I was instructed to start a new thread, so here it is.
If you own a Power Commander 5 for your RC51, have you ever noticed weird surging or power fluctuations around the 5000 RPM range? If you have the auto tune, have you noticed that the trims will excessively lean the 4500 - 5500 RPM range? If so, read on! I'm looking for individuals who are using a Power Commander 5 (AKA PCV) on the RC51, who are willing to run a simple test to see if your PCV is having the same issue I have run across on two separate bikes with two completely different PCV units.
Long story short, I purchased a PCV about a year ago (Sep 2014) with auto tune. I added the O2 bungs, installed everything and was off and running, only... it wouldn't run right at certain RPM ranges. I tweaked, adjusted trims, fiddled, advanced the map, demoted the map you name it, I tried it out. What I finally discovered, is that the PCV has a fundamental problem where I "believe" it is receiving RF interference from the bike, causing the RPM to bounce 400 - 800+ RPM with a constant throttle position. The issue is most common around 5000 RPM (+ or - 300 RPM) but I have also noticed the same issue around 3500 and 6500 (give or take) though it is nowhere as severe, it still causes problems.
The problem with the RF interference (to my best guess) is that it causes the PCV to begin pulling fuel from not one cell, not two cells, but across three different cells simultaneously if you're on the 500 RPM map. Drop the map to the 250 RPM and it will try compensating for 6+ different cells. If the PCV is trying to pull fuel from more than the target cell at the exact same time, what do you thing is going to happen? Well, when the auto tune is hooked up, it freaks out and goes "whoa! That's way too much fuel!" so it leans out all of the problem cells, regardless of what you have dialed in for your AFR value. If the AT isn't hooked up, it doesn't matter WHAT you plug in for fuel values because the PCV is trying to give the bike too much fuel (if you have a downloaded map).
See the problem in action:
So, in order to test the issue, hook your bike up to a computer, fire it up and begin revving it while in neutral. (You're gonna piss the neighbors off) When you get around 4800 RPM, begin slowly increasing the throttle. If the PCV is working properly, you should see the RPM bounce approximately 40 - 80 RPM. However, if it has the same problem as I have discovered on two different PCV units across two completely different 03 RC51's, you will notice the RPM bounce around, way beyond the 40 - 80 range. As you move past the trouble area, it should clear back up. The problem area is usually only in a window of about 100 RPMs but within that area, it will be very noticeable if it's acting up.
Problems with DynoJet
DynoJet is aware of "my" situation. I can't get their warranty manager Stan Lass to call me back, even though I started the issue with them back around March of this year (2015). I've spoken to those guys countless times and I've only spoken with Stan twice, despite multiple promises that he would call me back from various people. The last time I spoke with Stan around the end of July, he sent me out a second PCV unit to test (same issue). I can't get a hold of him to find out if he wants it back and since it doesn't work, I can't even sell it out from underneath them (not that I would...). I'm at wits end and finally biting the bullet to ask for help from the community to get enough people to test and hopefully confirm that it is an issue that needs to be properly and professionally addressed by DynoJet.
Note: The problem does not appear on a Power Commander III, only the PCV. Changing the PCV negative location from the battery to the frame, does not help. Adding filters around various power wires, does not help. I was informed by Stan from DynoJet that the PCV runs on a lower voltage than the PCIII, so it might be more susceptible to interference. DynoJet thought maybe it was a stuck injector. The way you can check for a stuck injector, is to watch the "Duty Cycle". Normally the Duty Cycle will increase gradually with engine load. If the injector is sticking, you'll see the duty cycle spike way up to a crazy high %, then drop back down to normal. In my testing, the duty cycle remained fairly constant at 10% - 15%.
Several things need to be determined if we want DynoJete to look into this:
1) How many others are experiencing the same problem.
2) What years are being affected? (SP1? SP2? Both?)
Current Update as of 11/11/2015
If you haven't been following this thread and don't feel like going through its entirety, the current "fix" for this problem is to run a Power Commander 3 inline first, then the Power Commander 5. Yes, you will need to run two power commanders to currently fix the problem. The PC3 does not suffer from the RPM bounce problem and cleans the fuel injection pulse, which then sends it to the PCV. So, ECM -> PC3 -> PCV. In theory, it doesn't matter what values are in the PC3 tables, however it is recommended to zero all of the tables.
If you don't have or want to run a PCIII, then you do NOT want to use the AT (auto tune) system as this amplifies the problem and can potentially create dangerous scenarios. If you do not wish to run the AT system and you also don't want to run the PCIII, then it is highly recommended to run your base map at 500 RPM instead of 250 RPM which creates a smaller window of error for the problem to amplify itself. Drive ratio gearing (sprocket teeth changes) can also affect the perception of the problem. By changing the drive ratio, you can move the problem window into RPMs where you are not doing static, constant throttle cruising. There are no suggestions for magic ratios at this time.