Ls4 cam timing cmp relocation

[Ltcbm]

I just installed a ls4 in a project I'm working on. Using the 09 Impala ss e67. I put a ls3 cam and gear in it along with a ls3 timing cover. My question is: the cam position sensor on the ls4 cover is located in a different position ( about 90 - 120 degrees ) then it is in the ls3 cover. Should I not have to adjust the cam timing to make up for this offset? When I try to crank it it just back fired through exhaust. Injectors are pulsing and coils are firing. I changed operating system to a 08 tbss e67 and it fired right up. Nothing else is communicating with ect now and some composted not working but it let me know that it is a issue in the ecm. Gonna flash it back to ls4 is and try to figure out what is going on. Any help would be appreciated

[joecar]

Do you have any pics of the LS3 and LS4 cam sprockets to compare...?

[Ltcbm]

I didn't save the ls4 cam gear since it was vvt. I made the assumption that they were the same. But you know what they say about assuming

[Ltcbm]

Is a tech2 the only way to flash a ctsv ls2 os on it? Efi live will not because os not compatible.

[joecar]

The LS2 might not be compatible with it, even with Tech2.

[Ltcbm]

I'm gonna hook a snap on pass thru pro2 to it tonite and see if it will flash. Worst case is I'll brick the ecm. But if it don't work I'll have to get a ctsv ecu anyway. Just have already bought credits for it for efi live and hptuners trying to get this figured out. Have to buy more if I get a new ecu.

[ScarabEpic22]

Be careful swapping OS' on Gen IV+ ECMs, it can easily brick them if the underlying OS cant run it. You'll likely need to use a Tech II to change the OS, and SPS will NOT warn you about programming an incompatible OS (in most cases).

[Ltcbm]

I swapped the os with pass thru using sps. It did crank and run.having trouble with idle but that I can work thru. Still don't know the why but it runs now though

[ScarabEpic22]

I swapped the os with pass thru using sps. It did crank and run.having trouble with idle but that I can work thru. Still don't know the why but it runs now though

Just because you programmed it, doesnt mean it's going to work properly now...You cant switch the base OS platform on Gen IV+ ECMs very easily, if you pick one that isnt compatible with the previously flashed OS, you're more than likely going to brick the ECM. Or it will appear to work fine and have weird issues show up down the road, ask me how I know.

[Ltcbm]

I hope that's not the case with this one. I have not yet got it to link to the bcm for everything to work yet. I have the vin from the car in the ecm. I have tried using gm's sps and efilive both to link them and have not had any success.