I have a 09 Fatbob,it has the screaming eagle heavy breather intake and the factory download. The pipes are standard. The bike runs well and I am pleased with its performance, but under hard acceleration it sounds like it pings.This is probably at 4500 rpm, never at lower engine speeds.
I run 92 or 93 octane fuel although some has 10% ethanol.
Any thoughts out there? What can I do to prevent it? other than never cranking on it!!! I figure maybe a fuel management system, factory or aftermarket? which one is "best" Thanks for any input
You have kind of the reverse of your typical pre-ignition noise. In most cases you get the spark knocking most pronounced at the lower rpms and under load. If what you're hearing is actually spark knock then your timing is probably off with too much "all in" advance. This would automatically mean your advance curve must be lagging. Not very likely at all but remotely possible...I guess.
It's just odd that you're getting this noise only at the upper end of the rpm spread. It makes me think that you might be hearing some other noise, like maybe loose or poorly postioned heat shields or lifter noise, and you're thinking it's spark knock. I'd have the dealer, assuming it's still on the warranty, check the timing advance, advance curve, and VOES (if your bike has one). Once you rule those ignition things out (if that's the case) go looking for another source of the noise like something mechanically tapping on something else.
A fuel modifier will help your engine run richer and cooler but I'm not so sure you're hearing pinging. A sharp mechanic with a lot of experience and a good ear would go a long way to getting you on the right track with this noise.
I'm surprised you can hear any pinging at 4500 R's,, whenever I've gotten detonation at Hi-R's it was felt more than heard,, kinda like a tiny miss & it was A/F based..
Anyway, stay with the high octane at your pump cuz it will help to ward off detonation cuz your motor is Lean from the factory..
I believe ALL gas is now comtaminated with Ethanol so there's nothing you can do about that..
Try this----
Take it out and Jam-it,, make it ping..
At that precise moment dis-engage the clutch and switch-off at the same Instant..
Do not down-shift or release clutch or Anything,, simply coast to the road-side..
Gloves on, wrench out,, pull the plugs..
If there are teeensy black or gray dots on the porcelain that is a sign of detonation/pinging..
If the porcelain is very white also the A/F mix is very lean and possibly the cause..
At this point A/F is my first guess..
I bet a fuel management will help tons..
TommyGlide raves about his, perhaps he'll tell you about it..
A buddy of mine just got a Cobra and loves it..
What Mil said about tooo much advance AND the advance rate "lagging" makse No sense..
A lagging or slow rate of advance would Retard the timing and dis-courage detonation..
__________________ "Fill your hands you son of a bitch"
Rooster Cogburn
I don't know enough about EFI systems to flatly rule out the "lagging advance curve" theory. Which I interpreted as ignition not reaching full advance (possibley too far) until 4500 rpm in this case. But, since full advance should be reached WAY sooner than that,I gotta go with the too lean thing...noting that it's not at all uncommon for would be tuners to get AFR wrong in ANY rpm range...carbed or injected.
Best recommendation IMO is like frisco sez...let the spark plugs tell you what's going on in there OR have the bike dyno-tuned by a REPUTIBLE guy...noting that even I know that just tossing a "generic" download on an EFI system is like some carb tuning clown tossing jets in a carb based on what would seem to be called for OR what he was told to do...etc. That and there's always the possibility some "crud" in the system could be restricting fuel flow at higher rpms that would'nt effect anything at lower rpms.
Meanwhile,though...I would'nt discount the idea that maybe the "pinging" heard is from something totally unrelated, either. Because (example) not long ago one of our members discovered (after a lot of head scratching here) that his suspected "spark knock" was just his new helmet visor rattling in the wind at certain speeds...and NOTHING surprises me anymore.
Well...not much anyhow.
__________________ "If at first you don't succeed, try again...then swear"
Mark Twain
All good advice I've read so far. Hear is another thought. I had the same situation with my 07 Fatboy. It ran great, but I heard what sounded like pinging, or rattling under hard acceleration. My bike has an aftermarket exhaust and air cleaner along with a dyno tuned Power Commander (fuel management) So I knew it wasn't pinging. What I discovered is that the stock compensator spring pack was too weak to handle the load at full throttle acceleration. What happens is that it bottoms out and hits the rotor under hard acceleration. I replaced it with a Screaming Eagle compensator, and the noise went away. Plus the bike starts smoother and really hauls when you crack it open. Just a thought. The SE Compensator kit is in the P & A catalog and sells for $249 (at least when I bought it) Some dealers say it's just for drag racing blah blah blah. Don't believe it. It is what sould have come from the factory in my opinion.
The fact that "pinging" is heard only at 4500 rpm and above makes me think that if it is spark knock then the advance is only too much at the higher rpm. This would imply that the timing is not too far advanced in the lower rpm ranges. The only explanation for that would be that the advance curve was somehow off and "lagging". Not very likely as I said. It might be remotely possible if the download Mid got from the dealer was wacko somehow. Not very likely at all however.
The symptoms Mid gave where the noise is only heard at 4500 rpm and above are contrary to my experience of spark knock where the "pinging" is usually more pronounced at the lower rpm and almost never apparent only at the higher rpm. I'm not saying that it isn't spark knock. I'm just saying I'd check out the all in timing, advance curve, and possibly VOES to eliminate them as culprits. If they are OK then look elsewhere for the cause. Maybe something mechanically tapping on something else.
I'm all for fuel modifiers to make the engine run better and cooler and no matter what the cause is for this noise I would add a fuel modifier if it were my bike.
I believe the Delphi ecm has an anti spark knock mechanism that works quite well so just suppose that can be ruled out. I don't think the Fatbob has a tach but a rider would know if he's closer to 4500 than 2500, so a lean afr? We know they are too lean to begin with, that's a gimme, WOT is supposed to be in open loop with a richer afr, but is it rich enough? We all have heard complaints about various fuel modifiers but the Cobra seems to be good, so says Scruffy Pup and Friscso's buddy and way cheaper than a Thundermax.
If it turns out to be your visor rattling ya better keep that to your lonesome, hehe.
If your running a HD download most likely your pinging, it's still to lean, if it were mine I'd get me a new TTS tuner and have it installed and dynoed tuned by a certified shop.
I believe the Delphi ecm has an anti spark knock mechanism that works quite well so just suppose that can be ruled out. I don't think the Fatbob has a tach but a rider would know if he's closer to 4500 than 2500, so a lean afr? We know they are too lean to begin with, that's a gimme, WOT is supposed to be in open loop with a richer afr, but is it rich enough? We all have heard complaints about various fuel modifiers but the Cobra seems to be good, so says Scruffy Pup and Friscso's buddy and way cheaper than a Thundermax.
If it turns out to be your visor rattling ya better keep that to your lonesome, hehe.
Tommy, thanks for mentioning this. What you say about the Delphi anti spark knock being built into the ECM made me wonder if that function is working properly. I'm pretty well up to speed on FI in a general way but my only hands on experience with FI is from a '73 Porsche 911E that I had. All its functions were done mechanically and not electronically so my knowledge about the electronic systems is limited. Still the fact that there is an anti spark knock feature makes me think that it is getting its info from a sensor somewhere. Might it be possible that that sensor is a little wacko? Or maybe the download is wacked out. If the engine didn't do this before the download that would tell you something also.
Like I said before, the symptoms of only experiencing the noise above only 4500 is contrary to my experience of spark knock in general so I'm thinking the cause here is something beyond the ordinary and usual cause which is overheating from too lean a fuel/air mix on the late model bikes.
It is possible that an aftermarket fuel modifier would solve everything but personally I'd want to solve this mystery first before I added the new mod.
Nice car Mil, and good point about the anti spark knock sensor being whacky and I can't find reference to it in my service manual. I THINK the stage 1 download alters the timing a little bit as well so that also could have gone wrong, maybe in the softwear or some such.
And yes, best to solve the mystery first, it could haunt a rider otherwise when it would be most inopportune.
Pinging on acceleration 
anyhow. 
Linear Mode
