Hello, I bought a 2003 FLHTI this summer and rode it around for about 1500 miles. Since it got cold I purchased some new performance item for it and installed them last week.
I have PCIII USB, Stage 1 K&N Air Cleaner, V&H Dresser Duals and Screaming Eagle Mufflers. I installed the closest map to the PCIII M807-033. The bike rides great under load and only slightly backfires on decel. But running at idle and revving it in neutral(no load) it seems to be backfiring from the rear cylinder. I have been told to increase the fuel trim on #1(rear) cylinder and posibly use the button to richen the map in all ranges. I am still not sure this isn't a misfire and I haven't had time to hook up my laptop out in the cold garage. I am new to the Harley world but have been an auto tech for 25 years. I know these bikes have a crazy idle, but I never noticed this much difference between cylinders before taking off the factory crossover pipe.
Has anyone had a similar experience????
I just ordered new plugs and wires because I am not sure how old they are, but again it seems to be only since mods?? Is it possible to have a bad PCIII??? I got it used??
The mods look awesome, but it seems to be running uneven.
Any ideas would be appreciated!!
Thank you and Happy Holidays!

 

Every thing sounds normal but i always like to check for a intake leak, if its sound thier. you should just need to adjust the 0% throtle front and rear cylinder.....hook up your cp and using the pcIII software, enter in both front and rear(fuel table 2 and 1) a -25 in the 0% tp colum from 2500 to 6250, if that dosent work put in a 25. play around in those ranges you cna safely go from - 50 to 50 mut i never need to go that far. Dont Mess around with the external buttons, all you will do is lean or richen you map out, and it is very unlikely that youll be able to get the decel pop out.

 

When I installed the PCIII the Throttle positions, Idle and WOT were set. I just haven't played with throttle trim yet.
Thank you I will be playing with it soon except the weather is calling for my plow not my bike!

 

sounds good, but just so where on the same page, what are you calling throtle trim?

 

The difference in the 2 cylinders in a Harley Vtwin engine can be dramatic. If you don't believe it just hook up a vacuum guage to that sucker and be amazed. If you are doing a stage 1 on your bike and using a PC then I would recommend you find a good dyno tuner who has lots of experience with PC tuning and have the bike custom tuned and both cylinders synched. He should tune and time each cylinder seperately. If this is done correctly you will think you are riding a different bike when complete. That said, do 1 check first. Disconnect your PC and see how it runs.

 

Looking at map 807-033 this should be a good starting point for your setup, however there are a few other area I would look at first. I first recommend checking/resetting the throttle position settings, here is a video that will explain this step by step http://fuelmotousa.com/SetThrottle.swf Second I recommend updating the firmware or at least making sure the firmware is version 2.2.2.0 or newer. You can get the latest version here http://www.powercommander.com/downlo...ey_2.2.5.0.zip I would first check these two items. I do not recommend using the buttons as they are a broad range adjustment and will trim a 1/3 of the fuel map and I also do not recommend the cylinder trim feature as it skews the entire map for that cylinder, not just a certain area. As far as tuning individual cylinders this works very well, however without a dyno or a wideband datalogger it would be simply guessing. You can also easily adjust the decell area in the fuel map for your decell popping and I would also check for an exhaust leak at both the joint and at the heads, as well as checking for an intake leak at the manifold as this is becoming more common as these bikes are getting older.

 

The more I read here I am thinking I do have a misfire. The popping is at idle throughout throttle motion from rear cylinder only. If I hold it at 1200 rpm I have a slight misfire/backfire. If I hold it at 1500 same...and so on.
I ran the bike last night and noticed the engine light came back on and went off again, which I believe means I have a code stored now. I will be checking the code tonite if I get a chance. I will also check for intake leaks. I just never heard the rear/left pipe before changing to true duals, and I keep reading about people having problems with EFI bikes.
I am going to try unplugging the PCIII also to see if it corrects the idle miss or not. I have to rule out each piece now I believe.