Okay, long story short, buddy bought the truck not running and deleted at an auction against my advise. He gets me to look at it because he can't get it running. I start nosing around and notice that the ECM is missing. And there's an H&S tuner under the seat, in it's foam lined box. So we order one brand new ECM, had another buddy from GM come over and put the stock programming and set the injector data, hurray, truck now runs. I plug the tuner in and it had been put to stock. Uh oh. So someone parked the truck, put it to stock and robbed the ECM. Sure enough we find out it needs head gaskets. So I get roped into that, and a year goes by with him happily on the tow tune. Then it breaks the crank. So we go through that, but I get him to buy an alternate fire camshaft to go along with the new crank to make it live longer. Moved the injector wires and moved the values in the ECU to match and it runs smooth. However buddy says it's down on power a bit and doesn't get the mileage it used to. So I'm going to have to tune this thing.
I know HPTuners is write only. I think I can put the truck to stock, edit and flash, then use the handheld H&S to lay the delete tuning back in over my modified file, as long as I don't select any power options. Is this correct?
I also know next to nothing about electronic diesel tuning, the only diesel tuning I've done was on the 12v cummins mechanical pumps. I'm trying to get my head around how a bigger camshaft influences a diesel and what changes I need to make to optimize this. He on occasion tows heavy, 15K+ straight up a mountain and likes to race other trucks towing as well.
So in summary, if my tuning strategy works, I'd like to at least get him back to the power and mpg levels he was at with the stock cam. I'd like to avoid timing changes if possible because I really don't want to put pistons in this thing next.
Thanks in advance.
2011 LML full delete, all stock except for:
Wagler stage 1 A/F camshaft
ARP head studs
H&S handheld tuner, 3 canned tunes "TOW" "STREET" "PERFORMANCE"