WI on Toyota 4.2 1hz diesel non turbo
 

Engine is in a landcruser. I have no intention of fitting a turbo and am only thinking of fitting the WI as a measure to de-carbon the head. The engine has approx 270000kms and runs fine. I've seen the cleaning effects of WI on petrol engines.
I was thinking a low dosage of water triggered by a throttle position switch so it only injects when throttle is open more than say 50%. Engine has no butterfly so a manifold pressure switch wont work.
Will a setup such as this give me the cleaning effect I'm looking for?