Hey guys ,
let me narrate the problem the way i am facing it , i run my car mostly on cng , just when i park my car in night i park it on petrol , so basically i shut and start on petrol , now recently i face this problem that when i covert my car from cng to petrol in order to park it , the rpm feels high which is normal as it converts from cng to petrol , but when i try to shut it , it wont shut , it starts jerking , so i turn the ignition other way round and it starts again as if it never shuts off , so i waited and done that few times but every time i wasnt able to turn my car shuts off , after few tries it eventually shuts off , now i have noticed that it only happens when i had my ac on and i switched it off few minutes before i convert it on petrol from cng , now i have checked the mixture setting , the plugs comes out brown so it all seems good , now the car timing is set as advance because i mainly run my car on cng , so according to my observation timing is it too advance ? and question is what is cultus correct timing setting to get maximum economical result on cng and no knocking on petrol ? my fella pw colleage babar reckon its some thing to do with ac vacuum pipe coming from carburator as i had recently ac service done , so all opinions are welcome , just need to get the base of this problem , car is giving good average on cng , i had no trouble running it on cng or petrol , yes it does knock a bit on petrol but i dont drive a lot on petrol so its avoidable .
regards.