I have noticed in tuning a couple of cars (with LS1 Edit) that the cars that are 01-02 idle extremely well with big lift cams compared to the 99-00, (or maybe it is just me). I have also noticed there are more information in the factory tables (01-02) than there is in the (99-00) tables. I was having the hardest time trying to get the surging out of a 99 TA and no matter what I tried it would not come out. I then put a 2001 pcm in the car and tuned it the same way I did the 99 and the car idles perfectly.
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there are more tables, more resolution in many of the tables, etc...obviously there were many mechanical changes as well from 99 to 02 so many of the tables have different values as well.

 

It would probabably be from the spark idle error correction?

 

So, can GM program a 99-00 computer to the 01-02 tables?

 

They can, but they won't. When the GM engineers issue an update for your model year that requires a dealer to reflash the PCM, I would assume they started from the last 'good' tune in their files for that model year. They would create more problems than they would solve if they loaded an '02 file into an '00 car.

 

one has the 512kB cache and the other has the 1024kB cache? Are there fundamental differences between these two? How about processing power, sampling rate, optimization?

 

as far as I know 99-02 were all 512kb...03+ is 1024 though

 

2003 corvette is still 512k right?

 

I thought they were 1024 thats why RoadRunner requires a new pcm for 03+ vehicles? I'll double check though.

 

I came upon a 03 ZO6 six months ago that had the 1mb pcm in it. I couldn't put my 512k RR in it. Different connectors. 512=red/blue 1024=red/green

 

looking at all my files, it looks like the 2003 vette is 512k

 

yeah, looks like your right Jesse...guess its just a different connector issue.

 

thanks for all of the replies.
Since the 2001 computer ran perfect in this car I have manually copied just about every table (in Edit) (timing tables, VE tables, etc) to the 99 PCM. Still have the surge. I put the 2001 computer back in again and it idles perfectly. There are just not enough tables in the 99 PCM. A buddy of mine works at a dealer and said he could flash the 99 PCM to a 01 PCM as long as I have the VIN number of a 2001.

again thanks for all of the replies.

 

I thought for the longest time that they where 1meg like the rest until i kept sending out the wrong pcms to customers for them. opps.

 

the hardware itself is identical between 99 and 02 fbodies... the OS itself is diffrent.

you can flash a 99/00 PCM to have the same OS as a 01/02... and the reverse is true too, if for some reason you wanted to go back...

 

Back to the top. Why are there 2 different computer sizes (512kb,1024kb)?

 

More and more emmissions and stricter tollerences made it so they ran out of room in the 512k, The only option was for them to make the Flash hold more. every couple of years the size has gone up. Some computers use 2, 4 and even 6 megs out there.

 

Several Corvette forums reported the early and mid 2003 Corvettes had the 512k PCM's and the later ones had the 1024K PCM, it was a running change in preparation for the 2004 C5.