BMW 518ise touring (UK)

[steve p]

Help Required!

My 1995 518i is coverted to LPG. When the engine is cold (overnight), the engine starts perfectly and warms up on petrol before switching to gas. My problem is that until fully warm, the engine sounds like it is missing and on 3 cylinders until revved over 2500 rpm. I have had the fault codes read and it shows the Lambda sensor and knock sensor faults. I then explained the symptons to the garage and they suggested it may be the cylinder head gasket and then tryed to show me that there were CO2 readings in the top of the radiator. Unfortunately the readings showed zero. They kept it overnight and told me there were readings in the radiator. I am not convinced as there isn't a trace of water in the oil or oil in the water. The temparature remains constant at the correct level. A small tear in the rubber air hose has also been mended but this hasn't made a difference. Any ideas ??

Thanks. Steve Parker.

[Interceptor]

My 1995 518i is coverted to LPG. When the engine is cold (overnight), the engine starts perfectly and warms up on petrol before switching to gas. My problem is that until fully warm, the engine sounds like it is missing and on 3 cylinders until revved over 2500 rpm. I have had the fault codes read and it shows the Lambda sensor and knock sensor faults. I then explained the symptons to the garage and they suggested it may be the cylinder head gasket and then tryed to show me that there were CO2 readings in the top of the radiator. Unfortunately the readings showed zero. They kept it overnight and told me there were readings in the radiator. I am not convinced as there isn't a trace of water in the oil or oil in the water. The temparature remains constant at the correct level. A small tear in the rubber air hose has also been mended but this hasn't made a difference. Any ideas ??

Change your knock/O2 sensor and see what happens. You should also try changing the spark plugs, if that wasn't done recently. Also, inspect your engine for air-leaks, they can give you a lot of headaches.