I think the automobile engine example has to be refined to be more easily understandable. For example, be clear about what the electronic timing control is controlling when there's a carburetor, and describe how its function extends later to fuel flow.
For a long time cars had carburetors *and* distributors, if that helps.
I wasn't sure how your analogy represented IC but it looked promising and I thought more detail might make it clear, but the additional detail still doesn't help.
In the earlier internal combustion engines the removal of the carburetor or distributor would have rendered the engine inoperable. The later refinements of fuel injection and electronic spark distribution have the same quality - remove them and the engine becomes inoperable. The combination of spark distribution and fuel injection into a single module that if removed makes the engine inoperable is just more of the same. The IC was there from beginning (in the sense that creationists intend it, not in any real way), and I don't see any step-wise change from which IC emerges from non-IC.