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Disconnect battery for 30 minutes or so....
 

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Disconnect the battery, turn on the lights to discharge all the electrics. Set the timing at 7/10 degrees. Run hard for at least twenty five minutes. Reset timing to normal. This fools the ecu which re-learns, but doesn't know what the problem is. Hang on!!! Make sure you have very good, fresh fuel.
 

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Wow, never heard of that drive cycle before.
 

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NO! You do not have to change any timing or drive the car hard or what not. Simply disconnect the battery and wait 20 to 30 minutes. All "Learned" data will be wiped. Turning the lights on doesn't work the way you would expect because the lights are relay controlled and the relays drop out above the voltage needed to reset the ECU. If you have any large audio caps installed then disconnect that as well.
 

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Try it you'll like it.

I found this by accident in 1992 when I thought my stock racing motor was giving up and we changed motors. During the first practice session (25 minutes), the new motor performed about like the one it replaced. After checking it out, we found the timing was set at 5 degrees BTC instead of the 17 we normally ran. After reseting the timing, the thing was a rocket,I qualified on the pole, and won the race. This became a regular maintenance procedure every fourth race in order to keep the stock ecu in tip top shape.

The original motor had stretched the timing belt way out of specs in about two thousand race miles.
 

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Like I said... No need. The ECU "learn" function will reset with a proper power down and you don't need to go to the trouble of fooling the ECU into thinking something is wrong.
 

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not to thread jack... but could this be done by removing the MAIN battery fuse... big cable like fuse in the little black box in front of the battery?
 

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so.... does that fuse take all the power out? =P sorry asking again... but I'm not that savy when it comes to electronics in the Z
 

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There are several fusable links in front of the battery. One may (I don't have the schematics in front of me right now) but I'm not sure which. It's just easier to disconnect the battery terminal.
 

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Just have to be sure all the capacitors are drained. I always had a week or so between races so there was never a problem. You may, put on the brake lights, or open the door for the constant curcuit bypassing the switches.
 

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The 30 minutes is for a parasitic drain of all power to the ECM...

IF your not convinced ( and have a ecm hookup via laptop ) you can force an error code before you power down.. if the error code comes back you haven't let the ECM power down long enough.

I see the two different approaches... I use the pull the battery and wait approach.

Mike
 

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The approach that Racerbud uses is to fool the ECU into changing the learned value. It doesn't reset the ECU. If simply changes the base ignition/fuel offset. The better approach, in his case, would be to apply a better fuel and ignition map.
 

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The rules were STOCK ECU only. At 20/25 minutes in a practice session at 5 degrees BTDC the ECU compensated for what it didn't know was wrong, Fuel and timing. When timing was reset at 17 degrees it was already mapped. Dah!!
 

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On the street there are no rules on ECU setup other then emissions. No need for such tomfoolery on a street car. Another reason why: "What works on the track is not always what's needed on the street". It's also another reason I always liked SCCA’s SPO class. NO STINKEN RULES!:)

I think, in bigcg533's case, your suggestion does not apply.
 

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Interesting... the timing change issue rear's it's head again.. like I had.. Hmmmmmm.

Mike
 
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