Thanks a lot for your reply ! In fact, I do no hesitate to spent when it comes to car maintenance. So I visited Toyota and even they had the Chinese Fuel Pump, which I did not given preference.
I think you are right to check the wiring, and I am sure you mean the wiring with the PLUG that plugs with the filter's top just under the back seat of the car. Am I right ?
I will check that.
Also, I observed that, i m not the only person facing this trouble, with me, I found 4 other people (1 vitz, 1 santro, 1 cultus and 1 i dont remember) and they all was buying a fuel pump.
I analyzed, and found something that can be TRUE. Here it is:
When we install CNG and when the car is ON and RUNNING on CNG, what the fuel pump is doing ?
The answer is that the fuel pump runs continuously. Now, the main function of the fuel pump is to THROW petrol to engine with pressure. But as we have CNG, the petrol is not injected to the engine, and fuel pump continues to put pressure.
This excessive pressure which is not really released anyway (as the PETROL is not going to engine) makes the pump tired and it started to deteriorate gradually and come to a point where it stops working.
Today, with my electrician, we did a new (or may be tried) experiment. We put a small button (not clearly visible though) and linked the fuel pump wires to that. Now, after starting the car, and converting to the CNG, the button will be pressed to stop the fuel pump. This way, the fuel pump will no more do any excessive efforts to boost petrol in to the engine. If we want to drive the car on petrol, we can simply press the button and then can convert to petrol.
What do you think ?
All other peoples, please put your thoughts on it.