hard 6.0 tuning question

knagel

weakest link finder
Jun 4, 2007
219
1
16
Central, Iowa
Warning: this is going to be a long one.....

OK,... so I was asked by a local shop to tune a 6.0 in an 06 1500 Gmax. They changed the cam and put a fixed geometry cam in. All they wanted me to do was turn off active fuel management and shut off the cam phasers and change the tires size so the speed was correct. Simple enough. Succeeded in the fuel management and phasers but the speed would not correct. Customer took the truck because he needed it and was going to bring it back at some point to get the speed set. This was over a year ago and has been running fine.

Now the hard part.

Customer dropped truck off at their shop and I went over to work with the tire size. Nothing seemed to work no matter how or what I changed. Then all of a sudden the ECM fried. We assumed it was because of all the flashing I was doing to try to change the tire size. I would flash, driver for 4 miles, adjust, flash, repeat. I think I did this 3-4 times then the ECM fried.

We got a couple junk yard ECMs as they are cheap and easy to come by as all 4-6-8 cyl gas use the same ECM in those years. Full flashed the ECM and It would run the engine but go in to reduced power at 71% throttle. Then it eventually fried. We used the 2nd ECM and decided to flash the owners trucks program in to the ECM as it was an 06 6.0 with out active full management and no cam phasers already from the factory. This program ran the truck but still went in to reduced power at 71% throttle.

All other BCMs, TCMs wiring harness were checked out and were good, even though codes were set that pointed to a bad BCM.

I kinda threw my hands up and said that he needed to get a known good ECM from the dealer with the correct program for this truck and then we could start over again.

Mechanic used a used ECM again, downloaded the program off the GM website and installed using his techII. Truck has been running fine ever since and owner is able to adjust speedo with a superchips programmer along with changing tunes with the superchips.

Question is why did this all happen with EFI live? Was I working with a corrupt file from the start? Did EFI live not full flash a complete program? Why would EFI live not be able to adjust the speedo?

Just wondering, the owner has his truck now and all is good other than I blew 3 licenses going through fried computers to finally throw my hands up. This should have been a straight forward change 2 parameters and the speed and be done job.

Kevin
 

turbo_bu

Member
Mar 27, 2007
191
6
18
Central IL
Not sure if this is the problem or not, but I have read that if you mess up the speedo correction, that it can results in a dead PCM. I "thought" it was just if you entered in zero for the # of pulses per mile, but there might just be a minimum / maximum that if you exceed it, it will also result in a fried PCM.
 

knagel

weakest link finder
Jun 4, 2007
219
1
16
Central, Iowa
This fried even with the factory calibrations.

I was almost like EFIlive missed something when either taking the original tune out or putting it back in and it threw stuff out of whack so bad that it either fried the ECM or made it so the tune was incorrect some how?
 

knagel

weakest link finder
Jun 4, 2007
219
1
16
Central, Iowa
nope, not yet. thought I would see if there were any guys on here that have messed with gas first.

that's my next step though

kevin
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,281
337
83
Central OH
Cal flash or full flash?

Haven't messed with gas tunes, but I've flashed dmax trucks countless times in one day and never fried one.