Time to drive this CTR off a cliff

ebatr24

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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.
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DadBodMod17

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This may be a super basic/stupid thought, but would a battery or alternator dying be a cause for these electrical gremlins? Faulty electrical supply always puts a lot of ghosts in the machine from my experience. Would be stupid if it was something so simple... but maybe it's not at all related to the CMC work you had done?

Like I said... could be a super dumb suggestion.
 

AlphaDigital

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damn dude.

Im with you, I hate electrical shit. I hope you can get it figured out.
 

diakonia

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Do you have anything plugged into your OBD port? I had a GPS tracking device plugged into mine and it caused allot of electrical problems. It happened in another car I have too.
 

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What’s the time frame from the start of the issues to now?

If everything started after the CMC install, seems logical to check if any wires were accidentally spliced/crimped/grounded during install. Any nearby connectors the installers forgot to plug back in?

And the gremlins have been multiplying over time? Have you been washing the car? 🤣 JK, mate (for anyone who gets that reference).
 


Byron Sexton

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Yep you are going to have to work backwards from the CMC install...
 

wildbilly32

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Don't know what a CMC is but having been a railroad electrician in a previous life I would say go back to what was done to the car prior to it starting to act up. Most simple electrical troubleshooting place to start.
 

AlphaDigital

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Don't know what a CMC is but having been a railroad electrician in a previous life I would say go back to what was done to the car prior to it starting to act up. Most simple electrical troubleshooting place to start.
Clutch master cylinder. Funny thing is, I dont think any of that requires messing with the electrical system, so sometime must have been accidentally hit?
 
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ebatr24

ebatr24

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Clutch master cylinder. Funny thing is, I dont think any of that requires messing with the electrical system, so sometime must have been accidentally hit?
I am thinking it was just coincidental, I can't see any wires being damaged nearby to the clutch pedal when I went back to adjust it. I retraced it back fully as well as I had to basically reinstall it myself after the shop neglected to install my clutch line. Terrible shop, would never go back but I don't think they were quite that neglectful to not let me know if they broke anything that I couldn't see.
 
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ebatr24

ebatr24

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Do you have anything plugged into your OBD port? I had a GPS tracking device plugged into mine and it caused allot of electrical problems. It happened in another car I have too.
Funny enough today was the first day I thought of disconnecting my Hondata Flashpro from the OBD2 port, going to test out driving the car without the hondata plugged in. I always kept it plugged in to monitor the car and check any codes in case they ever popped up especailly with the car acting up but it never throws any codes for anything
 


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ebatr24

ebatr24

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This may be a super basic/stupid thought, but would a battery or alternator dying be a cause for these electrical gremlins? Faulty electrical supply always puts a lot of ghosts in the machine from my experience. Would be stupid if it was something so simple... but maybe it's not at all related to the CMC work you had done?

Like I said... could be a super dumb suggestion.
I've been checking battery voltage via the Hondahack mod on the headunit. Seems to be charging just fine to start the car, voltage looks good while the car is running as well usually see it above 14v. I always pay attention to the voltage when it acts up but nothing out of the normal from what I can tell. This isn't a fullproof way of diagnosing it, I just feel like I'd see other issues if the battery was getting weak or the alternator was on it's way out.
 

diakonia

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Funny enough today was the first day I thought of disconnecting my Hondata Flashpro from the OBD2 port, going to test out driving the car without the hondata plugged in. I always kept it plugged in to monitor the car and check any codes in case they ever popped up especailly with the car acting up but it never throws any codes for anything
Give it a try. After I unplugged my GPS tracker from the OBD all of my electrical problems went away in my CTR and my other car. I googled the issue and it looks like the problem is pretty common…
 

DadBodMod17

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I've been checking battery voltage via the Hondahack mod on the headunit. Seems to be charging just fine to start the car, voltage looks good while the car is running as well usually see it above 14v. I always pay attention to the voltage when it acts up but nothing out of the normal from what I can tell. This isn't a fullproof way of diagnosing it, I just feel like I'd see other issues if the battery was getting weak or the alternator was on it's way out.
Welp... I'm fresh out of idea's then... hope you are able to sort it out painlessly enough.
 
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ebatr24

ebatr24

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Give it a try. After I unplugged my GPS tracker from the OBD all of my electrical problems went away in my CTR and my other car. I googled the issue and it looks like the problem is pretty common…
Thanks, going to give that a try. I think my radar detector is also grounded on a bracket near the obd2 port, but its been that way for so long before any issues ever came up so I don't know what it's worth but I may try to relocate that ground too.
 

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Ok so from rereading your original post I see you think the clutch issue got better after adjusting the CMC play(or you think so). Then you jumped into a tune. Tune would be suspect #2.

Here's why I question the "tune mod"
"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."

Any changes are suspect...

I also agree with diakonia unplug anything you've got plugged into the car that isn't as purchased.

Please explain hondahack mod...?
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