Write / Re-Write entire PCM

[devildog9999]

I have been wondering for a while when to use which option. I read the help file, but it is not clear to me which instance to use.

If I make changes to several tables, say IFR and timing - can I just use the "write VCM" option, or do I need to use the "Rewrite Entire VCM"?

[horist]

just use the write VCM option...

Only time you'd need to write the entire VCM is if you're changing Operating systems

[SSpdDmon]

Is that what the hand-held tuners do? I thought I read something about HPT only taking 40 seconds, but with my Predator it took 2 1/2 minutes. Do the hand-helds re-write the entire VCM or are they just slow?

[devildog9999]

just use the write VCM option...

Only time you'd need to write the entire VCM is if you're changing Operating systems

Thanks, That is what I thought, but it seems like when I do thet the settings don't overwrite... I will try it today and then do a read and make sure it is something I am not messing up.

Gary

[RWTD]

Is that what the hand-held tuners do? I thought I read something about HPT only taking 40 seconds, but with my Predator it took 2 1/2 minutes. Do the hand-helds re-write the entire VCM or are they just slow?

That depends, actually. The Predator is not slow, and it is the fastest handheld on the market. It can write as quickly as the pcm allows. The U7198 Predator (99-02 cars/trucks, and 99-03 Vettes) writes the entire pcm, and the U7195 Predator (2003 trucks), and U7193 Predator (2004-2005 LS1 based cars/trucks) can either rewrite the entire pcm, or they can just write the tuning only file (takes approx. 30 seconds). It all depends on which file you actually upload to the Predator, the full file, or the tuning only file. The U7198 will be getting an update in the near future that will allow it to be inline with the other two just previously mentioned.

When not rewriting the entire pcm, make sure you reset your fuel trims after programming.

James - RWTD
- HP Tuner
- DiabloSport ChipMaster Revolution Tuner