Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2010 4/4 sigma pinking

My apologies, I missed the 2010 bit and that we were into black box technology and so no longer able to sort things like this out with a simple twiddle.

I'll stay in my time warp

Steve

Thank you for your input I very much value any information shared within this forum what ever time warp it comes from and while it might assist me it could assist someone else who reads this thread with a vehicle from another time warp...😊

In the 1970's I had a Ford V8 that would ping and knock on Shell or Exxon fuels. BP and other cheap stuff(at the time) was OK.

Hi Bobster.

My 2009 Sigma has covered 92,000 now and regularly runs on supermarket petrol with a fill up on Shell Nitro 1 in 4 fills. I get a bit of burbling on overrun sometimes (which I enjoy). I change gear at 2,500 to 3000 revs but occasionally allow her to go to 5,500 in 3rd if a Yaris wants to show me how quick it isn't .

This doesn't help your problem I know, but I suggest it's NOT a fuel quality issue.

Cheers

OK.....sounds a bit boy racer ish but perhaps some higher rev drives would help. An "Italian tune up " style. Not exactly redlining but good use of revs. To the upper regions. It's a bit like the clearing out of diesel particulate filters after too many slow, low rev runs causing the warning light to come on and the faster extended run burns off the muck.
Just be sensible where and when you do it!

I have a Plus 4 with throttle bodies so perhaps it is a bit difficult to compare with the 1600cc engine however I would seldom use 5th at 50kph (30mph). I would doddle along in 5th at about 60kph (37mph) but it is quite happy at 70kph (43mph). I would have to check but I think that is about 2,000 RPM in 5th. If I want to accelerate for passing, or if I am playing boy racer, I change down to have the engine running at at least 3,500 RPM and up to 6,000 (rarely) before changing.


I have the opposite problem in my daily driver. It is a diesel and much slower revving than the Morgan. If I have been driving the Morgan for a while beforehand I often find myself driving the Alfa in 3rd or 4th gear instead of 5th or 6th.

I have a sigma 1600. At 30mph I would be in 3rd.
I used to have an 1800 4/4 and that used to sound as if it was pinking but in fact it was the gearbox rattling at low revs (about 1500_1800 I think). The factory told me it was within toleration limits! But it really did sound like pinking.
Nick

PS. My rattle was from new and was worse when the gearbox had warmed up. I proved it was gearbox by covering the tunnel with very thick material which did indeed quieten it down. It rattled under load mostly.
My 1600 does burble on overun sometimes but I like that....and anyway, compared to my Abarth 595 (which actually backfires on gearchange if I'm pressing it) it's fairly subtle.
Nick

I originally had a lot of pinking issues with my 1.8 and it was so annoying. It was resolved with a later map so it wasn’t the old tranny box in my case. Now I occasionally get the odd pink for a fraction of a second until the knock sensor kills it if I labour it . That’s normal I understand and perfectly liveable compared to before. Interestingly that in the winters months I have nothing at all but as soon as the warmer weather comes and the engine is up to temp I can occasionally detect it again despite the ECU reporting the same engine temp throughout the year. Something is thermally boarder line so I have an experiment to try at some point to reduce my coolant ratio from 50 to 30%. That should improve the coolant’s specific heat capacity by around 10%. Hopefully that might get a little extra heat away from the plugs and eliminate it altogether but it’s not a big priority any longer.

At least I can say that during 40.000 plus km with my 2014 4/4 I never had a pinking issue. She gets good fuel and I like to rev her but when cruising in third in the villages there is no pink even when flooring the throttle at low revs. I would follow the advice given here to let check all sensors by a professional engine specialist because what you tell sounds like she runs out of specs. I would also check if the variable cam timing works properly.