Resetting the ECU

The G-Series Tuning Forum is the place to discuss G35/G37 performance modifications and mechanical repair.
DJames
Posts: 21
Joined: Wed May 07, 2003 11:41 am

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Hi i just got my Injen CAI Intake and i love it but i heard that if you reset your ecu you can feel more gains but im worried that something might happen to the car... does anyone know if it will hurt the car ?? has anyone dones this afte installing the Injen CAI if so please reply so i know what to do ?? and how do you restart the ecu anyways ?? please help i need it :(


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DAEDALUS
Posts: 6230
Joined: Mon Jul 22, 2002 8:50 pm
Car: 1990 Q45

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It shouldn't hurt the car at all, but I'm skeptical you'll see any gains, since the car is supposed to learn while running. The safest way is probably to disconnect the battery for 24 hours. This should be long enough for the power supply and the ECM PROM chip to power down and lose memory. The next time you run the car it'll begin to relearn all over.

vq35de
Posts: 211
Joined: Fri May 16, 2003 4:20 pm
Car: G35 Sedan Leather 6MT

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http://g35driver.com/forums/sh...part=

read and do the last post. email me with questions

Sean

Aries
Posts: 2887
Joined: Tue Aug 27, 2002 6:23 am
Car: LT1 240SS
Contact:

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the car will learn the new setup in about 10 minutes of driving.No big deal.

DJames
Posts: 21
Joined: Wed May 07, 2003 11:41 am

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man those instructions look to hard to do .. :( i just unpluged the wire from the battery for like 10 min and kinda seems better but also kinda the same eh :( this sucks only if someone knew a lot about cars the lived near me lol thanks guys for the help

vq35de
Posts: 211
Joined: Fri May 16, 2003 4:20 pm
Car: G35 Sedan Leather 6MT

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Aries, this ECU will not learn the new setup in 10 minutes.

it takes a few day to adjust to a new catback exhaust, and a week or more for larger mods such as a full exhaust.

Now if you drive it hard ALL the time it will take less time to see peak performance

personally, i prefer the 24hr disconnect method and don't like thios method, but he asked for info and i gave it to him

this is why people say the car has multiple personalities and why the wide array of 1/4 times as well as the ability of the sedan to beat the coupe and the Z on certain days but not others.

The ECU is weird man

DJames
Posts: 21
Joined: Wed May 07, 2003 11:41 am

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thanks for your help .. maybe my cars just needs more time to learn it all :(

Aries
Posts: 2887
Joined: Tue Aug 27, 2002 6:23 am
Car: LT1 240SS
Contact:

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sorry, I was under the impression that everyone drove their performance vehicles hard!?!?

My computer reset and saw significant improvement to the catback and intake system in very little time because I do drive it hard.

The harder you drive these cars, the quicker the ECU adjusts.

DJames
Posts: 21
Joined: Wed May 07, 2003 11:41 am

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so how hard did you drive your car ... at wat rpm did u go up to and switch ?? ...

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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Usually 10-15 miles at 55 mph is all the ecu needs to reset. When this EPA "driving cycle" is complete the ecu "flags" ok for emission test. No need for WOT as this is not tested or stored or modified only the idle and cruise rpm are trimmed for emissions.

The exact driving cycle is delinated in your FSM.

This is necessary so that you don't just "reset ecu" outside the emissions center and try to pass that way. The "Flag" tells on you and you fail automatically.

Lots of this self learning has been way over hyped as it is a requirement of all OBD2 ecu/tcu.......some try to place a more postive performance spin on it.

In 2000--2002 O2 sensors were changed to be more "Wide Band" more sensitive [more expensive] to read idle and cruise and higher rpm.....[Still not WOT at or above torque peak but closer]........not just cruise as before.

The greatest problem with aftermarket intakes is that the MAF was calibrated [the voltage the ecu sees and uses in the calculations] for the factory intake.

Other intakes make not create the exact SAME swirls and vortex the oem unit did, so the MAF gets fooled in thinking more or less air is flowing.............the aftermarket might [?] have a lower restriction but the MAF thinks it's worse..............anyway it's not what the ecu expects from it's preprogrammed value: vs. rpm vs load vs. temperature, etc.

As long as the oem stock air filter stay in place/ in position [to straighten shape the air flow] what you do in front of the filter matters little to the MAF.

Many of the aftermarket intakes take advantage of these errors, by making the MAF see less air the ecu leans the mixture slightly reducing the over rich [safety reserve] creating a few more horsepower.

A scan tool monitoring the MAF [ecu translated] into grams per second will tell you whats happening - good or bad.


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