How to pass the Emissions Test
Those of us with the Rover engine are all still having problems passing the MOT Emissions tests, although I think most of us have the limits written on the V5 so we will not be affected by the latest changes that have been introduced. I have found a proecedure that gets me through every time. Just do the following:
1. If you have the original silencer, plug up one of the outlets. As I understand it, because the exhaust system was never designed for the Rover engine it doesn't provide enough back pressure to work properly. So by limiting the output you provide a more balanced system.
2. Run some injector cleaner through the system on the fuel fill up before the MOT.
3. Run MEMSAnalyser before the MOT to make sure your lambda sensor is working, otherwise you will never get through.
4. If you still have the original sensor I would recommend changing it for a decent one. The NGK NTK Oxygen O2 Lambda Sensor OZA527-E9 OZA527E9 (Available on Amazon) is the one we use.
5. Make sure the signal wire from the sensor to the connection by the alternator uses shielded cable.
6. Finally give the engine a real thrashing en-route to the MOT test so it is good and hot. When they actually do the test empasise to them that the engine MUST be at working temerature and to give it plenty of time to stabilise (on my test they saw the readings improving over about 5 mins).