6.2 to 5.3 swap questions

[Thatoneoldguy]

Here is the story of my mess...6.2 failed in my 2011 silverado. I had another gen 4 5.3, so I decided it's cheapest to just swap. I installed a sloppy stage 2 cam and headers and installed it. Here is my problem it won't stay running, it starts almost immediately but shuts directly off only rarely can you get it to take throttle. I disabled both vvt and dod and moved the idle up some but it does not seem to have helped. Am I wrong to assume I need to find a 5.3 base tune and do above changes? Also maybe way left field but would not having 02 sensors do this? I'm still waiting on harness extension. Any help is appreciated

[2xLS1]

I had another gen 4 5.3

With those kinds of details I'm someone will be along shortly to tell you exactly what the problem is.

[RDF1]

So your using the 6.2 tune with just a raised idle?

[blindsquirrel]

Is it bigger than a breadbox? (context)

Since every 6.2L is rectangle port and every 5.3L is cathedral, I'm guessing you changed the intake manifold? And which intake manifold is it, which p/n injectors does it have now (transfer over the 6.2 injectors or kept the 5.3's?), which MAP sensor (are both manifolds pre-'09, or both '09-up, with the same sensor?), and everything else that needs to be accounted for in the tune file (which you neglected to post, along with a log file showing 'it won't stay running, it starts almost immediately but shuts directly off only rarely can you get it to take throttle', by the way)?

[Thatoneoldguy]

Yes, I switched the intake to match with the motor, and it was an 08 truck intake (but I did install the newer 09+ map sensor) it is running the 5.3 injectors. I will look into how to post the tune file and logs.

[gtstorey]

Always give a part number for parts, not just a “year”.

[Thatoneoldguy]

Gotcha, I'll get part numbers when I get home

[blindsquirrel]

The early MAP sensor ('08-down) has the orange silicone 'Christmas tree' style seal, the late ('09-up) sensor has an o-ring. I don't think the 2011 sensor will fit the 2008 intake, the manifold is made different.

[Thatoneoldguy]

You are correct luckily you can use the correct size drill bit and make the ring fit very snugly (i do not think you would be able to make the 08 sensor fit in a 09+intake however). But your comment about the map is what helped me find the problem. In my hurry I forgot to torque the intake down. The bolts were only finger tight. I will probably comment later with the injector numbers and log file, but for now it starts and idles

[Thatoneoldguy]

12580681 is the injector number and this is the cam spec.
Specifications】- Valve Lift (1.7 Rockers)--Intake Valve Lift:.585", Exhaust Valve Lift:.585". RPM Range: 2200 to 5400, Lobe separation angle: 112?, Intake Centerline: 108?. Advertised Intake Duration283?, Advertised Exhaust Duration: 286?, Intake Duration @.050": Lift 228?, Exhaust Duration @ .050": Lift 230?

Waiting on a o2 sensor extension for the passenger side before I can get a log