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Old 04-25-2004, 11:08 PM   #126
Turb0flat4
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Does this have to be done immediately after an ECU reset without going into boost before the procedure.

Or is it OK to do it after you've been driving (normally, hitting boost on and off) for a day or so after an ECU reset. The car still feels slightly rough, so can this procedure still be done (without another reset) to smooth things out ? Or should the ECU be reset again before doing the process ?

Thanks a lot.
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Old 04-25-2004, 11:26 PM   #127
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reset it...
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Old 04-29-2004, 02:44 AM   #128
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Can you do this if you have an Accessport?
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Old 04-29-2004, 12:24 PM   #129
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Quote:
Originally posted by killermike
Can you do this if you have an Accessport?
I would think you should be able to since accessport retains the learning functionality of the ECU. Might not get the 10-2hp but you should maximize the accessport map you are using. I havent tried it yet though.
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Old 04-29-2004, 08:32 PM   #130
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A few observations if I may...

Most forced induction Impreza ECUs from MY99 to 2004- operate an advance multiplier. This limits the maximum amount of POSITIVE knock correction the ECU can apply. There is virtually no limit to negative correction.

A happy ECU should normally be at 16 or very close. If you reset an ECU that's already at 16 the result will invariably be a loss of power (which will be restored over the next 50 to 200 miles). If the ECU isn't already at or near 16 then there's something wrong with the fuel, map or engine. Duff fuel can cause the multiplier to drop and sometimes it gets "stuck", in these cases a reset can help.

Learning procedure is heavily car dependant. New Age WRX models learn really quickly between 3000 and 4000 RPM at 0.5 bar. MY99-00 turbo models don't need much boost to learn. MY99-00 STi models need a good 0.7bar to learn, and will normally jump to 10 first, then 12 then 16. New Age STi models like to learn going up through the gears rather than being held on a particular load. They also like to idle for a while, stood still and out of gear, after a reset before they want to "play".

There are additional criteria for learning, such as coolant temp, VVT operation etc. Each model has its "sweet spot", if you can get it there it will learn in 200 yards or so, if not it can take ages (notably STi models are a bit more fussy).

The learning makes more advance available. Typically the ECU should be adding at least 8 degrees on top of the base timing in the midrange. This is close to the limit of the stock maps, so with a multiplier of 8 it would be limited to about 4 or 5 degrees. Getting the multiplier up to 16 will allow another 3 or 4 degrees, which can be worth another 30 lb/ft.

A car that has a really low multiplier will feel "flat" or "hesitant" in the midrange, but this typically clears up over 4500 RPM. It may feel like a slight misfire, but it's just a lack of timing.

Bottom line is, if it feels wrong, it probably is. If it feels OK-ish then check the multiplier, if it's already 16 then leave well alone, if it's less then reset and keep an eye on it... if it falls down again use different fuel or remap.

Cheers,

Pat.
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Old 05-05-2004, 10:57 PM   #131
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what will this do for a completely stock wrx? i am planning to do this tonight?
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Old 05-06-2004, 03:23 AM   #132
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Quote:
Originally posted by surfer5567
what will this do for a completely stock wrx? i am planning to do this tonight?
it will do nothing but "reset" your car to max timing advance, which is useful if you've recently run a bad tank of fuel.

It will take some time for the fuel trims to stabilize once again so it won't be perfectly smooth for quite some time still.
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Old 05-06-2004, 05:21 PM   #133
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Quote:
Originally posted by surfer5567
what will this do for a completely stock wrx? i am planning to do this tonight?
If I haven't had a bad tank of gas, will the resetting of my ECU help anything? or should I leave it as is?? (total noob btw)
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Old 05-06-2004, 06:55 PM   #134
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Unless something has changed with regards to the car in the last 1000 miles it won't do you any good. Fueling has been learned and timing has already set to your driving style and fuel quality. This "trick" is to advance the timing quicker than it would by driving around but in 1000 miles it will end up in the same place whether this "trick" was done or not. It is used primarily when a reset has been required because of a modification or has occurred for other reasons.
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Old 05-07-2004, 10:48 AM   #135
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Quote:
Originally posted by turboICE
Unless something has changed with regards to the car in the last 1000 miles it won't do you any good. Fueling has been learned and timing has already set to your driving style and fuel quality. This "trick" is to advance the timing quicker than it would by driving around but in 1000 miles it will end up in the same place whether this "trick" was done or not. It is used primarily when a reset has been required because of a modification or has occurred for other reasons.
Thanks!!
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Old 05-09-2004, 04:34 PM   #136
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Ok, I am a total noob so please go easy on me. Let me know if this is how you do this?

I drive the car till it warms up. ( I HAVE A STOCK ECU BY THE WAY) Then while the car is still running disconnect the negative terminal and leave it unhooked then drive the car not getting into boost. Take off in 1st a little bit not getting into boost, then shift into 3rd and maintain 2600 for 5 secs or so. Then pull over and reconnect the negative terminal and go on down the road a little happier. Is it really that easy and is this correct way of doing it? Thanks
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Old 05-09-2004, 06:50 PM   #137
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No, your car will not start without the battery connected. Disconnect, reconnected, and then perform the procedure.

As a side note does anyone know how to pull the current value its at?
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Old 05-09-2004, 06:55 PM   #138
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No. Warm car. Turn off car. Disconnect battery. Press brakes. Reconnect battery. Turn car on. Get going to a normal speed pick a gear that is between 2500 and 3000 rpm at that speed. Using your left foot on the brake maintain the rpm between 2500 and 3000 rpm while getting boost between 5 and 10 psi for 5-10 seconds. It doesn't even have to be continuous you can do it for 3 seconds 3 different times.

But at least understand what this is about. When you reset the ECU it goes to a base state of fueling and timing. All this does is advance the point from which timing well be learned again by the ECU. It will not make your 227 hp car 243 hp. Basically a reset ECU is a tune that is around 210 hp and as learning occurs it increases if you are running good fuel. If you have been running the same gasoline for a while and do this you will end up pretty much back at the same place. This trick is done for when you have made modifications to the car and the ECU has to be reset because of it - but you want to do a dyno run right away, not wait until after you have driven 500 miles.

Delta Dash will pull what the current value of the advance multiplier is - but thus far it does not have that value for the US STi's though . I do not know if other scanners can - it is not part of the OBDII set of information.
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Old 05-10-2004, 08:29 AM   #139
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Made it a Sticky.......Good Stuff Shiv...

thanks
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Old 05-11-2004, 04:44 PM   #140
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Good idea to make this a sticky to help individuals in the future.
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Old 05-11-2004, 06:29 PM   #141
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Thanks Shiv
I have two questions:

Why does it has to be made at 2600 rpms?
Do you think that will work on my Eurospec 2004 STI?
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Old 05-21-2004, 12:49 AM   #142
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Default Re: Re: Re-Mapped ECU Learning Trick 10-20hp in 5 seconds :)

Quote:
Originally posted by AZScoobie
Wanted to just state that left ft braking while in boost will drain the vac from the brakes power booster. This will cause the brakes to have no power assist.. Wont hurt anything.. just beware that you might not have strong brakes until you get back into vac.. I found this out on my car while doing some road tuning the otherday. Just FYI.

CT
OK. Let's think about what we're trying to achieve here. Do this while imitating the Monty Python Gumbys (they're the ones with the handkerchiefs on the heads and the wellington boots...) "if you press the brake pedal to restrict the speed while you press the throttle pedal at the same time it doesn't matter how much power assist you have... You are not trying to stop the car, you are only trying to stop it going faster..."

______________________________________
"You put one foot on the accelerator and one foot on the brake. It doesn't matter which one you press, as long as you press it HARD!" Pentti Arrikalla
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Old 06-08-2004, 09:15 AM   #143
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i've got an '04 with 2600 miles on the odo. i did this with the stock ecu. Seeing as how the ecu "learned" during the breakin period I noticed a difference. Good tip!
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Old 06-29-2004, 02:43 PM   #144
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I can't see a reason why it is NECESSARY to do the ECU reset to make this work. Anyone wanna weigh in?

Dan
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Old 07-02-2004, 10:33 AM   #145
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I don't know but will guess anyways. If the ecu has 1000 hours of driving on it, then 5 seconds is about one millionth of that time. So the ecu would be comparing a point in time equal to one millionth to the rest of the time it has been working. It probably won't make any changes. Now, if it is reset, 5 seconds represents a higher percentage of the time the ecu has been managing the engine and significant enough to warrant change. But that's just applying logic. In truth, I have no idea if this is the way these things work.
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Old 07-02-2004, 03:22 PM   #146
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That's not true. The trick will work fine on an ECU that was not recently reset. The important thing to remember is that if for some reason your ECU has a low IAM without being reset, forcing the IAM to max may cause detonation if you don't know why the IAM was low in the first place. If all is well, the IAM should not be lowered by the ECU after a lot of driving time. That's why its really only a good idea to force it to max after a reset.

-- Ed
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Old 07-20-2004, 04:03 PM   #147
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sweet im goin to try this today will this still work with an auto wrx?
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Old 07-20-2004, 10:42 PM   #148
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I don't think it will work with an auto... I'd expect your tranny to down-shift with that much load at that RPM.

-- Ed
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Old 07-21-2004, 12:32 AM   #149
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Quote:
Originally Posted by Vaus
I don't think it will work with an auto... I'd expect your tranny to down-shift with that much load at that RPM.

-- Ed

Ed,

Can you confirm that this still works on a 2004 in the same way and to the same degree?
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Old 07-21-2004, 04:31 AM   #150
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can't confirm it, sorry

-- Ed
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