I am helping a buddy with his bike but I’m stumped, so before just throwing more money at it, I figured it wouldn’t hurt to ask help here. I apologize for the long explanation…

2008 Fatboy with the 96ci fuel injected and 56k miles. Bike is not running right, running rich, won’t idle long before cutting off.

It all started when he tried to plug a fuel pack into his ecm that had already been married to another bike. Something happened and blew a bunch of fuses and now having issues with running and idling even after disconnecting the fuel pack. (Bike ran perfect prior)

DTCs: P0113, P0118, P0123

I tried to start at the easiest solutions first, proper battery voltage and I checked all fuses and relays, made sure everything was plugged in and pulled the intake off to check throttle plate. Then made sure plugs were good (very black). Runs rich and black smoke when revving. Gap was correct and wires good. Matching temps while running at the exhaust tips and at exhaust port of each head. I scoped the cylinders and still plenty of crosshatching, no scores but some carbon. Compression is 180 and 175.

Then I moved to a fuel issue, pulled the console and the plate for the fuel pump. When turning to run, pump kicks on but fuel squirts out into the tank by the pressure regulator. Pulled the fuel pump and checked for broken plastic. Internal fuel lines are good, plastic housing is not broken or cracked. All seals looked good and pressure regulator looked ok. Replaced fuel filter and put it back together because I figured the fuel being temporarily squirted into the tank was just excess pressure from the initial draw on pump.

Pulled the tank off and started with checking the DTCs. Cleaned the IAC and made sure the plunger moved in and out with the run switch. Cleaned the IAT and the MAP sensor. Cleaned the TPS connection. Cleaned the throttle body and checked the Engine Temp sensor. Went through and cleaned all connections and added electrical grease. Still no change. Pulled the injectors and cleaned them. Used my power probe to activate the injector so I could clean. Still no change.

This led me to believe it was definitely electrical either sensors or ECM. Disconnected all questionable sensors and looked over harness and plugs. No broken wires, loose connections or broken plugs. Started doing continuity tests from sensor to ECM. Pulled up schematics and tested each end of the harness from ECM to Sensor. All wires had continuity. I did make sure all sensors that shared a signal wire, were disconnected so no load whatsoever. Then I started checking for the 5v references. Back-probed the ECM and checked each sensor plug individually. I have 5v at each sensor and proper pins at ECM. ( not looking at the schematic right now but I believe the TPS, IAT and ET all share the same 5v power wire from the ECM) Although I had 5v at the ECM pin that I thought should have been a ground. Figured it was either the ECM or the sensors. Replaced the sensors in question( TPS, IAT, and Engine Temp) and still no go. So the ECM is fried internally?

This is where I stopped and came here for some help. Thank you in advance I really appreciate it.

 

I wish I were an electrical guru, but I am not... so here is my 2 cents...

Something "bad" obviously happened when the FuelPak was plugged into his ECM. The fact that several fuses blew.... suggests to me there was an issue with the FuelPak, other than just not being married to the bike it was plugged into...

In any case, you've pretty much done everything I would have done. You did a nice systematic, detail oriented inspection/test on the bike.... You even tested the pins on the ECM and found one not doing what it should be doing...

IMHO.... Based on all you did, I would feel justified spending the money on a new ECM....

Good luck with the repair and let us know how it is resolved...