05 flhti dies intermittently

[Markhamk]

Does anyone know what controls the fuel pump prime and the check engine light when you first turn the ignition??
This would be before cranking it over...
My bike dies right around the 12 mile mark (been as short as 2mi). Sometimes it will start right back up, sometimes its between 5 and 20 minutes, but it always starts back up and I ride home...
During this down time the fuel pump does not prime, and the engine light does not come on. I have all other electronics and it will crank without issue.
Read about temp sensor, replaced, no difference...
Also heard tip/turn module. Pulled it turned it all directions and both conditions do not fail.
Am getting ready to swap back to stock ecu from thundermax and with it unplugged the fuel pump still primes and the light still lights... super hard to diagnose something that is not happening for another 12 or so miles....

[Markhamk]

Brand new battery, cleaned connections on all fuses/relays/plugs to and from ecu.

[PoorUB]

The fuel pump will run a couple seconds when the key is first turned on. Then it shuts off and when the ECM sees the engine turning over it turns on and stays on as long as the engine is spinning.

[Markhamk]

Yes, but what controls them both at initial power to the ignition, before crank???
This is truly what I am looking to get answered...

[Coyote]

The ecm

[Markhamk]

Dont know what I was doing before,  I swear I had the thundermax unplugged....
I verified, unplugged again and sure as "Potty mouth", no engine light and no  pump prime...

[fbn ent]

Are you sure the system relay is good? My $.02.

[Markhamk]

Swapped the relay, same behavior

[IronButt70]

Had a similar issue on my 04 ultra. Turns out it was a connector under the fuel tank cover. 1 of the 3 male pins was slightly bent and not making good contact with the female side of the plug. Cleaned and straightened out the suspect pin, no more problem.

[Garry in AZ]

I had an intermittent engine dying issue on my 2007 Ultra. Bike would simply die, like it ran out of gas. Sometimes would restart, sometimes it wouldn't. The problem turned out to be a defective fuel petcock.

[fbn ent]

Just  try uncoupling the hose from the fuel tank (after running the pressure off) an recoupling. Easy thing to do and probably not the problem but....

[rigidthumper]

ECM activates the system relay for two seconds with key & run/stop switch both on. The ECM then removes the system relay enable until it sees a crank trigger signal (CKP) from the  crank position sensor. Once it sees a proper CKP, it enables the system relay, which passes power to the fuel pump, coil, and injectors. Ground side of the injectors and coil come from the ECM, which counts teeth and crank slow down to determine when to fire the injectors & coil. If the CKP stops ( loss of signal or engine rotation) the system relay enable is removed, pulling power from the coil/pump/injectors.

[fbn ent]

 

[No Cents]

 next time it does it and dies...try pushing upwards on the fuel line where it goes into the tank and see if it starts.