General Fuel trims reset when I turn the car off.

[Nautica985]

I bought a EPROM ECU on ebay and it came with a "mitsubishi specialties STG-3 eprom chip".
There is a sticker on the ECU that says it was rebuilt on '02. The caps look new. Every time I turn the car off my fuel trims reset. Could it be the EPROM chip resetting the trims? The trims never reset with my non EPROM ecu

 

[larsrya8]

Are the trims the only things that are resetting? If everything is resetting, then there's a problem with the "memory wire" that provides power to the ECU memory when the car is off.

 

[Nautica985]

im not sure, how do i tell? I dont think its a wiring problem because the trims dont reset with my non-EPROM ECU

 

[Dred]

Take the MAF connector off the maf and start the car, that should give you a CEL. Shut the car off, take the key out, put the connector back on the MAF and start up the car again, if the CEL is off then the whole ECU resets not just the trims. If it stays, then it's just the trims. You can disconnect the battery for over 10secs to clear the CEL or w/ a logger.

 

[steve]

You should know that a mitsubishi specialties STG-3 eprom chip is a ripped/cloned off TMO stage 3 chip. It shouldn't be resetting the fuel trims so either the ECU is loosing backup power or they f'ed up the EPROM.

Steve