Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 4.4 1.6 Sigma - odd noise/behaviour - Help!

Good day All,

A bit of an odd one. I took the Morgan out yesterday for a short drive and all was well until I was about 2 miles home. The engine felt like it wasn't to stall and whilst stopped at the traffic lights it sounded a tad lumpy and then would smooth itself out and idle normally. The next lights it did this again but this time I swore I heard some rattling coming from the engine and for a second thought the engine was done for. Got it home and all was fine.

I took it out again today for a quick trip into town and the same thing happened, lumpy idle from time to time and once in the garage I again heard the noise from the engine bay. I only just managed to lift the bonnet and it would appear it was coming from the cylinder head. No sooner than I could switch it off the noise went away. I started the engine up again, smooth idle followed by a few hiccups and a slight sputter but nothing drastic. I gradually revved it up to 5000rpm and gradually down, all smooth but again, at idle, lumpy/sputter from time to time.

It's a 16 plate with 19,000 miles and serviced annually by a mains retailer. Spark plugs and leads were changed at 13,000 miles.

I would take it to my retailer but they are in Bristol and I am located in Chester so not exactly around the corner.

Anything I can be checking myself? Does this sound like something major that I should worry about?

Thank you,

Perry

I had this with the 4/4 Sport Competition- hot weather and elecrobics?
Responded to hard driving!

Might be stale petrol, might be the badly installed roll over valve on the petrol tank vent. I’d suggest an Italian tune up😁

Well, it can have many causes. Since it comes and goes, I don't think it's a permanent mechanical damage (by the way, do you still have the first timing belt? then I would change it soon despite the low mileage of the engine).
So I would assume an electronic fault or a loose contact of all the electrical plugs or cables, starting with the MAF sensor plug. Do you have an OBD2 reader? That helps because some errors are stored directly. Unfortunately not all. As you describe it maybe a malfunction of the hydraulic timing of the camshafts? I had with my Sigma 1.6 4/4 a problem with the contact of an injector, that also led to the rough engine running. It was directly visible in the OBD2, even which of the 4 injectors it was.

Could well be

Thank you all for taking the time to provide some hints and places to look. All very much appreciated.,

@Ewan, whilst I don't drive it much, it has had a few full tanks of fuel this year and I do make a point of winding out the engine from time to time. My normal driving of the Morgan is by far not just bumbling down B roads

@Heinz, thanks for the input I'll get myself a reader and poke around on the electrics to see if I can spot something amiss. Now that I think about it, I went over a rail crossing, known to me, a bit faster than I normally do and it was after this that things went south so perhaps something did come loose! Might pull the plugs as well to see if anything is amiss there. As for the timing belt change, it's going to get done early next year when I go for service.

@Sprinty, it was a coolish evening both times out and I was not hard on the car at all.

thanks again all.
P