Swapping PCM's into Early 99?

[orion_134]

I have an early 99 250 and I hear that the tranny program sucked on these PCM's. I hate how it shifts (or that it doesn't sometimes) and I am curious if changing PCM's to a later model PCM will fix it? I know there are difference in intakes and whatnot, but will the computer function exactly the same? Is it worth it?
Jesse

 

[Tail_Gunner]

I have an early 99 250 and I hear that the tranny program sucked on these PCM's.

This is very true.

I hate how it shifts (or that it doesn't sometimes) and I am curious if changing PCM's to a later model PCM will fix it? I know there are difference in intakes and whatnot, but will the computer function exactly the same? Is it worth it? Jesse

Changing to a 99.5 & later PCM is one of the best mods that can be done for an early 99. Before, my truck wouldn't tow up a slight hill or into a headwind without dropping out of O/D and down to 3rd gear. I had most of the throttle left, but the tranny programing wouldn't let me use it without downshifting.

I got a PCM from DP-Tuner programed with his 80hp econo tune.

FWIW, here is a reprint from my first test drive with DP-Tuner's reflashed PCM:

Well, the DP Tuner fairy came in the little brown truck today, bearing a PCM flashed with a Econo/ 80 hp tune.

It took me about 10 minutes to swap PCM's. I get Jody's PCM installed and head for the highway. I turn onto the highway, apply light pressure to the "Go Pedal" and I instantly hear this horrendous sound of rubber being removed from the rear tires. So I let up on my right foot and try again. This time with even less pressure from my right foot.

I come to a stop sign, and think to myself "OK, lets see if this DP-Tuner guy is all he is cracked up to be." Well, I slowly roll through the intersection, and the right foot goes to the floor. "DDDDDAAAAAMMMMMNNNN!!!!!" I've been driving this truck for 5 1/2 years and it has NEVER moved like this, even with the old anemic Banks chip!! My arse gets pressed into the seat so hard, I think I killed what was left of the cushion. I look in the passenger side mirror & there is light to moderate smoke coming out the exhaust. Not bad, but enough to let folks know this is a truck to be reckoned with.

Boost: most I usually see with the Banks chip- 22, 24 on a good day. Observed boost with the DP-Tuner Econo PCM- 28 psi!!!! THIS TRUCK HAS NEVER SEEN THAT MUCH BOOST BEFORE!! And this wasn't even an optimal day either! On a better day weather wise, it would likely go higher than that. Keep in mind also, this is an early build 99 with a tiny, "stock-as-the-day-it-was-born" turbo!! I only went for a 10 mile or so test drive, so obviously mpg observations will have to wait.

Later on I was able to do some towing, and the difference was like night & day. Before where the truck wouldn't tow on anything but level stretches without dropping down a gear. Afterwards, it would almost pull up a verticle cliff before it would downshift. The difference was amazing. By far the most effective mod I have done.

 

[orion_134]

But do you think the improvements will be as noticeable behind the SCMT? I don't think the SCMT changes tranny logic...maybe someone knows? Do you think the program on that new PCM is what made the difference or the PCM itself?
Jesse

 

[Tail_Gunner]

But do you think the improvements will be as noticeable behind the SCMT? I don't think the SCMT changes tranny logic...maybe someone knows? Do you think the program on that new PCM is what made the difference or the PCM itself?
Jesse

The PCM itself is better for a 99.5. The computer chip is more powerful and allows for better programing.

A programer has to be compatable with the PCM. You can't take a programer with tuning meant to work with a "pentium" computer (99.5 trucks) and expect it to run good on an old "386" computer (early 99's).

 

[orion_134]

The SCMT is meant for 99-03 7.3, so I'm sure it will work. But, I'm just wondering if I will notice any difference (keeping the programmer on the same setting, etc) by just switching from 99-99.5. I'm afraid that your results are better because the DP tune is superior to the Banks tune. Did DP change any of your tranny settins with his tune?
Jesse

 

[Tail_Gunner]

The SCMT is meant for 99-03 7.3, so I'm sure it will work. But, I'm just wondering if I will notice any difference (keeping the programmer on the same setting, etc) by just switching from 99-99.5. I'm afraid that your results are better because the DP tune is superior to the Banks tune. Did DP change any of your tranny settins with his tune?
Jesse

You're missing the point. Banks Ottomind chips don't do anything for tranny programing. The tranny programing that the Banks chip utilized is that of the stock tuning, in my case, a XLE_ program.

By going to the 99.5 PCM with a PMT_ program, the tranny operation improves greatly. The PMT_ programs are a more advanced program allowing for better tuneability than what a XLE_ program is capable of. The PMT_ programs cannot run on an early 99 PCM, so trying to download a 99.5 tune to an early 99 PCM won't work. What you are trying to do is like attemping to take software written for a recently made laptop, and run it on a 20 year old desktop. IT WON"T WORK.

When DP-Tuner or any other tuning outfit makes a tune, they are using the factory tune and "tweaking" it to obtain the desired performance improvement. That includes refinements to both engine & tranny operation.
If you want the refined tranny operation of a PMT_ based program, you have to have a 99.5 PCM.

If you have a programer that is advertised for 99 - 03 7.3L engines, what it will do for early 99 trucks is load tuning for an early 99. It won't load a 99.5 programing onto that early 99 PCM.

 

[95_stroker]

If you have a programer that is advertised for 99 - 03 7.3L engines, what it will do for early 99 trucks is load tuning for an early 99. It won't load a 99.5 programing onto that early 99 PCM.

Correct, the programmer reads the VIN and determines which tune to load.

 

[orion_134]

So basically, the programmer potentially has a better tranny tune already in it that can be used when I put in the new 99.5 PCM? Will installing a new PCM mess up any other functions assuming both are cal'd for 4x4, auto, and 7.3? In other words...win win I need to get one?
Jesse

 

[Tail_Gunner]

So basically, the programmer potentially has a better tranny tune already in it that can be used when I put in the new 99.5 PCM?

That's right. But I don't know if an "empty" PCM will accept a program from a downloader. It might have to have a program installed initially on it. I think a lot of programers will remove the current program and save it, replacing it with the new program. That allows the original program to be reinstalled prior to getting work done at the stealership.

Will installing a new PCM mess up any other functions assuming both are cal'd for 4x4, auto, and 7.3? In other words...win win I need to get one?
Jesse

It won't screw anything up.

If it did, I would have found out by now since I've been running a 99.5 PCM in my early 99 for over two years now.

 

[orion_134]

It isn't empty, it's just a pull-off from a wrecked truck. I think I'm going to try to haggle the guy and get one from him.
Thanks,
Jesse