I have the stock GM Memcal and one with the ADS superchip, both modified with sockets to swap Eproms easily. I started with the ADS memcal, since I put a ZIF socket on it. I started out by making a copy of the GM prom and another of the ADS prom, just to see if everything worked.

I started the car with the ADS memcal, and th e GM chip copy. The car ran, but not very good, and the SES light stayed on. It probably was running in "limp-home" mode. I could not get any codes out of the ECM either. I tried my stock chip, as well as the original ADS chip, and the same results.

So, I pulled that memcal, and tried my GM memcal with the GM chip in the socket. Car ran fine with no codes. I also tried my 2 "newly" burned chip copies, and they both worked fine. What could have happened to the ADS memcal? Do they go bad, or perhaps maybe I damaged it during the work I did on it?

Now another question, is it ok to swap EPROMS and/or memcals with battery voltage applied to the ECM? (key off of course) I don't think it would hurt anything, just wanted do get some opinions. Thanks.

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It will not "hurt" anything electrically, but you want to unplug the computer for at least 10 seconds to clear the ram. Ohm out your memcal pins to zif socket, should find prob there.
-Carl

 

Some people will tell you it'll "hurt" your ECM to swap chips while the battery is stilll connected, but as far as I'm concerend as long as the key is off, the ECM is turned off, so it's safe. I've done it for a few hundred times on my car with no problems... hehe

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Thanks for your replies. I guess I could unplug the power fuse for the ECM, since it is easy to get to. But I will most likely just swap out the eproms with the key off, and everything else connected.

I found the problem with my ADS memcal and ZIF socket soldered in. The socket itself had 4 sockets bridged across on 1 side, and 2 bridged on the other. These were on the top of the socket where the chip goes in. It was definitely a manufacturing defect. I kind of figured that the ZIF was a low-qualitiy socket. Just have to check everything out twice over I guess. An exacto knife fixed it easily. I tried that memcal in my car tonight with 2 different eproms, and it worked fine.