My 2010 Road King has had a sporadic sputtering problem now for almost a year. Sometimes it will get so bad that the check engine light will come on and the bike will cut out at stoplights. It will sputter and hesitate at low speeds and at highway speed. I thought that it was an issue with fuel delivery, a fuel leak or air leak. The first time I brought the bike to the dealer, they replaced the intake seals because they were sucking air. The 2nd time I brought it to the dealer, they replaced the fuel filter and tested the entire fuel system and they told me the fuel pressure was at factory specs. The 3rd time I brought it in was last week and they retested the fuel system and the pressure was fine, no leaks and no codes were stored. The technician said the bike rode fine and he couldn't feel any sputtering at all. When I picked up the bike, it did perform fine.

Now today, at initial start up and for the first 10 - 15 miles the problem was there. I stopped for about an hour and when I re-started and rode the bike, it was fine no sputtering. Then I stopped for a couple hours. When I restarted the bike, the fuel light came on and the range said Low even though the fuel gage was at 1/2 tank and when I visually inspected the fuel inside the tank, it was at a 1/2 tank. I rode about 30 miles home with sporadic sputtering and when I filled up the tank about 2.5 gallons went in. When I restarted the bike the fuel light was off and stayed off.

So the fact that in the same day, my bike will perform differently after each start-up and that I'm getting warning lights coming on and off has led me to believe that the problem lies in the ECM. I've had a Stage 1 download done when I first bought the bike in '09 and then when I put new pipes on the bike about a year and a half ago, I had the bike tuned with the Screaming Eagle Race Tuner.

They haven't found any fuel or air leaks and the bike has sporadic sputtering, what could be the problem?

Any advice is appreciated!

-Alex

 

Have you checked the TPS connector behind your intake? I had a similar issue, pulled that plug apart, threw in some dielectric grease, and snapped it back together good and tight. Haven't had a repeat of the issue in over 2 years.

Might be worth a shot before dropping serious coin on an ECM. Good luck!

 

I know it is a simple thing but check the battery connection.
It will make odd problems like this. Other power connections that are not secure will make similar problems.

 

You may also want to inspect the ECM plug contacts for fretting corrosion and throw some dielectric grease in there. I'm not familiar with how the SERT connects to your ECM but I assume it's in series with your ECM. If so, inspect those connections and throw in some dielectric grease as well.

+1 on R Hill's comment on battery connection too. Check your battery cables for tightness.

Do a search for "TPS Connector" and you'll find a lot of info on your issue.

 

I cleaned the TPS plug behind the air cleaner with contact cleaner and the problem is still there. One thing I noticed today while riding is that I'll be stopped with the bike in neutral and idling then the RPM's will drop slightly for a a couple seconds like the engine is about to cut out. Immediately after this happens, the check engine light will come on and remain on until I shut the bike down. When I restart the bike and start riding, the check engine light will remain off until the drop in RPM's happens again.

-Alex

 

Disconnect your battery for a while then reconnect and see if that helps. Also, make sure that your o2 sensor plugs are dry and clean.

 

Ok, I'll try disconnecting the battery. This might sound dumb, but could using a Battery Tender cause any of the problems I'm having??

 

not unless the tender pigtail is causing a loose connection.

instead of removing your battery cables - check them for tightness, then pull the maxi fuse (usually orange, biggest fuse in the panel). also, definitely check the TPS and ECM plug like they said

 

Don't forget the 15Amp ECM fuse, it comes after the Maxi fuse.

Look for the "RIGHT GROUND STUD" connection that has a Black/Green wire. This is the CLEAN ground wire that connects to the fuel sender, the ECM, the console harness interconnect and other equipment.
Then the "LEFT GROUND STUD" called DIRTY ground is the connection between battery and frame. If you have poor contact between both grounds you have a problem.

 

I am gonna guess weak spark, maybe the coil is getting bad, or the plug wires.