. If that coincidence happened, I'm going to play the lottery! I don't want to start throwing parts at this although I know that might be the only way. I do have the repair manual and the BUDS setup but if there are no codes, which there weren't when this first happened and I checked for them, I'm baffled. I can't help but think I did something when I used BUDS and I haven't checked yet to see if it saves the old settings file so I could try to go back to it. Like I said, I only disabled the DESS system, nothing else.
Thanks in advance for any insight you could give.
Bought a 2007 Sportster 4Tec 215 SC, about 100 hours. Took it out several times, ran perfect, no problems at all. Was having difficulty and annoyance with the keys so I did exactly what I did with my 2 2013 RXP-X 260 SC jet skis, with the BUDS system, I deactivated the DESS. This had no ill effects on the skis whatsoever. Not so lucky on the boat. I hooked up the BUDS, deactivated the DESS system, no codes, did nothing else. I wrote the new info to the computer and exited. I also changed the plugs. Right afterwards, I'm having problems and I don't know if it's related to something I did while deactivating the DESS and writing to the computer but it started immediately afterwards. The boat starts fine, idles fine and accelerates fine. I reached about 35mph cruising speed and I noticed more of a rich mixture exhaust smell than I did previously. I began to feel surging at all RPMs. Then while holding a steady speed, I get a muffled backfire, through the exhaust I guess, I'm not sure. It's not huge, sometimes just barely noticeable, other times very apparent. Does this through most of the RPM range. It happens cold and at run temp. Sometimes it's perfectly ok for a few miles and then it starts surging and backfiring. The backfiring is no steady, just once or twice until I change the RPMs. I can bury the throttle and I go right up to max speed, showing around 63mph on the speedo (I know, and I do take that with a grain of salt). At full throttle, it seems to run without surging or backfiring. I thought I had gotten some bad gas, even though I used the same gas to fill my truck's tank and no problems with it. I ran most of the gas out of the tank and filled from a different station, no luck. I changed out the NGK plugs, no luck. Since the boat ran perfect before, I'm having a hard time thinking something went wrong all of a sudden. If that coincidence happened, I'm going to play the lottery! I don't want to start throwing parts at this although I know that might be the only way. I do have the repair manual and the BUDS setup but if there are no codes, which there weren't when this first happened and I checked for them, I'm baffled. I can't help but think I did something when I used BUDS and I haven't checked yet to see if it saves the old settings file so I could try to go back to it. Like I said, I only disabled the DESS system, nothing else.
Thanks in advance for any insight you could give.
