Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Engine misfire and management fault

Found difficultly in running engine from cold and smelt petrol, when warm the amber engine management warning light came on at more than 2,000RPM
Dealership said I should not drive it so arranged for AA to come over and they said that both cylinders were firing but one not fully igniting, hence the petrol smell. They then put it on a recovery vehicle to the dealership. They have since reported that the diagnostics state "no fault" so are mystified
Has anyone else had this problem?
My M3W dates from December 2012 with just over 1,000 on the clock

Hi Philip
Sounds like it may be a failing ECU.
The exhaust would be wet and sooty.
An auto electrician found mine to be delivering 4 jets of petrol per rev instead of one, when engine cold but only at low revs ie <1000. When warm and revs above 1000 it was somewhat normal. Needed oscilloscope to diagnose this
Gradually deteriorated until car undriveable hot or cold
Replacement ECU was the answer.
Diagnostics did not show any fault. As the deterioration was gradual took month or two to reach this conclusion !

Hi

Thanks so much for your response and I have passed this onto the dealership

It is amazing to think that the answer could have come from 12,000 miles away!

Best regards


Philip

Hi Phillip, I have recently noticed a misfire between 5000 & 6000 rpm. I thought at first it was a rev limiter cutting in but it is defiantly a misfire.

Because it is so far up the rev range it is not too much of a problem as I hardly ever go above 5000 rpm and all appears well below this.

Something to go on the list for the next service in September i suppose, unless it gets worse of course.

It could need the latest Mapping?this is a very easy and quick fix:))

Thanks for all your responses and suggestions, I had a call from the dealership today and they believe that they have found the cause.....the timing belt has slipped a cog causing the petrol/air mixture not to ignite completely. The cylinders are only firing on every other revolution.

The solution is to fit a new belt and then adjust the timing accordingly

This is evidently a new problem to both Morgan and the dealership and I will keep you all updated as to progress

Thanks again

Philip

The way 4-cycle motors work is that each cylinder only fires every other revolution. A 2-cycle motor fires every revolution.

I can see the timing belt jumping a tooth, maybe. But if they jump they have to be loose and jumping just one toothe against the cam valve spring load and keep running is not too common.

I wish you the best of luck on your repair.

Good to hear that the issue has been identified and is being fixed.

It's just as well it's a "non-interference" engine!