Please help, Code 41 with GM1 Memory Adapter and new prom

Hello all!

I'm new to PROM burning and could use some guidance. I have a 1987 Corvette with the 1227165 ECM I'm trying to use with a newly burnt PROM. I am using the BoostedNW GM1 Memory adapter to attach the PROM and have the original MEMCAL piggybacked. I've only made slight changes to the bin to disable EGR.

When I start the car with this configuration, it fires right up, but I immediately get a Code 41 and it idles really rough (like it has a loppy cam installed). From searching the details of Code 41, I believe that this means the ECM can't communicate with the new PROM.

I've verified that the issue goes away when I remove the memory adapter and install the original memcal. I've tested burning the chip both with the bin copies from the original memcal as well as a bin found online and got the same results. When I burn the new PROM, I'm using what I believe are the correct offsets for a 16K bin.

Any thoughts on what could be causing this issue? At this point I'm wondering if there is a problem with the memory adapter from boostednw.

Thanks in advance!

David

Here is a thought: do I need to do something with the checksum or Prom ID? I've read that I may need to set the Prom ID to aa to disable the prom checksum validation.

What offsets were used when the chip was burned?

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Originally Posted by dave w

What offsets were used when the chip was burned?

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It's a 27SF512 PROM and the offsets are:

Buffer 0000-3FFF
Chip C000-FFFF

Thanks!

I'm testing using tunerpro to stack the bin as well, and getting the exact same results.

I'm starting to wonder if the PROM is maybe backwards, but I've verified with pictures from boostednw that the orientation seems to be correct.

Does installing the original Memcal, without the adapter board / new chip, cause the error? I'm guessing no.

If no, then the error is being caused by the installation of the adapter board and / or new chip.

Is the chip programmer set to program chip 27SF512, likely it is. Checking the basics chip orientation, chip programming, chip type and offsets.

Attachment 19580

Quote:

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Originally Posted by dave w

Does installing the original Memcal, without the adapter board / new chip, cause the error? I'm guessing no.

If no, then the error is being caused by the installation of the adapter board and / or new chip.

Is the chip programmer set to program chip 27SF512, likely it is. Checking the basics chip orientation, chip programming, chip type and offsets.

Attachment 19580

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Thanks for your response!

Removing the adapter and reinstalling the memcall does resolve the issue. The orientation is the same as the image you posted, but I'll review just to make sure.

Ok, so I did a bit more testing.

I removed the PROM altogether (left in the adapter and the piggybacked memcal) and ran the car and had the same symptoms. I also tried rewriting the PROM and confirmed the offsets, giving me the same symptoms. When reinstalling the PROM, I verified that all the connections were good and that the orientation matched the picture above.

At this point I think these are the options:

1. The memory adapter is faulty, and not allowing communication between the ECM and PROM. The adapter is brand new, so this doesn't seem likely.
2. There is something wrong with the way I am writing the .bin the PROM. I've confirmed both the offset and tried stacking, but there might be something else that I'm missing.
3.The prom is faulty, but this is also new and doesn't seem likely.

I also removed the adapter altogether and reinstalled the memcal directly to the ECM, and verified that the issue completely went away.

I'm leaning towards #2 being the issue, and that I'm still doing something wrong with writing the .bin, but I'm at a bit of a loss for what I could be doing wrong. Is there a checksum that I need to be updating?

Thanks again for your help, I'm open to any other ideas.

Interesting read on chips: http://www.gearhead-efi.com/Fuel-Inj...price-increase

The Boosted NW Chip Burner is supposed to allow burning second source 27SF512 chips (aka Fake Chips). There are several variants of the 27SF512 Chip and not all "budget" chip programmers work with all 27SF512 variants.

Possibly the Boosted NW Chip Burner requires an additional step that the chip be manually erased before the chip is burned? Seems likely the Boosted NW Chip Burner would provide an error message "Chip Not Blank" if attempting to burn a chip that has not been erased. Possibly the Boosted NW Chip Burner requires a manual step to verify chip programming, "verify chip with buffer"?

The chip programmer I use, Batronix BX32 Batupo II, will automatically erase the 27SF512 before the chip is burned and automatically verifies chip with buffer after burning the chip.

Possibly post a screen capture of the Boosted NW Chip Burner setup when burning the chip. Possibly the Buffer addressing, and Chip addressing is transposed?

Possibly try burning another chip?

Quote:

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Originally Posted by dave w

Possibly try burning another chip?

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Yep, that was it! I had a second chip that I tried burning, with the same steps, and I was able to fire it up this morning. It's idling great and not throwing any codes.

Thank you for your help, I really appreciate your knowledge and insights.