Ready to rip my hair out 🤬
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,863
Likes: 7,981
From: poway
The miss-fire sensing is done by circuitry inside the ECU. Here is a example as to how the sensing is done..
https://bmwmotorcycletech.info/ioniz...-susbystem.pdf
The reason as to why you don't see it when reving the bike is that the ECU needs to sense a load on the motor before performing ion sense through the map sensor. You could try to whack the throttle hard and it might occur. Simple blipping don't create enough load for the ECU to sense.
You could try new plugs but I suspect that they won't help. Since the condition always seems to appear on both cylinders, the only common connection between the 2 is the ion sense line going to the ECU.. I guess it could be shorted to ground somewhere... Check for that..
Maybe @Steve Cole would know as he's the delphi expert.
2nd Gear
Joined: Aug 2023
Posts: 6
Likes: 0
From: NJ
P1353
Has anyone solved this yet? I am having the same problem.
Replaced with OEM:
injectors
Intake manifold gaskets
Coil
crank sensor
Internal tank fuel lines
MAP
Plugs
Plug wires
All System relays
Fuel pressure holds at about 60psi
Front cylinder compression 170
Rear cylinder compression 170
Charging system 14.3 at 2k rpm
checked each individual wire for continuity from ecm to components
Replaced with OEM:
injectors
Intake manifold gaskets
Coil
crank sensor
Internal tank fuel lines
MAP
Plugs
Plug wires
All System relays
Fuel pressure holds at about 60psi
Front cylinder compression 170
Rear cylinder compression 170
Charging system 14.3 at 2k rpm
checked each individual wire for continuity from ecm to components
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,863
Likes: 7,981
From: poway
Has anyone solved this yet? I am having the same problem.
Replaced with OEM:
injectors
Intake manifold gaskets
Coil
crank sensor
Internal tank fuel lines
MAP
Plugs
Plug wires
All System relays
Fuel pressure holds at about 60psi
Front cylinder compression 170
Rear cylinder compression 170
Charging system 14.3 at 2k rpm
checked each individual wire for continuity from ecm to components
Replaced with OEM:
injectors
Intake manifold gaskets
Coil
crank sensor
Internal tank fuel lines
MAP
Plugs
Plug wires
All System relays
Fuel pressure holds at about 60psi
Front cylinder compression 170
Rear cylinder compression 170
Charging system 14.3 at 2k rpm
checked each individual wire for continuity from ecm to components
You have the exact same bike, same miles, same add ons and have the exact same symptoms?
Last edited by Max Headflow; Aug 16, 2023 at 11:40 AM. Reason: cleanup
HDF Community Team
Joined: Nov 2012
Posts: 6,186
Likes: 2,412
From: USA
I would suggest you start your own thread, for clarity and interest.
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HDF Community Team
Joined: May 2022
Posts: 506
Likes: 241
From: CA
Check all wiring and connectors between the coils and the ECU. If you actually had regular and persistent misfiring in both cylinders you'd know about it without any CEL! It's also unlikely both sensors would fail the same way at the same time, so my money is on a loose connector or pins, and the ECU doesn't actually get any sensor feedback. Second possibility would be that the aftermarket coils had a feedback signal that damaged the ECU, both cylinders exactly the same way.