The engine ECMs are coded to the truck body ECMs. I swapped motors on my '03 and had to use the original engine ECM that came with the truck. When I first installed the replacment motor I used the ECM that came with it. Truck would start then die after 2 seconds and I got a security code. Had to swap in the ECM from the original engine that I pulled out to get it to run.

Buying a used ECM a swapping it in my require a trip to the dealer to get it flashed to accept your truck.

 

I have gotten 1.5 mpg better mileage with one of their programs. I was just looking for more. My best to date is 19.98 mpg. I've heard so many folks say they can get 2-3 mpg more with the early 04 vs the 04.5 so I was just wondering if anybody had given it a shot. I figured at $685 for a standard Smarty against the cost of a used ECM and a flash might be good $ents if it would net 2-3 mpg. We all know how to get the power out of this engine but I'm looking for economy..........first.

 

The injectors are physically different as well I believe. I don't think the 3rd injection event is responsible for a big mpg loss. I would bet if you messed around with enough different combinations of pressure, timing, and duration you could probably find a tune setup that would net you the 1-3 that you are looking for. I would say it is not worth the potential damage caused by swapping the ecms like that. What about the features that are available on 04.5 and up. There are actually quite a few creature comfort features and options that are in the electronics.

Just my .02

 

The difference is 03/04 have 8 hole tips, 04.5+ have 5 hole tips, injector bodies are identical.

04.5+ have a narrower spray angle, allowing for more advance timing without spraying fuel outside the bowl of the piston. If the timing is so advanced, that it is "saturating" the crown of the piston, not only will it melt the piston(eventually), it will wash down the cylinder walls with un-burnt fuel, limiting lubrication. (unless you use 2-stoke oil).

This is one reason why programming for the 03/04 is critical(with stock injectors), you cannot run a program based on a 04.5+ max timing(TNT) on a 03/04 truck. You will spray fuel on the crown of your pistons and catastrophic failure will be the result.

03/04 owners, need to be aware of this. I have been a "lucky" offender, stacking with TST, EZ, etc.

Now start adding or subtracting injection events ? This is COOL!

 

Yes, but that was taking the 3rd event away from a 04.5+ ECM.. The motor doesn't care, but the ECM didn't like it...

As far as the injector tips and angles, the ECM doesn't care.. Its based on the injector and bowl being matched, which they will stay if you swap ECM's.

I would think you could swap and 04.5 and 05, but not an 06 as the wiring is VERY different.. .

Lets get a couple of buddies that are bored, one with an 04 and one with an 05... Then swap and see.. .It should just be the ECM on the block, and a couple of plugs...

 

I think you missed the point of my post.....

 

You can NOT use a 03/04 ecm in a 04.5/05 truck. It will not work

 

Thanks for raining on my parade Bob!!
Hah.