Very strange problem with my Gen II (Updated with pics and info)

FZ1inNH said:
Update: Mostly solved! :D

I decided to try an experiment... thus far, it has paid off. It seems like the bike was definitely running with the aforementioned lean surge for sure. Because the bike operates in open-loop mode below a certain RPM and before the O2 sensor is warmed... Here is what I did. I disconnected the battery over night a couple days ago. I connected the battery and left for work after warming the bike up to 160 degrees. On the way to work, I ran for 4 miles straight at over 7500 RPMs. With the engine warm and sensors all working (now in closed loop mode) I was forcing the ECU to re-learn and map new fuel tables. This seems to have worked and has added the richer open-loop mixture back which was causing me trouble in the lower RPM ranges. I've had hardly any noticable trouble since this high RPM run and with the ECU running newly learned tables.

What this does tell me is that I've tipped the scale on modifications and will need either the PC III, PC V or the reprogrammed ECU. I think I will start saving my money toward the PC V and an autotune for it. It's either this or go back to stock and sell off all the mods. BTW, paypal donations accepted. ;)
Click to expand...

Glad to know it was the lean surge I suspected and it almost got sorted out. Sell off all the bling on the bike and get urself some performance and suspension goodness :D
 
NJFZ1 said:
It does sound like some tuning will be needed. Just get a PC V and forget about the Autotune...doesn't really work very well. I should know as I tried it and wasn't impressed. Short of getting the bike dyno tuned there are plenty of free maps out there as you well know.
Click to expand...

So what does a PC V cost? I'm kinda glad I have carbs. :)
 
As I was reading your stuff and saw you added a k&n I had a feeling it would get worse. All that extra air coming in with no more fuel is running lean hence the surging. Don't get the auto tune, they don't do anything. PCV and a good map and call it a day. ;)

I think your setup will rock once you get the Power Commander, and then you will have a smooth running bike. Personally, this is why I have done nothing to my bike power wise other than the slip on as I don't want to screw the already lean sided fuel mix that is setup from the factory. When I decide I need mo powa, which will not be for a long long time, then I will do the PCV and the supporting mods to go with it.
 
Last edited:
I'm still fighting what we're calling a "lean surge" issue.... Still unknown regarding the cause... but I have a question. Why, if my bike is running so far to the lean side, is my MPG so low now?

Before this issue started, I was tracking on Fuelly at around 35 mpg. Yesterday, I filled up and it was 32 mpg. This is after putting on the 17T front sprocket too which *should* have shown a gain (less RPM at cruising speeds).

I'm guessing I just need to bite the bullet and get a Power Commander but that's an expense I hate to incur if the problem still exists after I throw maps at it.

One thing my boss suggested is to swap coils around. I have not looked and cannot remember but who knows the Gen II firing order off the top? I can move the coils in a round-robin to see if it changes the surge. Hell, I could even "borrow" one from my wife and replace mine one at a time to see if it smooths out. ;)

Partshark sells the coils for $60 so it's not a horrible cost if this is the problem. They did test within spec though when I changed the plugs.
 
It may seem counter intuitive but there have been a number of reports from Power Commander tinkerers that leaning out the mixture (from a well performing map) in the quest for improved fuel economy often leads to the opposite. I doubt the issue is your coils . . . . . .
 
FZ1inNH said:
Before this issue started, I was tracking on Fuelly at around 35 mpg. Yesterday, I filled up and it was 32 mpg. This is after putting on the 17T front sprocket too which *should* have shown a gain (less RPM at cruising speeds).
Click to expand...

Don't get nervous with the MPG. Look at my fuelly, and look at the full thing. I have gotten from 28 to 42 mpg. All comes down to your driving, conditions, highway/city etc. Also, you went to the 17T. The take off with that sprocket could be using more gas as its a steeper gear from the initial go.

3mpg is nothing to worry about.
 
pjspin0331 said:
i don't know much about pc, what's the difference between a pcIII and a pcV?
Click to expand...

PC V is newer and has more "features". I like the fact that it's smaller and doesn't need the additional 9V battery to download maps to it or flash the firmware. Now that the Ignition Module has finally been released for the PC V I really don't see the point of getting a PC III. Also PC V has a 15% throttle opening table where the PC III goes from 10% to 20%. However, I'm not sure how much of a difference that really makes. Also the PC V form an '09 will work with the '06-08 bikes even though their website doesn't mention this.
 
Eric, sounds like the issues my brother was having with the Bee. I even think his coil's tested fine.

It ended up being his coils. Worth a shot if you have one to try.
 
Cobalt Coupe said:
Correct me if I'm wrong, but as far as I know, cooler temps and " better air " require more fuel to maintain a correct a/f ratio, so if it is lean surging at hot temps its going to be even leaner when it's cooler - nite time or early morning - so the problem would be worse when colder................unless the ecu is staying in open loop running off of fixed values, not sensor inputs which would get the ecu to try to correct the a/f.?
Click to expand...

You were correct here.... today was a different ride.

After all the heat we've been having up here and myself simply not finding a lot of time to ride, I was able to commute with the bike today. This morning was not so bad... mid-70's and it was acting up as normal. Then this afternoon, the temps fell and the ride home in the cool rain with a mid-60's temp really showed off the problem. In third gear, I was on a city street doing about 35 in traffic. The RPMs were about 3200... well, what a buck-board ride THAT was!?!? and this time, the tach needle was bouncing faster than a flea on a hot griddle. NOT a good time. Get it up over 4500 though and it (mostly) smooths out. I'm guessing I need to start back toward a stock bike until I can muster the funding for a Power Commander and get this girl fueled properly. This is not acceptable behavior. I tipped the scale at some point here from a great running bike to one that is apparently starving for fuel.... I'm still going to pull the coils and test them once more but with a more precise unit. Mine is a cheap suck-arse meter....

Anyone close got a PC that we can throw on my bike for a short ride just to be *sure* this is the problem??? I'm guessing with my mods, a Duken stage 2 map? Stage 3 would be more for a gutted cat or aftermarket header, right?

Argh............................................... :cry:
 
A PCIII or V may solve or minimize your problem, but I'd look for a mechanical problem before I spent the money on a PC. Not a lot you can do about the modded flys but going back towards stock is a lot cheaper even if it takes longer. The hard part is after mod has been added to mod, it's very difficult to measure the cobined affect they have on fueling. Even a sensor lke a MAP,MAF, or air temp can be messing up your mixture if it's on the edge but not throwing a code yet. You could be in for quite a test before yo get it sorted out. Having someone who has a like bike that you could swap parts with would definitely be ideal.
 
Sorry to hear you're still having these issues Eric, I believe alot of it is that these bikes are setup so lean from the factory it doesn't take much in the way of mods, ( esp. giving it more air ) and they start having driveablity issues.

I'd really love to do some mods to mine, but I really want to keep it as "start it up and ride it " as possible, and doing even some simple mods I'm afraid I'll start having similar fueling issues and I just don't want to deal with that.

I've got the racecar to be constantly tweaking ( and there is ALWAYS something ), which is enough. I think I'll leave the bike simple.
 
Eric have you had a dealer look at it? If you bike is bucking that doesn't sound like an issue a PC will fix. The bike should ride happly along at 3200 rpm.

I don’t know what the problem could be, but until you have the stock configuration baselined you don’t want to add any more variables to the equation.

Sent from my MB508 using Tapatalk
 
Thanks all. I do have a set of stock flies here. I cannot go back on the airbox without a purchase. I can put on the stock can and hook up the EXUP and could put on the AIS in working order... Do I want to? No.... but I may have to just to find out if this is a mod causing the problem. If I get it back to just the K&N filter and the cut airbox and it is will a problem, then it's start chasing electrical stuff. :(
 
You must log in or register to reply here.
Back
Top