This isn’t 3rd Gen related but I thought I’d post here to get some feedback.

I’ve had the hardware/software to DIY Prom tuning for a while now (years, actually) but I never really got it out and tried using it until now. I figure the best way to start is to read the existing stock BIN, save it to the PC, load the BIN back to the buffer, write the stock BIN back to an EEPROM, plug it into the ECM and run it.

All this has gone fairly smooth. However, I have a problem and I’m looking for suggestions on how to resolve it.

The problem is that the engine won’t start with the newly burned EEPROM. I’ve also noticed that I don’t have a CEL with the key on/engine off. I’m sure the two are related.

Here’s the specifics of what I’m working on:

1992 Chevrolet Lumina
3.1L V6 Vin T
ECM: 1227727
Broadcast Code: AXKK
TunerPro V4.14
Moates USB AutoProm, GP1 Adapter
Mask ID: $A1

I’ve confirmed the following:

I’m erasing the EEPROMs before writing to them regardless of whether or not they’re already empty.

I’m writing to the correct buffer and EEPROM addresses for a 56k (57344 byte) file size (per Moates support site).

Buffer Address: 000000 ---> 00DFFF
Chip Address: 002000 ---> 00FFFF

The EEPROM are positioned and oriented correctly in both the AutoProm and GP1 adapter sockets.

I’ve checked to make sure the original memcal is plugged into the GP1 adapter correctly. I seem to recall reading someplace that if the ECM can’t read the resistor IC’s or whatever they are on the end of the memcal you’ll get a no start/no CEL condition; true?

The engine and CEL behave normally when I re-install the stock memcal into the ECM.

Any suggestions as to what I may be missing?

BTW, could this be an issue with the mask ID? The $A1 mask I’m using was downloaded from one of the EFI tuning sites (Gearhead??).

TIA

 

You don't mention what EEPROM you are using. The offset will be determined by the size of the EEPROM. You can eliminate this as a problem by using the FILL option when writing the bin to the chip and starting with no offset. Write the bin to the EEPROM and read it back to TunerPro to verify it was written to the top portion of the chip if using an offset. HTH!

 

The $A1 mask is likely correct for that vehicle. However, it is a 32 KB BIN (32768 actual bytes). So need to correct/change the buffer and chip offsets and such. If the BIN is actually 56K in size, it is corrupt. I would re-read the stock chip first and check it's size and integrity.

RBob.

 

Guys,

Thank you very much for the feedback and suggestions. It's much appreciated. I'll give it another go this weekend. Hopefully, I'll have better luck.

For EEPROM's, I'm using SST 27SF512's.

Thanks again.

 

Re-read the BIN from the stock EPROM; file size confirmed as a 32k file (thanks, RBob).

Erased and re-burned the stock BIN to the 27SF512 using the following addresses:

Chip: 008000 ---> 00FFFF
Buffer: 000000 ---> 007FFF

CEL on and started right up.

Thanks to everyone for your help.