I have civic 2000 vti oriel bought in 2000 brand new from the showroom. The engine was swapped at 280,000 kms in 2015 but I was not involved. Now from one year I am driving this car. Now it has around 303,000 kms. It has cng installed (Landi Renzo). The main problem is the fuel economy on both petrol and cng. On petrol it is worse than you can think off. It does only 4.5 km per liter whereas this engine D15Z6 is an economical engine. The engine runs smooth. On cng it's only do 75 - 80 Kms per cylinder (55kg).
On petrol it doesn't give any cel in any situation. But on cng if I press full accelerator the car accelerates and then there is a jerk and then it gains speed normally and cel turns on. The cel code is 3 - MAP sensor,14 - iacv.
There is no O2 sensor installed on exhaust whereas the engine is from a european car. The ecu also does not match with the engine.
On petrol, the car runs smoothly accept if ac turns on and if I put more load, it does not maintain rpm.
3 - 4 days ago, a mechanic has done a very bad jaugar by connecting the iacv sensor wire to the condenser fan wire and in between he puts a bulb. Now when I turn on ac, it does maintain the rpm. He said that it should be done and without even opening throttle body he says, "Butterfly kati hoi hai, throttle body aur Iacv change kerni pary gi". I told him to open and clean both of them but he said that will not help.
The engine head is P2J-4 and on corner 95 is stamped.