Good day to all,

I'm having this very big problem with my lancer 93 model 4g15 engine after I've brought it to my local mechanic for overhaul due to sudden timing belt breakdown.
Normally my car consumes around 13-17km/L. After the overhaul, it suddenly consumes a very heavy amount of gasoline which is around 5-8km/L.. (thats a hell of money -_-)..

My mechanic demanded parts that needs to be checked and changed. We already change Serbo with replacement and tried 2 sets of surplus injectors but nothing has happened. Still it emits black smoke which is somewhat toxic when smelled and also consumes still heavy amount of gasoline. So my mechanic ask for a Brand new Injectors which is a Hell of a Cost again for me.

I'm asking for your help guys if you know or also have experienced the same problem with your car and got the best solution for it. I already changed many parts and spend a lot of money with this car so i really want to know what really is the exact problem why it consumes a hell of amount of fuel. Running condition is good and already ask few mechanics whether there is a problem or faulty procedures with the overhauling but they told me that the overhaul was good..

Also been to an electrician to check for the Electronics/Computer Box but the electrician started checking first the Injectors instead of the Electro box and instructed me that the injectors is spitting a hell of fuel and it was the one malfunctioning.. So i then get back to my mechanic and told him what the electrician told me but in the back of my mind, I was doubtful that it was the injectors that really is causing high consumption because we already have replaced it twice with surplus (yes i know that it was a surplus parts and there's a big probability that it is not already in good condition maybe?.. but because of the fact that i already changed it twice without any significant change in consumption between the 2 sets of injectors, makes me doubtful that it is really the injectors that was malfunctioning..

So really need your help guys.. what should i really do? change? or fix? please help.. thanks in advance