2.2L engine swap

[iroc-s-10]

Hey i was wondering if anyone out there would beable to lend me some useful information.

I have a 1997 S-10 with a 2.2. in, my motor went on tuesday afternoon with around 320,000 kms on it, i drove out to ottawa yesterday and picked up a replacement 2.2 from a wrecker with a 110,000km on it. i came to find out today while i was pulling my old motor that the replacement engine is from a 1994 Sonoma, i was told by chevrolet and an area wrecker that this motor will not work in my truck because there is no knock sensor in the block on this motor, is this true? will dropping this motor in my truck be a waste of time? I'd really appreciate any information anyone out there has to offer!
If this is true would anyone happen to know a motor that would be interchangeable with my truck?
thank you in advance!

Dan