LBZ Full Flash - Need Reassurance

[VegasDMAX]

Hi Everyone -

The short version of my story is that my dealer reflashed my truck to OS 12632483 and I want to flash it back to the original, OS 12606128. Doing a full flash seems like a scary proposition to me and I'd like to ask a few questions before I try it.

The .tun I file I have for OS 6128 was extracted using EFILive version 7.4.2 Build 657. I have now upgraded my EFILive to 7.5.5 Build 81 and my flashscan unit to bootblock 2.06.02 and firmware 2.06.06. I have opened the old .tun file with version 7.5.5 and saved it under a different name, per the sticky post by Ross. So it seems theoretically at least, I'm ready to do a full reflash. Is there anything else I need to worry about? Is the general procedure for a full flash the same as a parameter flash i.e., hook up the flashscan the same, turn the ignition on, start the tune tool? After the flash is done, will I have to do anything else, like an injector recalibration for example? Has anyone here done a full flash on an LBZ and encountered any difficulties?

I've had my EFILive for sometime but I haven't done much with it so I'm very much a newbie. Thanks for your help..

Ed Allen

[ScarabEpic22]

Ed I cant help you full flashing a Dmax but any particular reason you want to flash back to the old OS? Why not just make a script to get the changes from your old tune and then run it on the new OS so you get the best of both worlds?

[VegasDMAX]

Ed I cant help you full flashing a Dmax but any particular reason you want to flash back to the old OS? Why not just make a script to get the changes from your old tune and then run it on the new OS so you get the best of both worlds?

The only "tune" I had done at this point was to shut off my EGR. I want to go back to the old OS, at least for now, because just comparing the two, stock for stock, my highway fuel mileage went down about 2 mpg. The only plus I can see for the new OS is that it doesn't smoke as much when I stomp on it.

[ScarabEpic22]

I see, have you turned the EGR off on the new OS to see if the mileage is back? Just asking, you probably have if you're ready to flash back to the old OS.

[VegasDMAX]

I see, have you turned the EGR off on the new OS to see if the mileage is back? Just asking, you probably have if you're ready to flash back to the old OS.

The EGR has been blocked since forever, and the finger stick stopped any codes until the EGR motor failed. That is when I shut off the EGR with EFILive. I put the stock parameters back in it (i.e., turned the EGR back on) to take it to the dealer for a brake booster leak. While they had it, the check engine light came on. So in troubleshooting the EGR they flashed the truck according to some GM bulletin. That's how all this happened. I'm sure the loss in mileage is totally related to the new OS, not to the EGR.

[ScarabEpic22]

So you're saying that you have not yet turned the EGR off in the new OS, just the old one? I might try turning it off first and then seiing if your mileage comes back.

[GMPX]

There is an easier option.
If you have your original stock tune then compare it to the last tune you have before the dealer upgraded the OS, you can actually create a script that you can then apply to the new OS, basically it will modify all the same tables / parameters in the new OS as per the old OS.
It just saves you needing to do the full reflash, because when you do change OS's the ECM can 'sometimes' decide that the injector flow rates need to be programmed and the remote start stops working. All can be fixed with EFILive but it's just a pain. Then of course next time you go to the dealer the same thing will happen again when they see the old OS back in there.

Cheers,
Ross