Yes ! Differance remarks on valve timing of multijet,DDiS & quadrajet is wriiten as per discussion with Drifter.I had discussed about effects of bad fuel. He replied & cleared my doubts about how adulterated fuel affects the performance.I can't write complete discussion here. But in short following is the theory.As per drifter replied following is my conclusion. Inlet charge of fuel should burn out completely before closing of exhaust valve. (Before entering new charge in combustion chamber)Adulterated fuel can't burn fastly. Combustion process becomes so lethargic that there is need more time to complete combustion process.. More time to complete combustion means to close exhaust valve lately. & to open inlet valve lately.If combustion is not completing at the time closing of exhaust valve. Then new induction charge comes in through inlet valve.Then new & old fuel charge are mixed & engine starts to knock. & that time when we rise the throttle, we get feeling of suffocation in combustion chamber & power loss. Abnormal negative pressure is created in crankcase.But in M Swift exhaust valve is closed lately. There is more time to complete combustion before opening inlet valve than Multijet That's why diesel with kerosene added does not affect so much performance in DDiS.P.S. :-As per my info , all parts are not same in DDiS. While manufacturing DDiD engine,MSIL has deleted 2 parts from original multijet engine.1. Oil cooler & 2. Knocking sensorAbout oil cooler I am sure coz this info I had got from FIAT officials.But I am not sure about deletion of knocking sensor. Is there anyone who can confirm this ?