Bike Stalls after Idling

Billydj · #1 06-01-2008, 09:14 AM

This started at Bike Week in Myrtle Beach but thought it was caused by sitting in traffic for hours and the bike getting heated up but now I am not so sure as she did it the other day.

Bike runs completely fine and I'm not throwing codes.

At idle, I'm getting a littlesurge or cavitation...sometimes...didn't get it yesterday. In addition and I don't know if it happens when I'm experiencing idle surge or not (I'll check today),when I hit the gas to take off...bike stalls and it's like instantlyjust as you start to rev the motor. Fires right back up. Happened the other night after idling down my street, went to rev the motor a little...stalled...fired itright back up.

At Myrtle it happened once while making a left turn out of a suicide lane. Dropped a li'l doogy in myshorts as the cager lights were coming at me.

I just saw Tbones thread on a similar issue and it reminded me to post this and I didn't wanna hijack his thread. Any thoughts? On a 04A,does the fuel flange issueapply?

Thanks!
BillyD

Billydj · #2 06-01-2008, 04:03 PM

Diedagain today and the bike idle was erratic...going up/down so there seems to be a correlation. Any ideas fellers?

Thanks!
BillyD

NightStar · #3 06-01-2008, 11:06 PM

It sounds similar to the other thead so it may be a fuel flange. Are the rest of the electronics working ok?

Billydj · #4 06-02-2008, 06:59 AM

All other electronics seem to be ok and no spray outta the fuel flange.

Did some research on 1130cc.com and I'm leaning towards the tune beingthere's not enuff fuel in the 1500-2500 fuel range. I'll check other things as well but I think this is where I am gonna end up. Prior to the PCIII/pipes...everything was good. Always go back to your last change right? My last change was pipes/PCIII so I gotta check all electrical and then the tune which were theeffects of the mod.

Ride Safe....
BillyD

Hal64hd · #5 06-02-2008, 11:45 AM

Did you check your fuel pressure?
even thought the fuel flange is not a issue in 04 doesn't mean that the pump is not weak or on the way out. Especially if it has been run low a few times seeing how the fuel cools the pump

Billydj · #6 06-02-2008, 02:10 PM

I have not but I sure will now! Gotta travel a few days and then right back on this puppy. Stalling is just not safe although it only does itafter coming off of idle or hard play...still not safe at da lights as I await someone to jam their bumpy up me arse.

Thanks!
BillyD

Here's an awesome post from FatByRR on 1130cc regardingfuel appropriation on fuel injected engines...worth theread:

All fuel injected engines MUST shut off or nearly shut off fuel under decel. Just as fuel is "metered" for run conditions, different PULSE Widths are required under different DECEL LOADS. At the extreme decel loads FUEL IS SHUT OFF. When the engine sensors detect a "calibrated" either RPM limit or a new TPS input, fuel is re-enabled. This condition or MODE is decel fuel EXIT when the fuel and spark are matched so the operator doesn't know the engine has effectively "RE-STARTED". Think of this as a "CALIBRATED" bump start. If you turn off the ignition and turn it back on you get a bump when the engine re-starts. However, under DECEL fuel shut off, this is precisely what happens, but by adding the correct amount of fuel and matching spark this re-start can be masked so the operator never knows it happened !! And more importantly to this discussion, the RPM sag or FLARE can be calibrated.

Put in too much fuel and the RPM rises, and too LITTLE the RPM sags. If this sag occurs at an already LOW engine RPM the momemtum of the engine in a negitive direction cannot be overcome with added fuel and a STALL occurs when you de-clutch or pull the clutch in.

Under hard decel you go into this decel fuel shut off. Certian criteria must be met to reach this level of decel ( MAP. RPM, TPS, etc. ) without worrying about how you enter the mode, THE issue IS how you exit the mode.

Base software has many additional "MODES" that add-on or after-market devices may effect. You have added fuel for the base MAP readings but under some conditions the fuel added on a PERCENT basis is not enough. ie. 5% richer under "normal" decel is OK for decel "POP" or backfire, but it isn't enough for this DECEL fuel cut-off mode exit !!!
What happens is the system is calibrated ( based on again TPS, RPM, And MAP, AND ....HOW LONG THE FUEL HAS BEEN TURNED OFF!!) The fuel must compensate for the lack of fuel that has NOW evaporated OFF the port walls to have enough FUEL for a "re-start" when the fuel and spark are turned back on!! The lenght of time and the "VACUUM" level determines how much additional fuel or PULSE WIDTH the system will add for a "re-start". Too little and you get a stall when you pull in the clutch or a bump with the clutch out.

A little more detail for those interested:

When the engine is under hard DECEL just as it does under HARD Accel some extra fuel is added for the transition..."a transient fuel event". Under accel the fuel is added for manifold filling, and under decel, how long the fuel has been OFF evaporates fuel that has acumulated on both the port walls and valves. When an engine is running, some fuel is always present on the back of the valves and on the port walls that is not injested on a combustion event. Under steady state running, it is easily accounted for with tuning, as it is a constant amount. However, under transient fueling, this fuel film can be a greater or lesser amount, depending on the DELTA change in load and whether fuel is ON or OFF. When the fuel is turned back ON this fuel film on both the walls and valves accounts for some of the fuel "added" when it is re-initialized after being OFF. Then when the system needs to return to normall RUN fuel, some amount of extra fuel and SPARK are added to insure a smooth transition from "FUEL OFF to FUEL ON". If you pull in the clutch at the LOW end of the RPM re-enable fuel MODE, the amount of fuel added by the ECM + the percentage of added fuel from your add-on device (where the add-on fueler may be correct for NORMAL operation is not the proper amount for the FUEL cut off RE-ENABLE mode) the fueling to re-light the engine is not correct.

Your only choice is PUT up with the odd stall on a hard decel, OR put in enough extra fuel to prevent the stall and most likely add a little "POP" under decel. Not preaching but, that is one area where a "harley" tuning device like the race tuner that works in conjunction with the ECM software can be a little better than an add-on device. The ECM software would also add fuel for these "other" modes that are not comprehended with an add-on device.Or simply replace the ECM with a total after market device.

NightStar · #7 06-02-2008, 09:30 PM

So it gets more complicated

Billydj · #8 06-02-2008, 10:04 PM

Not really, just a good explanation of why those with pipes and a after-market tuner may need to add fuel in the 1500-2500 RPM range. That's what it boils down to.

Ride Safe...
BillyD

NightStar · #9 06-03-2008, 06:26 PM

That's making it a lot easier.