ebatr24
Senior Member
- Joined
- Jan 20, 2018
- Threads
- 10
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- 1,008
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- Location
- Oregon
- Vehicle(s)
- 2017 Civic Type R, 2018 Civic Si Coupe

- Thread starter
- #1
At my wits end with my FK8 today. Although I am pretty mechanically inclined and can do a lot of my own work, electrical issues is kind of where I draw the line for my abilities. I've been having some trouble for the past couple months, looking for some help or suggestions.
Recollection of the problem: This started after a CMC swap was done by a local shop. (I was lazy and didn't want to do it myself) What it would initially do is jerk strongly kind of like an old manual car when you get on and off the throttle on take off, like when you're first learning to drive manual. I thought maybe the CMC was improperly adjusted as it had little to no play. I adjusted it and this problem went away or so I thought. Around this time I had also asked my tuner (DRob) for a revision with a little more mid range torque, which he provided. I had flashed the tune and later discovered that the car would stumble when given around 30-40% throttle around 4 or 5k rpms. It would basically cut throttle for a moment, you can let out of the throttle and put it back usually it feels back to normal. Went back to known good revision, problem still occurred so ruled out it being tune related. Lately it has started to do even more weird stuff, now when it has throttle cut out the audio system will also freak out and play sound only through the front speakers. The other day on the freeway I went to do a pull, and the car cut throttle more aggressively like traction control kicking in, the audio system also freaked out two or three times, and the brake light on the dash kept blinking. I limped it to my destination and as I was reversing the screen kept shutting off and on. This morning, I was driving the car went to roll my window down, and both the driver and passenger were lowering as I was pressing just the driver side button. The hazards also blinked twice as I was starting the car too. Couple other observations I've noticed is the car would only do this at part throttle before, only recently has it done it at full throttle. There is no knock or misfire happening in my datalogs so it doesn't seem mechanical at all.
I use to think this was something mechanical like misfires, but I am leaning towards maybe being a faulty BCM. I have no way of proving that though and I'm afraid to take it to a dealer only to pay a lot of diagnostic fees and they aren't able to reproduce the problem as the car acts and drives normal most of the time. Any ideas or insights would be appreciated.
Recollection of the problem: This started after a CMC swap was done by a local shop. (I was lazy and didn't want to do it myself) What it would initially do is jerk strongly kind of like an old manual car when you get on and off the throttle on take off, like when you're first learning to drive manual. I thought maybe the CMC was improperly adjusted as it had little to no play. I adjusted it and this problem went away or so I thought. Around this time I had also asked my tuner (DRob) for a revision with a little more mid range torque, which he provided. I had flashed the tune and later discovered that the car would stumble when given around 30-40% throttle around 4 or 5k rpms. It would basically cut throttle for a moment, you can let out of the throttle and put it back usually it feels back to normal. Went back to known good revision, problem still occurred so ruled out it being tune related. Lately it has started to do even more weird stuff, now when it has throttle cut out the audio system will also freak out and play sound only through the front speakers. The other day on the freeway I went to do a pull, and the car cut throttle more aggressively like traction control kicking in, the audio system also freaked out two or three times, and the brake light on the dash kept blinking. I limped it to my destination and as I was reversing the screen kept shutting off and on. This morning, I was driving the car went to roll my window down, and both the driver and passenger were lowering as I was pressing just the driver side button. The hazards also blinked twice as I was starting the car too. Couple other observations I've noticed is the car would only do this at part throttle before, only recently has it done it at full throttle. There is no knock or misfire happening in my datalogs so it doesn't seem mechanical at all.
I use to think this was something mechanical like misfires, but I am leaning towards maybe being a faulty BCM. I have no way of proving that though and I'm afraid to take it to a dealer only to pay a lot of diagnostic fees and they aren't able to reproduce the problem as the car acts and drives normal most of the time. Any ideas or insights would be appreciated.
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