Aoa dear Pakwheelers and experts,
Well there's a strange problem in Cultus 2006 which i am stuck nowadays and need expert opinions. Mine Cultus 2006 model has completed 106000 kms on odometer and radiator fan is automatic with Thermostat valve installed. Few days back, when CNG supply was banned here in Faisalabad, we converted to Petrol (though, we used to drive a day or two in a week on petrol when CNG was available) and did the necessary adjustments required by the car to run on petrol such as setting RPM, removing the air blockage. Thereafter converting to petrol, the car started giving black smoke and fuel consumption was severely disturbed. Also there were not any water vapors or water coming out in such a cold weather.
Being a silent Pakwheeler, I visit this website regularly and have gained a lot in understanding car engine's basic functionality. So I searched forums here pertaining to black smoke problems and came with following suggestions posted on other threads by experts:
---> stuck choke plate
---> Proper mixing and adjustment of air/fuel ratio
---> Carburetor service
---> Butterfly problem in venturi
---> Petrol fuel filter cleaning
---> Plugs service
---> Float level height in carb can be high
So I went to the mechanic yesterday and told him the problem and he said carburetor requires service as it has never ever been serviced since we bought the car in 2006. So he serviced the carburetor and changed the butterfly in carburetor. He adjusted mixture ratio and also checked choke and plugs. All fine according to him. He started the car, rev up the car and black smoke problem was still there with no water or vapours coming out. I asked him whether the float level in the carburetor was according to the desire level and whether jets within carburetor need further cleaning. He said no problem in float height and jet servicing. So right now I am puzzled what could be the problem. The car runs perfect MashAllah. Pick is awesome after carburetor service. If everything is fine according to mechanic and according to my understanding, then why car is giving black smoke throughout driving even when the engine is warm and why water or vapours are not present in such cold weather when ideally it should give vapours out.
Dear Pakwheeler and experts, I leave it to you. What could be the possible problem and what could be the remedies possible. Waiting for you replies.
The real culprits were bad air-to-fuel ratio and ignition timing. So adjusted the A/F ratio to correct settings and ignition timing set to 10 deg BTDC on petrol. Before, it was 15 deg BTDC for CNG purpose. Moreover, following things were also done:
- Carburetor service
- Replacement of carb butterfly with Qabli one
Spark Plug service
Now the car runs fine MashAllah and giving water droplets as well in the start. Thank you guys for your valuable inputs.