Hi Everyone - This is my initial post, and I hope someone can help.
I bought a used 2011 cooper base (auto) in a non-running condition. Turned out it had a burned exhaust valve, so I bought a new set and fitted them. The head and block were in exceptional condition and all I had to do was lap in the new valves, and refit the head with new gasket and bolt set. I now have great compression on all cylinders, The engine started up right away. The engine starts, idles well and accelerates well - but ONLY with the MAF plug disconnected. As soon as I plug in the MAF, the engine dies.

I have changed out the plugs, coils, injectors, throttle body, MAP sensor and O2 sensor, all with OEM parts. I have now purchased two Bosch MAFs and each one results in the same failure.

The engine starts and runs perfectly with the MAF disconnected, so I find it hard to believe the ECU is faulty, but that's about the only thing I can think of. I did unravel the harness and check the wiring back to the ECU and couldn't find any issues there.

I should add that the ONLY code I get is "MAF disconnected" ...which it is! If I try to start the engine with the MAF connected, it starts and then stalls after about 3 seconds. This is not long enough for the ECU to generate any fault codes.

Help!

ReigateMate