Engine stutter under load, idle seems fine

[waldawg]

My bike idles with no noticeable issues, but under operation, within about a 1/4 mile it starts this stuttering thing... almost like cutting in and out at a fast speed, or a low speed rev limiter.  If I open the throttle no difference, in order to make it stop I need to clutch, close the throttle and start over again.  Yesterday that worked for a few minutes and it repeated again, didn't think I would make it back to the garage. 

This occurrence started out as a freak occurrence in Pigeon Forge last week and began to increase as I returned home to Columbus OH.  Yesterday's occurrence was the worst so far, the only difference between yesterday and the other occurrences is I turned off the EITMS.  Also while in Pigeon Forge sitting idle in traffic, on hot 90 degree evening (EITMS ON) the security key light came on.  I don't have a security system...   I was clutching a lot in snail moving traffic, once I got moving it went out.  WTH?   

Here are the particulars... 2012 FLTRX, Harley SEPRT Tuner, 120 ST w/3500 +/- miles, SE Heavy Breather intake, Drago's Dragula 2's (2 into 1) exhaust.  Bike and motor still under warranty but dealer can't get me in till next Friday.  Any input would be great, thanks for reading.   

A check of the codes revealed P0131 and P0132.

[rbabos]

Sounds like lack of fuel flow. Fuel filter, or broken cansiter as well as the quick connect at bottom of tank not up far enough to open the valve fully. Either will restrict fuel flow, so it's not enough for higher rpms. I would also varify fuel pressure as being normal, as a first test.
Ron

[Ohio HD]

Both cylinders, or can you tell?

[waldawg]

Both cylinders, or can you tell?

Yes, it appears to be both cylinders.   

[waldawg]

Sounds like lack of fuel flow. Fuel filter, or broken cansiter as well as the quick connect at bottom of tank not up far enough to open the valve fully. Either will restrict fuel flow, so it's not enough for higher rpms. I would also varify fuel pressure as being normal, as a first test.
Ron

Agreed, it did appear to me to be fuel delivery also, but I have limited knowledge.  Fuel pressure test, got it.

[BUBBIE]

TEST........
While riding, or when it Misses... PRESS UP HARD on the Tank fitting. You should be able to FEEL it go IN further... Pushing it UP gives it FULL flow...
IF Restriction IS from Bad Fit or worn Balls...

Newer gas tube; rail to fitting is available from HD as a replacement...

signed....BUBBIE

[rbabos]

TEST........
While riding, or when it Misses... PRESS UP HARD on the Tank fitting. You should be able to FEEL it go IN further... Pushing it UP gives it FULL flow...
IF Restriction IS from Bad Fit or worn Balls...

Newer gas tube; rail to fitting is available from HD as a replacement...

signed....BUBBIE

Good idea. I'm still not sending you a check.
Ron

[Ohio HD]

If no codes are being thrown, I would say that Ron's post is the best first check.

[BUBBIE]

07 Sturgis Bound HTT Member last year: Stranded along side of road... Smart Phoning to HTT the Problem... HELP

Desperate:  No Fuel/not enough getting through on his ride...

Given the Test for him to try:

YEP it was the problem.

HD had the new Longer Nipple (?) replacement hose in Rapid.... He still wrecker/hauled his ride in BUT had the needed part Ready to change out....I'm sure he was Big Smiles for that... 

signed....BUBBIE

[waldawg]

TEST........
While riding, or when it Misses... PRESS UP HARD on the Tank fitting. You should be able to FEEL it go IN further... Pushing it UP gives it FULL flow...
IF Restriction IS from Bad Fit or worn Balls...

Newer gas tube; rail to fitting is available from HD as a replacement...

signed....BUBBIE

Ok, tried this today and can barely get the fitting to move at all, maybe a few millimeters... didn't stop the stutter. 

[Tynker]

Open the gas cap and listen closely, turn on the key and listen  for a hissing sound. If you hear it as pump is running,. you have a pin hole in the fuel line. This works(hear it better)  if you are low on gas.

[waldawg]

Ok, the dealer was able to recreate the "stutter" which he described as being similar to the "limp home mode".  He couldn't find anything wrong with any specific sensors, i.e., map, etc.  The spark plugs were white when they pulled them out and he never saw the red "security key" light come on.  I have the SE Heavy Breather on it, with 2into1 Drago 2's.  Is it possible the heavy breather is thinning the AFR out to much?  The original dyno tune (same breather) was around 12 AFR, isn't that a pretty rich mixture? 

The dealer tech said he called their tech assistance line and the only thing they can come up with is the bike has been broken in, (3500 +/- miles) and needs another dyno tune.  Is that true?  Do dyno tunes change when motor breaks in?  The stutter seems to be occurring around 2300- 2400 rpms.  I rode it home from the dealer and kept it around 2800 -3000, no stutter.  I did experience the red "key" light while stuck in "stop and go" traffic having to ride the friction zone.  I don't have an alarm system so I'm stumped by the security key light... is it overheating? 

[Downing883]

My 2015 883 did the same thing and they replaced the sensor in the exhaust. stopped doing it after that.


Hope that helps some or gives an idea

[rigidthumper]

If the bike was tuned with the current configuration, and some miles later issues with the tune arrived, then it's possible that tune drift is causing it- reflash the tune/reset the AFV and see if it's better.  Intake seals can cause this, but usually that shows up at idle. There should have been some historic code from the key lamp being illuminated.
12 AFR on a dyno sheet is only the WOT snapshot of a run- has nothing to do with the rest of the map/tune. Post up your map if you can, so we can see how it's set?

[waldawg]

If the bike was tuned with the current configuration, and some miles later issues with the tune arrived, then it's possible that tune drift is causing it- reflash the tune/reset the AFV and see if it's better.  Intake seals can cause this, but usually that shows up at idle. There should have been some historic code from the key lamp being illuminated.
12 AFR on a dyno sheet is only the WOT snapshot of a run- has nothing to do with the rest of the map/tune. Post up your map if you can, so we can see how it's set?

Thanks for the reply.  The tune was done with the current configuration.  I have no experience with the tuner to flash it, nor the required cables, but I'll fix that.  I do have codes that indicate the front o2 sensor is running lean, and a running rich code... 

Are the maps easy to get to when the tuner is plugged into the computer?  I've downloaded the Super Tuner and Caliberation Quick Sync from the Harley webpage. 

[Just Nick]

You stated there is a p0131 and p0132 code in the bike I would look into that and change the front 02 sensor the see what it is doing.

[KB]

If it was an evo I'd say the coil is bad. If you can borrow a coil off another bike try it. Sometimes simple tings are not so obvious when you have all that technology..