Disconnected my battery foe a week,& and now she feels like a different car ?
#1
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Disconnected my battery for a week,& and now she feels like a different car ?
I went away for a week ,and rather than have to face a flat battery due to the poxyTracker on my 05 STI(ppp)on my return, I disconnected the battery for the time I was away. Now it may just be my imagination but the car seems to be really flying now , pulls so much stronger .Have I caused some kind of ECU reset(I seem to remember this was possible on classics), or am I just going bonkers ?
Dave
Dave
#3
when you disconnect the batery it resets the ecu. you then get max possible ignition advance and the car runs better until the ecu detects knock and then the ecu retards the ignition and performace is lost. the problem is the car will easily retard igtion but it does not advance it as easily and therefore a ecu reset cheats this.
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IIRC I was told that ideally you go out fully loaded and find a hill, then run up through third gear at wot, and the ecu will push the ignition timing as far as possible (safely !).
I also found that after a month of crawling to work, mine started (trying !) to be economical, and felt flat and farty.
HTH
dunx
I also found that after a month of crawling to work, mine started (trying !) to be economical, and felt flat and farty.
HTH
dunx
#5
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when you disconnect the batery it resets the ecu. you then get max possible ignition advance and the car runs better until the ecu detects knock and then the ecu retards the ignition and performace is lost. the problem is the car will easily retard igtion but it does not advance it as easily and therefore a ecu reset cheats this.
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Apparently if you reset ecu, then take her out to motorway find third gear, hold foot on brakr and push down on accelerator building up boost pressure works. Same general idea as the going up hill with full load on accelerator
#7
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Scoobypedia | Trusted knowledge for everything Subaru | Knowledge / ECU Fast Learning Trick
Article also tells the OP how the ECU learns ign.adv/ret.
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#11
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Believe me - you WANT it to retain its retardation feature!
Last edited by joz8968; 21 August 2009 at 10:01 AM.
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So is it best to go out and stick half a tank of shell v power in first before you disconnect the battery? How long do you really need to leave the battery off for?
#17
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Doing it by the connectors is the 'proper' way.
Yes, run the tank down and put in V-Power BEFORE you do the reset (and keep using it all the time, if poss). As when it's reset, and when you start driving, it'll immediately see 99 RON and you'll have optimal ign. timing after a period of varied loads on the engine have been applied. Hopefully it'll adv. to max (everything being okay.)
If you do reset via the battery, disconnect for at least 30mins. What I'd do is stick in V-Power late at night and disconnect batt. overnight, etc... lol
If you do reset via the battery, disconnect for at least 30mins. What I'd do is stick in V-Power late at night and disconnect batt. overnight, etc... lol
Last edited by joz8968; 20 October 2009 at 05:48 PM.
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does the early classics/wrx's ECU's advance/retard ignition timing as well or is it just the newages , just always wondered why the car felt a bit slower after resetting the ecu lol
#19
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Yes, all of the OEM JECS ECUs have IAM (ignition advance multiplier) feature, which has the ability to equally advance, or retard, from the reset's "middle" position.
So yes, when you did the reest, you would have retarded the ign timing back to your MY ECU's "middle 8" [sing it, lol] position - hence it feeling slower. Because before the reset, you would have invariably had most of, if not all, of the advance - up to the max of "16" (dependent on knock activity - if any.)
Don't worry though, it'll be fully optimised again within a few varying loads on the engine...
So yes, when you did the reest, you would have retarded the ign timing back to your MY ECU's "middle 8" [sing it, lol] position - hence it feeling slower. Because before the reset, you would have invariably had most of, if not all, of the advance - up to the max of "16" (dependent on knock activity - if any.)
Don't worry though, it'll be fully optimised again within a few varying loads on the engine...
Last edited by joz8968; 21 October 2009 at 12:03 AM.
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what your doing is clearing the kam memory. and dont forget about open and closed loop, full throttle uses the values from the chip, the ecu can only fine tune the map not remap it.
adam
adam
#22
With a newage ECU just disconnecting the battery for a bit won't reset the ECU. You need to perform a reset via a laptop or diagnostic device plugged into the EOBD port. Perhaps if you leave the battery off for long enough then it may well reset but generally speaking it has to be done electronically.
On classic scoobs leaving the battery off for a bit works as is well documented.
Best way to relearn values (this is what i do with my own and customers cars) after a reset is drive your car for a couple of mins then pull over and switch the ignition off for 30secs. Restart and go for another drive for another few mins, pull over and do the same again. Then restart the car, find a straight bit of unpopulated road and hold 3rd gear for 30secs at around 3500rpm, then build up the revs/engine load progressively and it should very quickly get to an IAM (Ignition Advance Multiplier) of 16 (16-bit ECU's) or 1 (32-bit ECU's - MY06+). You don't need to load your car up with gear to get there, just follow the process and it will work.
Unfortunately unless you have a laptop or diag device plugged in you can only tell if you're up at full IAM by feeling it.
Good luck
On classic scoobs leaving the battery off for a bit works as is well documented.
Best way to relearn values (this is what i do with my own and customers cars) after a reset is drive your car for a couple of mins then pull over and switch the ignition off for 30secs. Restart and go for another drive for another few mins, pull over and do the same again. Then restart the car, find a straight bit of unpopulated road and hold 3rd gear for 30secs at around 3500rpm, then build up the revs/engine load progressively and it should very quickly get to an IAM (Ignition Advance Multiplier) of 16 (16-bit ECU's) or 1 (32-bit ECU's - MY06+). You don't need to load your car up with gear to get there, just follow the process and it will work.
Unfortunately unless you have a laptop or diag device plugged in you can only tell if you're up at full IAM by feeling it.
Good luck
#23
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This is great stuff.
MY99 has seemed to loose something power wise. I'm taking it that the non mapped K+N will cause the ECU to retard thus the power loss. My car still pop's on overrun or coasting down hills (Lean?) so after fitting a standard airbox would this reset work for me?
MY99 has seemed to loose something power wise. I'm taking it that the non mapped K+N will cause the ECU to retard thus the power loss. My car still pop's on overrun or coasting down hills (Lean?) so after fitting a standard airbox would this reset work for me?
#24
This is great stuff.
MY99 has seemed to loose something power wise. I'm taking it that the non mapped K+N will cause the ECU to retard thus the power loss. My car still pop's on overrun or coasting down hills (Lean?) so after fitting a standard airbox would this reset work for me?
MY99 has seemed to loose something power wise. I'm taking it that the non mapped K+N will cause the ECU to retard thus the power loss. My car still pop's on overrun or coasting down hills (Lean?) so after fitting a standard airbox would this reset work for me?
Adding a K&N to a non remapped scoob will in effect lean it out. If you then remap for the K&N but later on change back to the std OEM airbox and filter it will run rich.
A proper remap will cure any popping and banging, and if your EcuTek dealer asks you if you want pops and bangs on overrun as part of your remap just say no, it's just so crap.
Edited to add: If your car wasn't remapped for the K&N then fitting the standard airbox and a std air filter should sort that as your MAF is scaled for the standard setup. Fitting a high flow flat panel air filter in the airbox may still give you the pops and bangs so K&N or high flow flat panel either way a remap is the way forward.
Last edited by scoobiewrx555; 21 October 2009 at 10:13 AM.
#25
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Popping and banging on overun means it's either still throwing fuel down the cylinders (like an Anti-Lag system) because the injectors aren't switching off on overrun, or more likely it's running lean. A proper loud backfire however would mean it's leaned right out, not good.
Adding a K&N to a non remapped scoob will in effect lean it out. If you then remap for the K&N but later on change back to the std OEM airbox and filter it will run rich.
A proper remap will cure any popping and banging, and if your EcuTek dealer asks you if you want pops and bangs on overrun as part of your remap just say no, it's just so crap.
Adding a K&N to a non remapped scoob will in effect lean it out. If you then remap for the K&N but later on change back to the std OEM airbox and filter it will run rich.
A proper remap will cure any popping and banging, and if your EcuTek dealer asks you if you want pops and bangs on overrun as part of your remap just say no, it's just so crap.
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