Quote:
Originally Posted by Breadman
correct me if im wrong but you shouldnt get a code because the air is already metered
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There are many reasons it could throw a code if the air flow is suddenly changed.
Going from a 65mm diameter throttle body to a 76mm diameter (quite a large jump, in my opinion) is a ~37% increase in flow area (bore of the TB), which is huge.
That much increase in flow area is going to significantly change the pressure inside the manifold, which is measured by the MAP (manifold absolute pressure) sensor. It is also going to change air velocity. Not sure if velocity is directly measured by the computer, indirectly, or maybe not at all.
As air velocity changes, it will change how the air interacts with the incoming fuel - both the port injection and direct injection inside the cylinder.
I suspect port injection will not change much, but I do know that direct injection is heavily dependent on strong air velocity, creating a 'swirl' effect inside the cylinder.
Even if there were no official codes thrown, I would fully expect the car to 'run like shit' if handicapped with that huge of a throttle body.