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Discussion Starter #1
I have rallied many years, autocrossed, rallycrossed, and iced crossed VWs for many years and recently picked up a 2013 Focus and want to take it out on the ice. However while screwing around in the snow I am getting a mild engine cut while left foot braking which can be a real problem while pushing a car on loose surfaces haha. I have the traction control, abs, and yaw switched so that should not be the issue. Do these cars have a safety cut out? If so can I just inplug the brake sensor? I know the tail lights will also be unfunctional so I am trying to wait for a closed track to try that but someone has to know.
Thanks!
 

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These cars don't let you actually have fun. You never really disable the stability control and the car will pull power to correct itself anytime you slide.

Really, really super frustrating. Also kind of fun when you power into a turn way too fast and the car corrects itself. Just have to remember my other cars don't do it.

Sent from my XT1045 using Tapatalk
 

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Discussion Starter #3

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I'll go along with the first response, but add a bit.

My GUESS is that you can disable most of the nanny system by turning off ABS systems at the fuse, but the throttle cut functions of stability Control wouldn't be affected - as proven by your experiment.

Maybe tracing down the yaw sensor to disconnect it would be the answer to defeating that system entirely. (usually in the rear of the car over the rear axle area)
 

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Discussion Starter #5
Thanks I may have missed understood the first response. I will look into the stability wiring in the rear. To that point though the throttle cut also happens when going perfectly straight on dry roads as well though, I still think there may be more too it. We have a race this weekend and I will start unplugging sensors until something works I hope.
 

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There is a Brake-over-accelerator monitor in the PCM. Not sure how it would behave with the brake switch jumped out, but you can try. I would imagine it goes into limp mode if it doesn't like it.
 

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Discussion Starter #7
Anyone ever unplugged the speed sensor so the computer never knows you are going over 35mph which would disable the BOA? Not sure what else would be effected.
 

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The speed sensor usually inputs in for the engine load too, unplugging that might be a mistake.

I would have made a guess at this too.........

'There is a Brake-over-accelerator monitor in the PCM.'
 

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Discussion Starter #10
Thanks for the response. Yeah I don't like the idea of unplugging the VSS sensor either, that one has a lot of potential to screw things up.

I did pull the brake sensor and that worked fine but no tail lights which was ok for time trial stuff. Also, this needs to be tested more as the track we ran was very tight and speeds were not regularly over 35 so there may still be problems but they were masked by the slow speeds. Not sure.

I will look into the PCM and see what can be toyed with there.

Wish it just had the button you could hold down like on the trucks. Then you can just turn it all off at will like it should be.
 

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From the internet:
"Ford began migrating brake-throttle override, or Brake Over Accelerator (BOA), as the automaker calls it, in 2004 and the first product it appeared on was the 2005 Ford Escape Hybrid. By the end of calendar year 2010, it was implemented on nearly 100 percent of Ford and Lincoln light-duty models (excluding select low volume vehicles, such as certain trucks with a Cummins diesel engine). Owners of these trucks may not want BOA because they are backing up trailers or putting boats in the water, etc.

Brake Over Accelerator is a Ford-designed system. It is on manual and automatic transmission vehicles and operates the same. BOA is also on Ford hybrid and electric vehicles but operates a little bit differently than conventional powertrain vehicles. The system works the same way but the software calibration is a little different.

The BOA system monitors the accelerator pedal and the brake pedal position. If it senses brake pedal application and accelerator position not changing (for example, the accelerator is stuck or trapped), the electronic throttle is driven closed to idle position by the powertrain control module. As the throttle is driven closed, the brake force acts on the vehicle and it slows down—to a complete stop if the driver continues to apply the brakes.

Ford says that the system acts “very quickly.” When the brake is released, the system resumes normal operations, but the throttle is ramped back to the requested pedal position to allow a controllable acceleration. It also works in reverse."

Honestly, if you're using the car for racing I would try to contact Ford Performance and see if they have a solution for you. Might cost some money, but it may also improve functionality.
 

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Discussion Starter #12
Thank you for the detailed description, good information to know.

I will try and contact Ford Performance, an tune may be needed to get rid of it.
 

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A tune might help , I have been wanting to play more with the TQ settings

The Focus doesnt get its load from the speed sensor , actually I dont know of any Ford past 1999 that does , Load comes from the MAF

Tom
 

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Discussion Starter #14
Thanks for the help.

I did end up "fixing" the issue for a few ice races this year buy pulling a fuse and unplugging the brake sensor. However, you then have no tail lights.

I added a switch to the fuse under the hood that controls traction control and abs so that is easy to switch on and off now.

Looking into it I think there will be a way to add a switch to one of the wires in the brake sensor plug and turn off the signal to the computer while keeping the hard lined tail lights going. Project for when it is warmer. Unplugging that sensor is a pain due to location so a switch would make life much easier.
 

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i remember seeing some rally videos of Tim O'Neil LFB his Fiesta ST. curious what his solution was to the problem. (he also has Focus RS)
 

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Discussion Starter #16
From what I have read and seen, the RS has a button to turn all the "assistances" off, same with the ST I believe, but someone whom actually owns one might be able to chime in and confirm.

looked it up, the ST does have a button that will turn everything off; I assume the more sporty RS does too.

Thanks for the input though!
 

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I'm bringing this back because i need it. I found out that, I'm not well versed in terminology so bare withme, the brake plug from throttle to brake that applies the boa was taken out completely. I know the base fiesta at TON has no brake lights but the STs do.
 
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