I am working on a friends prom in his '86 Camaro LB9. It of course has the '165 computer with $32 code. I remove the prom and erase it, just barely noticing the AMU broadcast code on the foil sticker. I think nothing of it. I write the new bin with $6E code and attempt to program it to the prom. It does not even start, instant failure.

I check to make sure GM didn't put a 32K eprom in and they didn't. Sometimes they do even in MAF cars.

I then research the AMU BCC and find out it's 4K bin, not a 16K bin as expected in a '86-89. In fact the whole AMU series is 4K. The netres chips are even different in this AMU memcal.

I know the '85 used a 4K bin. Anyone run into this before?

 

John, doesn't sound right to me. The ECMs using 4KB chips typically have another 8KB in on-board ROM. The '165 doesn't have ROM for this purpose (at least AFAIK).

Check to see if the chip is a 256kb (32kB). If so then either need to double stack the bin or offset the burner buffer to the upper half of the chip.

RBob.

 

It didn't sound right to me either. That's why I posted here. GM does strange things. The AMU BCC says 1986 LB9 but the manufacture date is late '85 so it COULD be a 4K eprom I think if they carried it over from the '85 ecu (I know the '85 was a direct eprom, no memcal).

I really don't think the eprom is a 32kB chip, the ones that were on a MAF car stated so on the top (27C256). I haven't determined the manufacture or size of this particular eprom by the few numbers on top.

Lastly, I need to look at the AMU BCC's and see what Tunercat $32 reads them as since they're only 4K in size, it might not even open. If it does open I am curious as to what's different...........

 

I wish I would have saved AMU.bin now. I don't have absolute proof that it is in fact a 4K bin or not. I am guessing it is because the others in the AMU series are 4K bins but most are LO3 engines, not LB9's......


I have the following info directly off the eprom on the memcal. Can someone tell me what size it is(type)?

16040581
796 K
8602 5010

 

Count the pins on the EPROM. A 4 KB (32 Kb) EPROM has 24 pins, the 16 KB (edit: 128 Kb, not 64 Kb as originally posted) and 32 KB (256 Kb) EPROMS have 28 pins.

RBob.

 

That's not a true statement. Memcal cars have 28 pin eproms.

A 27C128 (16K) eprom has 28 pins

1 27C256 (32K) eprom also has 28 pins

 

He just said that, re-read it and you just repeated what he said.
As for the memcal's, they all are 28-pin meaning they're all at least 16k or larger. The 24-pin chips GM used are 4k and that 4k was full of calibration look-ups, not actual code, maybe a little be very little. The on-board rom has the code and it's 8k full of stuff. I HIGHLY doubt that GM got all of the $32 code on a 4k chip AND had room for the speed density tables. They just wouldn't do that.
Use a hex editor to open the saved bin and do a checksum. Also the mask ID should be at the top.

 

Then the EPROM in question is one of these, not the 4K. Note that I edited my previous post from 64 Kb to 128 Kb. This is what matches the 16 KB EPROM size (bytes & bits, glad I kept nybbles out of it ).

(For anyone wondering about the different Kb/KB's: upper case B is bytes, lower case b is bits).

RBob.

 

AMU is from a 1225330 ecm.
A, AUM is from a 1227615.

HTH