I usually write that performance of a car’s engine chiefly depends on the fuel supply. Injectors are electronically controlled fuel valves which deliver atomized petrol in the chamber for combustion. When solenoid of injector is energized by ECU, the plunger in the injector moves away from the tiny hole on the tip of injector and allows passage to the fuel. As the pulse discontinue, the plunger again closes the path of the fuel.
Every time we turn off our car's engine, last drop of petrol dries on the nozzle of the injector and leaves behind deposits. These deposits become firm with the heat of the chamber. The more we drive our car, more deposits accumulate. Gradually it starts to restrict the flow of petrol from the tiny hole on the nozzle and the injector starts to lose its efficiency. Only 8% to 10% of clogging is sufficient to make an injector inefficient which cause the engine to stumble and hesitate on different rpms, idling becomes rough, power and pickup is lost, the car becomes uneconomical on petrol, unburnt fuel can be noticed in the emission and worst of all the wear of engine becomes faster.
Qaswah, A Pakwheeler friend read the post on some other thread and asked three questions which were quite pertinent. I want to share those questions and their answers with readers of this thread as they relate to the very scope of this forum.
The questions were
1. If petrol flow is less due to sediments then why unburnt fuel from exhaust ?
What is the relation b/w clogged injectors and engine wear ?
If we are injecting less fuel (due to sediments) then why fuel average goes up ?
I am sure reading these questions would have aroused your curiosity too :D…So here are the answers:
1. If petrol flow is less due to sediments then why unburnt fuel from exhaust?
We all know that fuel injectors are electrical solenoids. The injector contains a pintle (valve) that closes off an orifice at the nozzle end. When electric current is supplied to the injector, the armature and plunger move a short distance against a spring, allowing fuel to flow out the orifice. Because the fuel is under high pressure, a fine spray is developed in the shape of a cone.
The spraying action atomizes the fuel, adding it to the air entering the combustion chamber. Now as you know that atomization of fuel and the spray pattern are two very important phenomenon of electronic fuel injection system. In some instances, deposits on the tips of the injectors can change the desired fuel spray pattern and affect the atomization, resultantly the fuel does not get atomized properly and takes longer to evaporate in the cylinder. This is how we get smell of unburnt fuel in the exhaust. Let’s summarize this whole phenomenon in few words. When the injectors are not clean they do not atomize or vaporize the fuel efficiently. Badly vaporized fuel takes longer to evaporate in the cylinder. In every next cycle more foully vaporized fuel enter the cylinder and generally cause drivability issues as well as bad emissions.
2. What is the relation b/w clogged injectors and engine wear?
As all of us know, that the crank shaft receive power from the cylinders through connecting rods which on their other ends are tied to the pistons. Pistons move due to the combustion and deliver the power to the crank shaft which is further conveyed to gear and the vehicle moves. Imagine a crankshaft which is receiving equal power from all the cylinders to which it is attached. Such shaft will move in a harmony and will perform on a synchronized optimum level. Now imagine another crankshaft which is receiving altogether different jolts from each cylinder it is attached to. Imagine cylinder 1 is pushing the piston with 5000 psi cylinder 2 with 3700 psi cylinder 3 again with 4700 psi and my goodness… the 4th is just producing 3150 psi….ouch…what a dissonance…Every one can imagine how such an engine will depreciate. This is what happens when the fuel injectors are not firing the symmetric amount of fuel. And symmetry is for sure disturbed when the injectors are clogged.
3. If we are injecting less fuel (due to sediments) then why fuel average goes up.
This one was simple for me to reply 
and I am sure most of the readers know the answer
When the injectors are clogged we don’t get desired response from the engine as its already leaning due to fuel starvation. To rev up, we push more on the accelerator and inject more fuel into the engine which go waste yet we don’t get enough power.
