Assuming the fuel pressure is correct (I am not assuming that as the dealer completely shotgunned this with guesswork) has anyone visually inspected the throttle shaft for being broken at the screw closest to the TP sensor?

 

I had a ton of family events pop up over the last month, so I was just now able to get back to looking at the bike.

I kept the tuner since it did help a bit.

I started checking for intake leaks, but haven't been able to find anything yet. I only had enough time to remove the filter this past weekend but will get back to it sometime this week. However, I was able to get a video that is a good representation of what the bike is doing. I took off the air filter and the bike backfires out the intake every so often. I tried to get a video from a cold start, but I messed it up so the bike had warmed up a little bit (which is why it isn't totally dying in the video). You can see the explosion in the video, but you can't see the "puff" of smoke it spits out through the throttle body when that happens.


@MyFavRk My bike does have a rubber cap, but it seems to be in good shape. It's on there pretty good. Been checking the intake seals, but haven't gotten far enough in there to say for sure I can't find anything.

@Ed Ramberger I checked the throttle shaft and it isn't broken (visible in the video). The dealer told me the pressure was correct, but I don't know how to verify this myself.

 

Now I'm intrigued to find out what the solution is going to be.

 

Regarding Ed’s question about the throttle shaft, it is not visible in the video. You would have to open the throttle and look at the shaft itself- not the butterfly. I’ve seen several ‘06 shafts break at the screw locations.

 

Still wondering if it may be the crank sensor , did you check the connections ? usually when doing oil changes , if your not careful , oil can drain down from removing the oil filter and coat the connector mounted under the frame ( along with the regulator connector ) , may want to unplug those connectors and give them a good cleaning with electrical contact cleaner .

I haven't ruled out a faulty crank sensor .

 

No combustion dtc in my experience comes when:
Bad injector-wiringLean conditionBad Spark plug wireNot oem Spark plug resistance (no power issue)Bad Power supply( ignition switch leave when hot/ battery cables/bad ground terminal)

 

Normally I would say after checking everything, I'd check for water getting into the carburetor, but you have that new fangled throttle body, computer controlled stuff. So if water is getting into your fuel system, it would likely be in the tank, imo. Try switching to reserve and run it that way for a bit, then switch back and see if there are differences in idle. Gas floats so more water would be down in the reserve area of the tank.

The other option is to drain the tank into a large glass jar, like a pickle jar. Then let it sit and see if water separates out. Sorta like what pilots have to do in their pre-flight check. If you do this, make sure to drain with the petcock set to reserve. Also, don't do this around flames, sparks, or smoking, etc. Plus not in your garage with gas furnace or heater, or dryer for that matter. I'd do it outside.

 

If check engine light comes on intermittently, I'd suspect it's sucking air from somewhere (intake gasket, etc.). I had a similar problem w my 05 Softail, & others, & found it was a compound issue. Prior owner was original owner and did zero mods/upgrades & likely little maintenance. I replaced both O-Rings in the QD Check Valve (a well-known issue), which helped (engine check light stayed off) ethanol & additives will dissolve these older O-Rings (new ones need to be made of DuPont 'Vitol'. Still had a stutter so I drained the fuel tank & let it dry, again (no rust or sediment). This ensured any/all additives, water, particles, old gas, impurities were removed
If bike sits for 6+ months, fuel will begin to gel & cause misery (once gelled, it can't be fixed by additives, afterwards). Backfiring is "only" caused by "bad timing" (incl plug gaps, wiring, etc.). Gasses ignited at wrong 'time' is self-evident, but a reminder can't hurt.
I had 14k miles on bike, but I figured all parts were 17 yrs old. I replaced spark plugs ($12) & gapped at .040, not great so went to .036 & better.
Then checked the bike at night while idling for 'jumping sparks', looked okay, but replaced 17 yr old plug wires for $3. (Auto Zone surplus) & helped a bit.
It still has some hesitation at low rpms w occasional misses at speed so I'm suspecting fuel system (usually is) & will change Fuel Filter again & Air Filter + internal tank hoses, which develop tiny leaks (known issue) , regulator w housing, next week.
In 50+ years of doing my own wrenching, I've found it's usually something simple or a combo of simple things. So far, with this older bike, I haven't really done anything that wasn't due to be done anyway.
If I'm not happy w results, I'll probably replace intake gaskets next, during Winter. I'll go w the tuner only after "all the old parts" are updated.
Only thing I will 'ASSUME' is that, if I didn't replace a part, no one else has.
I have been stranded on the wrong side of the Rockies because a bad tank of gas restricted my NEW gas filter. It was difficult for me to suspect a "new" part.

 

I have gone through the same thing with my 05 night train efi, I changed the throttle position sensor and that seems to have fixed it after 2 years of trips to the stealership and every other sensor changed, I think mine was a combination of the tps and the ignition switch, now sometimes it starts and runs fine other times it will stutter and stall, but if I switch the ignition on-off-on 3 times it’ll start and run fine, I noticed that when I changed my tps, when I removed the 2 screws the old tps didn’t move, when I installed the new one the screw holes won’t lineup unless you rotate the sensor a bit, I hope this helps

 

The last posting was in October of 2022. Was there eventually a solution to the issue?