Interesting Focus ST thing.

Deleted User 234324

Deleted User 234324

Deleted User 234324

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Ever since getting my ST ive had appauling fuel economy (yes i know, i didnt buy the ST because its eco friendly!)

Anyway, prior to this little mod, i was getting an average 19.1 mpg, I do normal town driving, stop/start traffic over short distances (<10 miles)

Yesterday morning I reset all readings on the dash and drove to work as normal (5.7 miles) by the time I arrived at work my MPG was reading 15.8, drove home after work and it rose to 18.2.

So when I got home I popped the hood, removed the fuse box cover and swifting unplugged fuse 26 (known as the Keep Alive Memory Fuse).

Left it out for 30 minutes to clear the ECU memory, popped it back in and left the car until the following morning.

Well this morning, I jumped in the car and drove to work like normal, exactly the same trip, same distance but this time when I arrived at work the fuel economy had improved significantly (22.4mpg) and the car felt more responsive.

Turns out the KAM fuse retains information regarding fuel/performance and driving style.

By removing it for 30 minutes the car looses all information about your driving style and has to relearn. So if you bought the car from someone who had a very heavy right foot, you may find that removing the KAM fuse will drastically improve the fuel economy of the car for someone who potters around town all day or if you bought the car off a granny and want the maximum performance from the car, do the same and drive like you stole it after removing the KAM. The car will adjust and remember you like to give it some beans.

More detailed information can be found on focusstoc.com, certainly made a difference for myself and others.
 
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I don't think that's just restricted to the ST. A lot of cars will relearn after losing power for a certain amount of time.
 
EP3 Type-R benefitted from that (and also other K20 engined cars I would assume).

I wouldn't be relying on the cars computer of your real life MPG though, I would be doing the sums at the pump for a proper comparison.
 
I have read about this for a number of cars but I always thought that these settings were constantly being adjusted as you drove?

I also really love the ST but if I get sub 30MPG in the Octavia on anything over 5 miles I slap myself around the face :p
 
Its worth doing this before and after track days to get the most out of the car on the track rather than using your daily drive profile.
 
I thought that the mpg display was always being adjusted, and I never knew that cars kept a memory of driving styles and adapted to it.

Is this doable on an e46? As the previous owner drove very, very carfully and I've always suspected my car to be slower than it should be. How would I find out?
 
More than likely does, but its finding the correct fuse to pull, maybe that in your car the same fuse is used for other parts of the vehicle.

The other option is to disconnect the car battery for 30 minutes, but DO NOT do this unless you know the security code for your vehicle.
 
I know that my E46 learns on the fly. I drive it like a grandad most of the time, so when I get in it and the throttle response has sharpened up, it's usually because my missus has just driven it rather enthusiastically.

Ref your fuel economy change, surely the ECU will have forgotten about how a previous owner drove if it's over a period of months or longer?
 
Mr_Sukebe said:
I know that my E46 learns on the fly. I drive it like a grandad most of the time, so when I get in it and the throttle response has sharpened up, it's usually because my missus has just driven it rather enthusiastically.

Ref your fuel economy change, surely the ECU will have forgotten about how a previous owner drove if it's over a period of months or longer?
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One would assume that yeah, but it hadnt, in the 5 weeks i've owned the vehicle having covered roughly 700 miles in that time with a mix of town and motorway driving and resetting the mpg average every fill up, i'd never had above 20mpg and dont drive with a heavy right foot.

But after doing the above within 6 miles ive got above 20mpg. Apparently its also something worth doing when ever you modify the car in anyway that could affect performance/enonomy or emissions
 
As I mentioned, no idea, but the alternative to removing just the fuse is to disconnect the battery for 30 minutes.

But only do that if you know the security code for your radio. If you don't know it and disconnect the battery, your radio will stop working
 
Sounds like another use of totally useless technology. What is the advantage of this? Seems like it serves no other purpose than to kill fuel economy?
 
Not really, call it a "memory cache" if you must, basically every day things that the car does are held in memory for quick access, rather than burdon the ECU will work.

So your car knows essentially knows that if your in 2nd gear, doing 30 mph you will use xx amount of fuel. Instead of your in 2nd gear at 30mph and will plant your foot to the floor so overfuel by xx amount.
 
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The quote there sounds like it's just a normal self-learning system like EFi cars have had since the year dot, nothing special and nothing to do with adapting to driving style. Maybe I've understood it wrong but that's how it looks to me.
 
Clarkey said:
The quote there sounds like it's just a normal self-learning system like EFi cars have had since the year dot, nothing special and nothing to do with adapting to driving style. Maybe I've understood it wrong but that's how it looks to me.
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That was just something I copy pasted from google, probably not that accurate or even the correct information for the Focus ST which im basing this on.

Here is what a guy on focusstoc.com said about the KAM and why it exists.

focusstoc.com said:
KAM is needed as a predictive strategy learnt as you drive, without it next time you come to a halt/corner etc there would be driveability concerns eg idle hang, as the PCM wouldn't have learned what was done last time the same circumstances occured. Also any fault codes wouldn't be stored so making diagnostics hugely difficult.
Click to expand...
 
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MadMossy said:
Here is what a guy on focusstoc.com said about the KAM and why it exists.
Click to expand...

Sounds just like a typical adaptive (not predictive) fuel and idle trim. Take any modernish car with EFI, erase these trim values by pulling a fuse/disconnecting the battery and the car is likely to idle poorly and likely give different MPG until it has re-adapted.
 
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