Q: Washed Engine Now Car Won't Start

Washing an engine is a risky business. If you’re going to have it done, it’s best performed by a technician who will know where NOT to direct the spray. Now that it has been done, you could have a failure in one or in multiple components. First, you might need to get your old ECU back. Most of those ECU’s are coded so that they will only work in the car in which they were originally installed. They can only be unlocked and reprogrammed using the Jaguar proprietary diagnostic equipment. From there I would check t see that all the ignition coils are dry and be sure there is no water in the spark plug wells. Then look at all the electrical harness connectors to see if any of them are full of water or even if they were knocked off by the water jet. As for the car possibly running overrich: the injection time is controlled by the ECU, depending on signals from the Mass Air Flow Meter, the Accelerator Sensor, and the Temperature Sensors. faults in any of those can give you an overrich condition. I can’t recommend running out and buying those parts, they are expensive and may not solve your problem. This car needs to be diagnosed by a qualified technician. contact Your Mechanic to see if there is a technician in your area. If so they can come to your home and diagnose your No Start Condition and let you know what can be done about it.