Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) MOT

Small update

I have just returned from technical control and unfortunately I have a red card because of exceeding the lambda values. So I have to go back within 15 days but it will be impossible because the Albert garage

will close until September 29. Really this is the last thing I could have thought with the plus four .

Sorry to hear that.

This may or may not be of help

An issue I'm very aware of with both modern petrol and diesel Mercedes, in that if they have been used on short journeys for quite a while and have not been getting really hot then taken on a longer journey, the NOX sensor doesn't like it and the engine management light comes on and emissions rise, bad news at annual testing time.

I presume there are no error codes? Have you tried engine and exhaust cleaners and a fast Italian service run to get everything sinking hot and values down.

All I can add, is that my Roadster has a marginal lambda when using a K&N filter, which is well within limits on a standard filter. So my experience suggests that a slight variation in the inlet tract can affect the lambda.

It is a three hours drive from Garage Albert to the dealer in Utrecht. They should be able to fix your car.

Harald

Forgive my stupid question, but has anybody tested the effect of removing the air filter to test how that might affect the exhaust emissions on a cat equipped machine..?

very sensible question, I would like to know too!

Just a thought.. Is the Plus Four filter and intake located in a smilar position to the Plus Six?.. The Plus Six intake is low down on the right hand side front wing. I have found that if the car is used in wet and mucky conditions ( Somerset lanes ) the lower 3rd of the filter can quickly become clogged. I have changed 3 filter elements in the last 18 months as compressed air could not clear it all out even when dry. I have also water proofed the underwing lower hatch plate that is removed to enable the filter element to slide out..

My +4 passed with a K&N filter but it might be a lot of crud on the filter. It is low down on the car & my experience is straw etc builds up. You need to remove the plate on the underside of the wing behind the UK drivers side front wheel to clean it. In the photo of the car at Malvern you can see where the filter sits. Not ideal to my mind. the air come in via those triangular opening in the inner wing sucking in spray etc from the front wheel.

This is a construction error. Why not take in air from the front of the car?

Harald

I had the same issue with my Plus Four MY22 I posted on another thread. The car went to the MOT cold essentially. It failed. Re-booked the MOT and drove in a lively manner for 45 minutes for the new test. It passed with no problems. I was told by my dealer that the car needs to be properly warmed up and indeed, if it's not done many journeys, then a good blast to clear it out.


Worked for me but I understand your frustration. I had to wait 2 weeks to re-book my MOT.