A closer examination of these values shows that the 7947 defines which injectors are on the right side of the engine while location 7948 defines the left side.

The each channel represents a 16 bit number, and since a single EMAS II injector module only handles 12 injectors, only the first 12 bits are used.

Each bit represents a cylinder starting with cylinder 1 at position bit 0.

These locations define which cylinders are considered to be on the left or right side of the engine. The information is encoded into a 16 bit number in the following manner.

In the above example location 7947 is a 15 which defines injectors 1-4 as a right side injector while location 7948 is a 240 which defines 5-8 as left side injectors.

The obvious question is how did I come up with 15 and 240. The quick way for figuring that out is to use the scientific calculator available on PC's windows set it to binary mode, punch in 1111 then hit DEC and the answer is 15.

The same it true if you switch back to BIN and hit 11110000 then DEC, the answer will be 240.

For those computer types, the bit represent powers of 2, so 1111 is:

1*2^0 + 1*2^1 + 1*2^2 + 1*2^3 =

1+2+4+8=15

Some common settings for Ford engines are:

8 cylinder = 15 and 240

6 cylinder = 7 and 56

4 cylinder = 3 and 12

GM setting are different :

8 cylinder = 170 and 85 for example. (2,4,6,8 and 1,3,5,7)