Oilslick964

I have an 01 996tt and, prior to my buying it, it had the engine computer re-mapped and it was crazy-fast! Last week, my alternator gave up the ghost, so I ordered a new one. The car sat for 3 days with the battery disconnected until I got my new alternator. I changed out the alternator and now, the car definitely does not have the power it had before. Is it possible that the computer reset itself to the factory setting while the battery was disconnected? By the way, here is my car. 01 996tt with GT2 body kit, flat black vinyl wrap with carbon fiber accents, black powder-coated wheels. Pretty fast but slower than it was last week!

Macster

The ECU loses its learned fueling when power is removed. It will take a bit of driving for the ECU to relearn.

The remap might consist of storing special/custom fueling timing map data into the map area. If so this is a new one on me. But if this is the way the remap works then yes it is possible that while power was lost this special/custom map data went away.

Though I wonder what it to keep it from going away, being overwritten, as the engine is used and as driving/climate conditions change?

Anyhow, you might want to check in with the company that sells the remap and see what you can learn. If the remap has indeed been lost from no power maybe the company will help restore what was lost for free?

Sincerely,

Macster.

Oilslick964

Thanks Macster! I just read this after I came in from driving the car and I am happy to report that it is operating perfectly! I was not aware of the re-learning curve! Whew! I was scared, there for a minute but I am happy, happy that this was a false alarm!!!

Kevinmacd

The map is usually hard coded with the timming, boost and fuel maps. What happens is power is lost, as said the ECU needs to relearn the driving characteristics! Once it does the hard encoded mapping will have a baseline to expand on.

Macster

That's good to read. I was not very confident the 'remap' simply wrote some special info into volatile SRAM.

Your driving the car allowed the ECU to relearn and adapt to the engine's characteristics and all should be fine going forward.

Probably not a big issue but since power was lost you probably want to reset the limits of the door windows.

Also, the e-Gas needs to be given a chance to recalibrate.

IIRC, with the key off and your foot off the gas pedal, turn the key to on. Leave the key on for 60 seconds.

Turn the key off for at least 10 seconds.

Then you can start the engine. The e-Gas has been recalibrated.

Sincerely,

Macster.

Oilslick964

I did the windows but was unaware of the e-Gas calibration. Will take care of that right away. Thank you very much! You have been a big help!!!

SteveMFr

It would prob be good to know who's tune you have. Maybe you can try contacting the PO or some of the re-mapping co's to see if they have your VIN on file.

If your car has an APR tune it may have reverted back to the original file as the tuning maps are switchable:
http://www.goapr.com/products/ecu_upgrade_996turbo.html
(see about halfway down 'available features>program switching')