stacking tuners.. and.. such...

[drewactual]

let's say I have a tuned truck, by brand 'x'.. let's say I don't have the ability to remove and unlock a tuner, because it has gone AWOL.. let's say I procure a new tuner from brand 'y', and commence tuning the truck.. what will happen?

Will tuner Y store the tune from tuner X as the 'stock' tune?

concerns I have;

- tuner X only alters, say, 5 tables on the PCM- and therefor only stores those five tables in the 'stock' tune retained on the device...

- tuner Y alters a total of 10 tables, and therefor stores only those ten tables as 'stock' tune..

or...

does a tuner take a snapshot of an entire PCM when it flashes? Maybe better asked, what tuners take a complete snapshot of a PCM when 'storing stock tune'? Which don't?

I've been researching this all over the place.. I've stacked plenty of tuners in the past (not on a diesel, though, and not that I 'want' to stack a tune)... the reason I ask this question:

I have an extra tuner.. I'd love to load it with what it thinks is a 'stock' tune, but what actually is a H&S tune- and for one purpose only- recovery if I lose a PCM or a PCM's contents for any reason.. I'd have a fall back position w/o having to perform surgery just to get it to operate again...

thoughts?

[dhanna6powerstroke]

I'll say it won't work because there is no stock file. Probably have to take truck to Ford and have the ECM reflashed to stock first.

[drewactual]

I'm 99% certain that superchips has a file that disallows a tune to 'stack'.. It won't allow you to re-write a table unless the stock file is unaltered..

I will agree with you to the same 99% certainty because of that..

I can't find anything conclusive about 'other' tuners, though.. this is what I DO know (or, at least with 90% certainty)-

all brands/methods of tuners communicate with the PCM with the same write/rewrite instructions.. there is only one way to do that.. the information they provide the PCM with is the same language/script, as that is set by FoMoCo parameters.. The tables of data they replace, though, is different- some alter this table, others alter another.. some alter how data from sensors are interpreted and stored, others alter how it is translated to other functions..

with the SCT tuners I've used in the past for gassers, the SCT didn't verify the 'unaltered' file to check for stock integrity before it started writing away.. it stored a literal image of whatever was there.. this allowed a person to load up a superchips tune, and then stack an SCT tune on top.. the SCT would retain a 'stock' tune that embedded the SuperChips tune.. you could not do this in the reverse order, though, because the superchips verified that one file for authenticity before it would allow you to tune..

If I could just obtain an image of the PCM in it's current and complete state, I wouldn't be looking for a way to back-door this thing.. Our off-road tunes aren't going to be available forever, is my reckoning- or, they won't be around as long as I intend to keep this truck..

[05_PSD_Erik]

H&S tuners have stock files preloaded on them. If your new tuner were an H&S, you can tune it back to a stock file with the H&S then load what ever H&S tune you want...
Also, the way tuning works with a Ford ECM makes stacking practically impossible. You load tune A which overwrites the stock file, then attempt to stack tune B onto the ECm it erases Tune A and now you are runing tune B