Back at it again... Bike warm start issue.

[rmanjarrnm]

Hello everyone again, though i had solved the issue already, but long story short. I was recently riding my bike around town just running errands. Bike is running wonderfully with no issues. After stopping at a local parts store for a tool, i went out to restart my bike and when turning the ignition, the starter and engine was just turning over as normal but not starting.... i try a few more times but no luck. one thing i noticed is that the fuel pump has a different tone compared to its cold start up. it sounds as if its struggling then the whine slowly gets louder to it normal tone til it stops. I hooked it up to my car battery and it fired right up. Because of this i was under the impression that my battery seemed to be having issues, so i put my volt meter to the battery and it was running strong in every instance (hot/cold etc all above standards during sitting starting and running) Either way i figured i didn't know the last time the battery was replaced so i figured it would be good to replace it anyways. so after replacing the battery it was running into the same exact issue. When engine is cold it starts right up in less then one rotation, fuel pump priming tone is consistent and bike runs wonderfully. After driving even for more then 5-10 mins when the bike is warmed if i shut it off and let it sit for 5 mins or more the fuel pump has a very weak sound that progressively sounds normal and the engine will have to spin for 20 secs before the bike starts if it even starts at all. When the bike is running its has no issues at all in both instances. I have since replaced the plugs and wires also since i didn't know the last time they were replaced by the previous owner. Im under the impression that the engine heat is causing a the pump to be weak, maybe some sort of vapor lock issue on the lines that the pump cant push through? No codes on the bike, only thing im confused about is how the bike runs fine when running if it was the pump. Help please! Wanted some input before i buy the rebuild kit.

 

[njloco]

You don't mention which model or year that it is, what mods have been done to it, which battery you installed and the amperage of it, it would be wonderful to know these things.
Did you check all of the grounds if not clean them all off and apply an anti-corrossive.

 

[rmanjarrnm]

That might help, So its a 2005 xb9sx. does have a dnd exhaust with race only ecu. Full wire clean-up with new grounds and heat wrap on all wires handle bar swap for a more aggressive 1120 set with fab work to fit original cluster. After doing a ground test to the frame the grounds seem fine. The Battery is running at 12.5v while starter is turning. Random question would the grounds be affected by the heat alone? Wouldn't it cause an issue on a cold or semi cold start as well? I just installed A Big Crank CX-14 i believe it was from battery mart. Had it load tested before i installed on the bike at a local parts store since I've never ordered a battery online. I'm thinking its either a weak pump that is losing power when heat soaking or a back coil that is heat soaking and causing a weak spark. The one thing that I have noticed is just by the priming pump sound alone I can tell if it will instantly start or not.

 

[Endopotential]

I have an '09 XB9SX and had the opposite problems - the bike had a really hard time catching on a cold engine. It would turn over, but I would have to hit the starter button several times before it would run. With the engine warm, it would ride fine, no bogging; would also restart up just fine. This led me to think it wasn't the fuel pump.

Finally gave in. Turns out the the flex hose within the setup had a pinhole in it and prevented full fuel pressure at startup, I'm guessing.

So unless you have a way of measuring fuel pressure, may just have to bite the bullet and rebuild the pump which is notoriously prone to failure on our bikes.

FYI you can take out the fuel pump with lifting the rear up, unbolting the shock but not necessary to removed the back wheel.

 

[rmanjarrnm]

Yeah last night i pulled the air box off and when warm i sprayed a little bit of starter fluid in the motor and it kicked with the starter fluid instantly then died when it used it all up, so def has a spark... I then tested the voltage at the connector for the pump and it stays consistent when hot or cold so yup im biting the bullet. (edited the spark part because i think worded it in a way that makes it seem like i think its a spark issue.)

 

[njloco]

How about checking out or changing out the pump relay ?

 

[34nineteen]

If it sounds like a duck and acts like a duck, it’s probably a duck.

 

[kz6fittycent]

You can get them from a Harley dealership but I got them from Amazon: https://www.amazon.com/gp/product/B0012TT5BI/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Here's the OEM part #: MC-RLY5

 

[njloco]

You can pretty much also get them from any auto parts store, just make sure the end terminals match up.

Also, if you sprayed starter fluid into it and it started but stopped running after it used up the starter fluid, then it's a fuel issue not a as you said a spark issue.

 

[34nineteen]

one thing i noticed is that the fuel pump has a different tone compared to its cold start up. it sounds as if its struggling then the whine slowly gets louder to it normal tone til it stops.

the fuel pump has a very weak sound that progressively sounds normal and the engine will have to spin for 20 secs before the bike starts if it even starts at all.

Im under the impression that the engine heat is causing a the pump to be weak.

I'm thinking its either a weak pump that is losing power

I'll say it again... If it sounds like a duck and acts like a duck, it’s probably a duck.

Rather than hypothesize every reason that it cant be the pump, why not put that energy into verifying that it isnt (or is) the pump. It could be vapor lock, or the aggressive handlebars you installed, maybe the custom fab work? Are you sure the bike isnt going into skip spark/parade mode? Are you running AMSOIL? Have you ruled out solar flares and the possibility of EMP? Have there been sightings of UFOs in the area?

 

[Endopotential]

Pretty sure only the 2006+ ECU models got EMP nuclear shielding.

UFO protection was only available on the Race ECU modules.

I also hear that alien ducks have also learned to mimic terrestrial water fowl in their verbalizations, so you can't trust anything out there... :angel:

 

[34nineteen]

Pretty sure only the 2006+ ECU models got EMP nuclear shielding.

UFO protection was only available on the Race ECU modules.

I also hear that alien ducks have also learned to mimic terrestrial water fowl in their verbalizations... :angel:

Little known fact= it was available in some late 2005 ECU's, but it was called "transient electromagnetic disturbance protection". Earlier ECU's could be reflashed to have this feature, but this was rarely done.

 

[kz6fittycent]

Lemme know when there's protection against direct plasma discharge due to CME impacting upper ionosphere with ground to sky discharge as a result of inductive coupling. That's worth waiting for.

 

[Outlaw]

Skynet is behind all of those potential problems

 

[Endopotential]

Little known fact= it was available in some late 2005 ECU's, but it was called "transient electromagnetic disturbance protection".

Think it was actually "Transient Electromagnetic Radio Disturbance". TERD protection, just like your avatar!

And yes, a massive CME aurora borealis over California would be pretty cool to see. For now we'll just have to settle for forest fires and blackouts.

Oh the poor newbie is wondering WTF, how did we derail his thread on a fuel pump.
This is so much more entertaining!!!

 

[34nineteen]

Think it was actually "Transient Electromagnetic Radio Disturbance". TERD protection, just like your avatar!

And yes, a massive CME aurora borealis over California would be pretty cool to see. For now we'll just have to settle for forest fires and blackouts.

Oh the poor newbie is wondering WTF, how did we derail his thread on a fuel pump.
This is so much more entertaining!!!

Don't be talking trash about Domo! :black_eyed:

Actually, I think I put this thread on point and called out the obvious, before I (ok, we) took it off the rails. LOL!

 

[rmanjarrnm]

Haha, i turn away for one second and come back to this. Def had a few laughs reading through all the replies. Just ordered a new rebuild kit from a man some call john... I'll keep you guys updated.

 

[njloco]

Yeah, we went off the deep end on this one but let us know how it works out.

 

[rmanjarrnm]

Yeah, we went off the deep end on this one but let us know how it works out.

OK so i finally got the pump out, and it looks like it has already been built previously. everything is clean shiny and new but it looks alot different then the pumps ive been seeing on videos and websites, this one has the regulator on top of the pump vs the filter? Maybe this is a stock pump and just has been kept extremely clean?..... so a little frustrated i began to check all the connections and wires and when wiggling the regulator i realized where the regulator connects to the pump, it is extremely loose feeling before removing any brackets or anything with the slightest bit of pressure it slides up and down. included pics. Is this suppose to do that?

 

[Sdrxb12s]

That's what my factory one looked like