Odd electrical problem, stumped and need advice

[speedfoos]

OK, so here goes.

Symptoms: Bike intermittently dies off throttle if given time, and is excessively lean when off throttle and decelerating.

Description/timeline: Yesterday I rode the bike to work (30-mile, one way) and it behaved like it normally does, no issues at all. Two hours after I get to work, I have to go to another building on post, so I hop on the bike (starts right up), pull out of the parking lot, go to the stop sign (50 feet away) and it dies on me while I'm at the stop sign. Starts right back up but continues to die if given the opportunity (clutched pulled in and off throttle), but runs fine when given any amount of throttle. I ride the 4 miles to the other building, take care of my business and get back on the bike to go back to my office. Bike starts up fine and runs perfectly normal all the way back to the office and later in the day when I go home, I have zero issues either.

Odd.

This morning I grab the bike and head to work and get about halfway there when I hear the bike pop excessively on an off-throttle decel. Hmm... I pull the clutch in and it dies again just like yesterday. Again it continues to ride fine under throttle but is too lean on off-throttle decel. Thinking about this, I reach down and shut the bike off via the key, count to three, turn it back to IGN and release the clutch to run start it as I was still going about 40mph at that point. Bike starts back up and exhibits none of the previous symptoms on the rest of the way in to work.

Really odd.

Even when misbehaving during off-throttle, it runs perfectly under throttle with no loss of power or detonation that I can hear or feel.

Bike specs: 2004 FXDLi (fuel-injected) with 22,000 miles on the odometer

Bike mods: intake, exhaust, Stage 1 flash. Nothing has been changed on the bike in the past 12,000 miles.

What I've checked: Bike has not thrown any codes. Has a full tank of good, fresh 93 octane gas as I filled up on the way home yesterday. I pulled the intake manifold off last night and checked everything up to the throttle plate and all was fine. I just pulled the ECU fuse for a few minutes to let things reset and have not ridden it yet since resetting the ECU.

What I think: Feels like an electrical problem because the problem went away both times after shutting the bike off and starting it back up again. Bad gas would make the bike consistently run poor, faulty/clogged fuel injector would also continue to run poorly after a shutdown cycle. Basically anything mechanical would continue to misbehave after I cycled the power on the bike like I did this morning.

I'm stumped and will welcome any suggestions.

[TXCHOP]

Pinhole in fuel line or broken injector wire. My 2 guess..If it get worse the lower the fuel level look in the tank. If its erratic, try wiggleing the injector wires when it occurs.

[brownfoxx1]

with a quick scan of my elec. diagnostic manual for the '09 tri-glide. problem poor ferformance

1. manafold leak
2. MAP sensor plugged or not operateing properly.3
3.crud in gas tank
4.spark plugs
5. low fuel pressure
6. clogged fuel filter
still looking

[speedfoos]

Originally Posted by TXCHOP

Pinhole in fuel line or broken injector wire. My 2 guess..If it get worse the lower the fuel level look in the tank. If its erratic, try wiggleing the injector wires when it occurs.

Problems seems independent of fuel level. It did it yesterday on an 1/8 of a tank and today on a full tank. Kind of hard to wiggle the injector wires when its running (a little hot down there), but I probably will pull off the throttle body tonight and see what's going on.

Originally Posted by brownfoxx1

with a quick scan of my elec. diagnostic manual for the '09 tri-glide. problem poor ferformance

1. manafold leak
2. MAP sensor plugged or not operateing properly.3
3.crud in gas tank
4.spark plugs
5. low fuel pressure
6. clogged fuel filter
still looking

1. Checked and its not leaking.
2. Have not checked but it should throw a code I'd think. Will look into that as it kind of makes sense because if the ECU is getting a faulty/non-existant signal from the MAP sensor at 0% throttle position, it won't know how much fuel to throw. What doesn't make sense is why the problem goes away after an ignition/power cycle.
3. Tank is relatively new and clean.
4. Spark plugs are new with less than 150 miles on them.
5. Possibly, but again why is it not consistent and disappears after the power cycle.
6. Same as previous.


I'll continue to check this thread throughout the day. Right now, my plans are to pulled the throttle body and inspect everything and also pull the fuel pump assembly and check all of that. The only problem with those items is if they were faulty, they would be faulty all of the time and not disappear after I power cycle the bike. Unless the power cycle is a red herring, which I doubt because it 'worked' the two times this has happened.

[brownfoxx1]

in ser. manual. starts,but runs irr,or misses. spark plugs in poos condition;plug cables shorting or leaking;plug gap too close or too wide;falty ign coil,ECM,semsor;battery nearly discharged;damaged wire or loose connection at battery terminal,coil or ecm connector;injtermittent shrtcircuit due to damaged wire insulation;watyr or dirt in fuel;fuel vent system plugged;air leak at manafold or air cleaner;loose or dirty ECM connector falty sensors TMAP, CKP,02 ; INCORRECT VALVE TIMMING;WEAK OR DAMAGED VALVE SPRINGS;DAMAGED INTAKE OR EX. VALVE;PARTIALLY PLUGGED FUEL INFECTORS.
later on a good fuel inj. cleaner is bg44k. lb

[DaGriz]

Sounds like a manifold leak or fuel problem as it does not do it on acceleration.

[speedfoos]

Right so I've just about checked everything. Bike was fine on the way home, didn't misbehave at all. I pulled the intake manifold and throttle body off. Nothing wrong with them that I could see but I didn't expect anything because I don't think that's the problem. Just to be safe I cleaned my injectors in my ultrasonic cleaner, scrubbed everything else up nicely and put it back together.

I checked all of the grounds and freshened up the connections on them to ensure there was good contact. I pulled all the fuses and burnished the corrosion off the blades, I double checked every connection on or near the ECU. My plug wires are newish, plugs are brand new and coil physically appears fine.

The only thing I did not do was inspect the fuel pump because I'm tired of gas fumes right now from taking the fuel tank on and off twice, plus I don't think it has anything to do with the pump assembly.

I also dumped half a can of Sea Foam in the gas tank.

So I don't know. Bike started up after I put it all back together and idled perfectly. I have no idea what the problem could be because its not consistent and there is no physical evidence of anything being wrong. Guess I'll wait to see if it happens again and take it from there.

[DaGriz]

Could be the bike is jealous and pissed at you for working on the rice burner and decided to mess with you to get even and get some attention!

[wkohn]

Sounds to me like you have a wire that has a small cut and is shorting out.


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[speedfoos]

Originally Posted by DaGriz

Could be the bike is jealous and pissed at you for working on the rice burner and decided to mess with you to get even and get some attention!

Yeah yeah yeah.

Originally Posted by wkohn

Sounds to me like you have a wire that has a small cut and is shorting out.

While I have not gone and checked for continuity along every single circuit, I doubt this is the case as I visually checked every bit of wire that I could get to without pulling the main harness out of the frame. If there is wire in a place that I could not get to, its also in a place where it could not be cut.

In doing some more research I have a couple more things to check before throwing in the towel for a moment. Two things can cause the bike to die intermittently at idle and those are the IACV and speed sensor. I removed, looked over and wiped down the IACV last night but didn't do an in-depth clean on it so I will do that tonight. Since it controls the idle of the bike, it's possible that it is gummed up. I doubt its this because of the whole ignition cycle thing, but who knows.

Also the magnetic speed sensor - which sends a signal to the ECU that is paired with readings from the MAP sensor to determine the proper amount of fuel to dump at any given moment in time - can collect a lot of metal shavings that in turn can cause a faulty/screwy signal to get sent to the ECU. This will also cause the bike to cut out.

I'll check those two things tonight and hopefully find something, if not I'll keep chasing red herrings.

[DaGriz]

Send Mark an email and/or Facebook message and he will talk to his Head Tech.

[speedfoos]

That's all right, I'll wait until the problem crops up again.

Cleaned the IACV tonight, really wasn't dirty. Pulled and wiped off the speed sensor (had no metal on it), put it back together and started it up and it threw some codes because I forgot to plug the IACV, rear injector (all the way) and fuel gauge back in.

Plugged everything back in, started it up and it idled just fine, no codes, stable "potato-potato-potato" idle, perfect. Threw on a jacket, some gloves and my helmet and then threw my leg over the seat and took it for a ride. Ran like a scalded dog as usual for the rip up and down the street.

I'm at a loss as to the cause but I've checked and "fixed" a bunch of things so I will just ride it at this point until/if the problem comes back.

The key thing to remember about the strangeness of this problem is that it went away both times after the bike was turned off at the key.

[RustyG]

EFI bikes will act erratically if you open the throttle during the start process. Maybe the throttle cables are binding or you are opening the throttle a bit when starting?
Doing so will give the EFI a false TPS reading.

[speedfoos]

Originally Posted by RustyG

EFI bikes will act erratically if you open the throttle during the start process. Maybe the throttle cables are binding or you are opening the throttle a bit when starting?
Doing so will give the EFI a false TPS reading.

Nope, TPS's simply don't work like that. They send a set voltage at every range in the throttle plate position and that only gets screwed up if the owner somehow moves/clocks the TPS out of its factory position without the ability to tell the ECU what the values now mean.

Throttle cables aren't binding, but good suggestion as I checked and lubed them as much as I could.

The only thing I can think of is that something was messed up in the idle portion of the fuel table in the ECU causing it to cut fuel when it saw the throttle plate shut. If it was the MAP, TPS, or speed sensor it would have thrown a code, but it didn't. Since there were no codes, nor any consistent physical evidence of anything, the only thing I think it could be/have been is in the ECU with the fuel/spark tables. I'm hoping resetting the ECU and forcing it back to a fresh stock config fixed the problem. I'll be on the bike as my commuter for the next two days so we'll see if the problem crops back up.

[claydbal]

Speedfoos, first let me applaud your logic. You are hired!!!
Lots of folks dont have your ability but talk chit about their custom shops. You are a breath of fresh air!!!.

Now,.......... its a dyna custom right? Dash switch? 04?. Ok. The switchh itsrlf will fugg up and ya get a voltage drop even though it all seems fine.