I've been spending ALOT of time and effort getting this truck to run right in SD mode...and in the process I think I've fixed all of the "issues" people seem to have with the '99/'00 PCM's.

Here's the problems and what I've done to fix them:

This is using HPTuners (sorry EFILive and LS1Edit guys)

1. False Knock - The '99/'00 PCM's are famous for false knock, sometimes up to 8º at all times, the knock sensors are set WAY too sensitive from the factory and changing the settings to the ones used in later years doesn't seem to improve the problem. In order to get the knock sensors down to a reasonable sensitivity you need to do this: open Engine-->Spark Control-->Knock Sensors-->Knock Sensor Level vs. RPM vs. Cyl and set 0-1200rpm to 9.0, set 6400-8000rpm to 25 and then interpolate everything in between to get a nice smooth table...this will get you close and will be sensitive enough to catch REAL knock without seeing false-positives. I can run 26º at WOT with 130º IAT's and still get no knock (false OR real)

2. Idle Quality - Open Engine-->Idle-->Idle Airflow-->Idle Airflow and scale from 68º and up by 15%, thie will imporove things dramatically and again will get you pretty close to ideal (this is assuming no aftermarket cam...you'll be playing with this table alot more if you've got an aftermarket cam)

3. Harsh Shifts - This one is pretty easy, on early PCM's if you set the Desired Shift Time to less than 250ms the PCM freaks out and will shift ALOT harsher than it should, all of you that zereo'd out your Desired Shift Time should go balc in and set it to 250ms....that's 1/4 of a second.

More Later......

 

A lot of good info, but I have heard that it is bad to set the the Desired Shift Time to less than 250ms , and others say to set them at zero.
Doesn't this table have to do with the trans learning the shift speed?
Dewey?

 

I've heard mixed things about setting the shift speed below 250ms...but ALL say that on the '99/'00 PCM it's a BAD thing to do. This table tells the transmission how much time it should delay between shifting out of one gear and into the next...the longer the delay the smoother the shift as the trans has a chance to spin down between gears.....

 

I've been running w/ the shift speed zero'd out for a while now and its been working pretty good. From what I've read zeroing it out disables the Adaptive shifting where the pcm tries to learn and adjust. So far I have not been able to confirm this though. But it works for me.

 

Which makes sences, if you up the shift time and have Adaptive shifting learn and adjust for a softer shift.

 

Yep. It disables learning. For those of us with a shift kit, and have set the base pressure to stock settings, as recommended, if you do not disable adaptive shift learning, then it will not shift properly, as it will learn itself away from the stock pressures.

 

Don't forget that I'm talking about '99/'00 PCM's....this info is useless on anything 2001 and up

 

I just checked out a 2000 bin, I think the upgrade to the 01-02 ECM is worth it just for the "Genral pressure" tab!

 

How come? They both have the same table but they don't work the same.

 

different ECM O.S systems..... check out the Genral pressures tab on a 02 compaired to a 99-00