Surging, Sputtering at 4,000-5,000 RPM

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RossKean

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I assume that the problem was the same before and after the "flash"? 

Do the plugs and check the wires and caps while you are at it. 

Might still be worth getting the injectors cleaned and evaluated. 

Throttle position sensor is a possibility as discussed above.  You might check that the span is correct and that there are no obvious discontinuities via the diagnostic function.   That might or might not reveal a problem. 

 

BigOgre

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Just a note on the TPS, as said the DIAG screen may or may not reveal the dead spot.  I believe heat plays a part on the degradation of the sensor and checking this cold might not show on the screen.  A good tell is to get the bike nice and hot during a ride and then find the stumble point with your right wrist.  Note the RPMs there and you should be able to replicate the cough in any gear in that same range.

 

JerrySuhrstedt

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Update.  Installed new battery, new air filter, new plugs, synced the throttle body, and even pulled my fuel injectors and had them cleaned.  Did both a ohm meter and diagnostic mode test on the Throttle Position Sensor... it's solid as a rock.

Still have the dang stumble / sputtering / intermittent power at around 2000-3000 rpm!!

This is getting frustrating... any more ideas appreciated.

 

JerrySuhrstedt

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Just a note on the TPS, as said the DIAG screen may or may not reveal the dead spot.  I believe heat plays a part on the degradation of the sensor and checking this cold might not show on the screen.  A good tell is to get the bike nice and hot during a ride and then find the stumble point with your right wrist.  Note the RPMs there and you should be able to replicate the cough in any gear in that same range.
Ok, well I tested the bike cold.  I'll have to go out and run it hard then do the diagnostic mode thing.

 

Bounce

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Hmmm... guess I don't understand that.  My bike has the YSS automatic clutch... does that make a difference?  I'm just saying that if I continue holding my throttle in 2nd or 3rd gear at around 4000-5000 RPM and then continue to hold it there... the engine is not constant.  It's like something is plugged and allowing intermittent fuel to get through.  So it gives me intermittent power and the bike feels like it's jerking and not smooth.

With all that being said, your theory may be what I'm experiencing... I don't know.
FJR had low-load surging around 3500 until they changed the transmission and then (IIRC) all things happened at different RPMs than before but I would think that would shift the surging down instead of up. Commuting, stuck behind someone doing 35-40, and cruising along. It's more like the ECU can't pick a map and keeps flipping back an forth between 2 so it surges. The last post about it being there around 3000 RPM seems to hint at this though.

Maybe you're talking about something else.

 

JerrySuhrstedt

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FJR had low-load surging around 3500 until they changed the transmission and then (IIRC) all things happened at different RPMs than before but I would think that would shift the surging down instead of up. Commuting, stuck behind someone doing 35-40, and cruising along. It's more like the ECU can't pick a map and keeps flipping back an forth between 2 so it surges. The last post about it being there around 3000 RPM seems to hint at this though.

Maybe you're talking about something else.
I've had issues with surging on other bikes.  This isn't that type of thing... I'm experiencing sputtering.  A constant intermittent power like not enough spark or gas is getting to the motor.

 

infrared

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Jerry,

I'd be the first to say, I'm no expert on your issue. 

I would say, go for the easy stuff first.  Since the ECU handles all of that fuel stuff, I would try a good contact cleaner on the plug (and repeated re-connections of the plug, with cleaner).  Cleaning or replacing the TPS might be the remedy, but no digital readout of TPS operation is going to show glitches there, only the seriously bad defects.  Some multimeters have a bar-graph readout across the screen, besides the number readings, which can show "stutter."  Borrow a better multimeter, if you do not have that option on your multimeter.  The bar graph will show "stuttering" performance of the gadget being tested.

Since you have a 2006, an ECU re-flash by Ivan's Performance (Georgia) is probably worthwhile, even if that does not cure the problem outright.

Like I said, though, I'm no expert there.

 

dcarver

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  1. Fuel injectors and if you decide to remove them
  2. Spark Plug Caps
  3. Coil Replacement (due to spark plug cap / wire interface corrosion)
I have 4 Russ Collins cleaned and matched injectors on the shelf. If you want to use them, then send yours to RC Engineering, shipped back to me, they are yours. You pay shipping of course. At least you'll know if it's clogged injectors or not.

Given the low miles and low use.. 

  1. Bike not used with gas in tank for extended time = yukky gas = clogged injectors
  2. Air filter... have you looked? Mice-A-Nest-A-Romi?
  3. Not likely, IMHO, it's spark plug cap/wire with those few miles
  4. TPS - not likely unless you live in high RH areas like Florida (MTBF < low unless corroded)
  5. Battery sounds stupid... but... tight, corrosion free connections? Battery health check lately? Ground wire?
Unfortunately, Fortunately, I've accumulated and shared a lot of Gen 2 info here as I try to get KrZy8, 2006, to 250k with second engine.

Good luck,

dcarver

 

Bounce

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bad gas or the non-replaceable "sock" on the pump inside the tank (can't remove it but can "rinse" it) would be my first go-to.

 

Bounce

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infrared

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Sure sounds like a TPS.  You can test the original one.

This link is for auto engines but the process is the same.
Just a note on Digital Multimeters:  A straight digital reading of a TPS may or may not look okay.  The better DMMs have a bar-graph function above or below the digital reading, which can show any jitter or stutter in the readings, much better than just the digits can show.  Then, watching the bar-graph indication is more like watching the needle-swing of the classic old test meters.  Much better, for things like testing a TPS!

.

 

Bounce

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I used the Power Commander and used it's calibration process to watch how the TPS reacted to changes to the throttle. If it "stutters" in one area, you can figure there's wear on the contacts.

 

HotRodZilla

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Update.  Installed new battery, new air filter, new plugs, synced the throttle body, and even pulled my fuel injectors and had them cleaned.  Did both a ohm meter and diagnostic mode test on the Throttle Position Sensor... it's solid as a rock.

Still have the dang stumble / sputtering / intermittent power at around 2000-3000 rpm!!

This is getting frustrating... any more ideas appreciated.
Since you had the ECU flashed, I'm assuming you are NOT running a Power Commander?

 

SFZX

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I realize this is an old thread, but I have not been able to find anything on getting into diagnostic mode or using it. Is it available on the forum anywhere. I'm fighting a problem that could be just bad gas. Bike was running normal as it has for many years never an issue. All of a sudden after a trip of about 100+ miles I've developed a low rpm miss that seems to disappear with throttle application. Would like to determine if injectors are functioning as they should. Can the diagnostic mode accomplish that?
 

RossKean

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I realize this is an old thread, but I have not been able to find anything on getting into diagnostic mode or using it. Is it available on the forum anywhere. I'm fighting a problem that could be just bad gas. Bike was running normal as it has for many years never an issue. All of a sudden after a trip of about 100+ miles I've developed a low rpm miss that seems to disappear with throttle application. Would like to determine if injectors are functioning as they should. Can the diagnostic mode accomplish that?
What year is the bike? Diagnostic mode can be used to check some stuff but may not be helpful to test injectors for anything other than basic function. Check for stored fault codes...
 

SFZX

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What year is the bike? Diagnostic mode can be used to check some stuff but may not be helpful to test injectors for anything other than basic function. Check for stored fault codes...
the bike is a 2008. It's been perfect all these years has 30,600 miles on it and have never done anything but change the oil and filters and ride it. Just need to figure out the present missing issue. I've removed the tank and am going to drain it today and try fresh gas, this started so suddenly I felt I might have gotten bad gas. Tried a bottle of Heet with injector cleaner in it, its a little better but the problem comes right back. Checked the plugs all look normal, #1 slightly darker in color than the other three. Was also going to look at resistance numbers on coil to plug wires. I will have a look at the TPS diagnostic as well, thanks for the quick responses guys!
 
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SFZX

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OK so here is what I have now! Got diagnostic open no codes thrown or in memory. Tested coil for 1&4 got the spark plug to fire grounded on head bolts for 1 & 4. Exact same for 2&3. So plugs and wires in good shape. Tested all four injectors and I hear them fire five times when flipping ON-OFF switch with engine check light. I assume basic function good ? is are they spraying properly.
Now the only thing I saw was TPS when full throttle rolled on is 101 should be 97-100?????
Is that one extra point causing this? I would doubt it?
 

BigOgre

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I doubt it also. Still sticking by what I wrote earlier:
Just a note on the TPS, as said the DIAG screen may or may not reveal the dead spot. I believe heat plays a part on the degradation of the sensor and checking this cold might not show on the screen. A good tell is to get the bike nice and hot during a ride and then find the stumble point with your right wrist. Note the RPMs there and you should be able to replicate the cough in any gear in that same range.
In your case you said it came on after a 100 mile ride and the miss was in the low RPM range which to me points to the TPS, especially after what you already checked for. The TPS will wear with every turn of the throttle and if you think about it the low RPM range gets the most use as you always have to go through that area no matter how you ride. (Sorta like the old data how you're most likely to get into an accident if you're closer to home. Well, yeah. Every time you leave home you have to travel the same roads over and over so odds are . . . .) Anyway, I'm not usually eager to throw parts or money at a problem but if that's the original TPS, for about a 100 bucks or so it might not be worth all the difficulty of trying to diagnose a bad one. Chances are it'll degrade some (or more) with time and, like several others have discovered, it might surprise you and solve the problem.
 

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