Hi, I am getting ready to start burning my own eproms. I am in the middle of converting to a speed density system from my 89 maf sytem. I want to use a piggy back chip but it doesnt appear to be very easy to find cheap used ones for speed density systems. Will the piggy back chip meant for a different chip work? For example, would a piggy back chip from an 86-89 work for a 90-92? I would be replacing the eprom with an $8D programmed chip first of course, I just want to know if I can use the piggy back adapter. Also does anyone have the part number for a stock speed density chip?
Thanks,
Mike

 

IF your talking about the green type like hyertech uses then yes you can use that. When you install your old memcal that supplies the netres and stuff, then ignores the oem eprom, and reads the one that is in the new socket

 

I cannot give you the actual part number, but the current SD memcal for a 350 F-body is AUJP 1615. It is the replacement for the AUJP 1350 that came in my car. They are identical except for the date and sequence number.

If you do use a "Piggy back", make sure the eprom in the piggy back is a 27C256 or (better yet) an AT29C256 Flash Prom. Also, you may have to "open the window" up in the actual ecm's case. I dismantled mine and ground the "window" wider to make it easier to r&r.