5.3 to 4.8 swap

[pbmike]

I am new here, and this is my first post. I have a 2007 Suburban (200K miles) with a 5.3 & AFM. The engine is shot, no oil pressure. I have been having a tough time finding a running 5.3 AFM engine (2007 +) that I can swap in. I really don;t want to rebuild the current engine, as it will cost more than I went to spend on the truck at this time. I found a running 2007 4.6 for $700. Will this engine be a good swap. I don;t tow anything and don;t need alot of power. The 4.8 is a non-AFM engine. Will I need the ECM or ECU from the 4.8 to swap out, or will the 5.3 one work ok? Thanks in advance.

 

Mike

[CamGTP]

What generation truck did the 4.8 come from?

 

It must be a GEN 4 engine for it to swap in and match up to all your sensors.

 

You could not use the 4.8 computer, the suburban never came with that engine and it would never talk with all the computers in that truck. You will have to get an aftermarket tune on the factory computer. This would have to be done before you even started the truck because it won't run or if it did it would be running horribly because things haven't been disabled and changed for the smaller engine.

 

It will be less of a headache to find a 5.3 engine with AFM to swap back in. If that means buying one online or driving several hundred miles to find one that could be what it takes.

[pbmike]

I found both a 2007 and 2008 engine. Neither has AFM, but I think everything else would hook up the same (knock sensors, etc.) Why wouldn't it run with the 5.3 ECU hooked to it? What if i got one of the AFM disablers and plugged it in?

 

I did find a 2007 engine out of a GMC van, would this have AFM?

[CamGTP]

The AFM disable device does not turn off the circuit codes that also need to be disabled. If those are left on it will shut off those cylinders in the computer and not run.

 

The whole calibration between a 5.3 and 4.8 is different. Less displacement needs less fuel at any given time. The timing tables, airflow model and tons more all have to be changed. I've owned an aftermarket tuner for many years now, been down this road many times before.

 

Anything 2007 is a toss up. You need to get the engine code to see what it is or know the differences between the blocks/sensors. If the knock sensors are bolted to the side of the engine block and the cam sensor is bolted to the front timing cover, that is the correct GEN 4 engine generation needed for 2007.5+ vehicles.

[pbmike]

What if I used an ECU from the truck the 4.8 came out of (2007-2008)? Would that work?

[CamGTP]

Quote

You could not use the 4.8 computer, the suburban never came with that engine and it would never talk with all the computers in that truck.

I said this above already.

 

The other computer wouldn't work. They aren't the same vehicles and the can-bus system wouldn't talk with each other correctly. A custom tune from someone or a shop is required. Or just find a 5.3 with AFM.