Talk Morgan Forums Thread Like Summary - Dave W, How could you?

Dave W,
How could you sign off your page in Miscellany Just when we were about to find out how your new cat works and all the details?

My 4/4 Sport with the Sigma engine and Librands 4 branch exhaust headers with 200 cell Cat fails the MOT every year!
I'm waiting on your news before changing mine to a 300 cell Cat and finding out how you went about it?
The Librands header ends with a triple bolt flange which the Librands Triple flanged Cat bolts onto, ( that's a bit of a tongue twister), The only Cats I can find seem to have only 2 bolt flanges?

Come on Dave, get back and "finish what you started" That's a song isn't it lol

Admittedly an AI overview but it makes sense.

Yes, a new catalytic converter needs a proper break-in, often involving a specific driving cycle or heat-up/cool-down period, to seat the internal matting correctly and allow the car's OBD-II monitors to reset, which is crucial for passing emissions tests and ensuring it functions optimally to meet regulations. Failing to do the break-in can lead to reduced flow, premature failure, or issues setting the readiness monitors needed for inspection.

I think the end chapter will appear this month. Although the new cat was fine on Lambda, the mixture was way off. From memory now, the CO limit at fast revs over 2500rpm is 0.20. I got 0.5+. Way over, even after multiple tries. The only thing I had left was to reinstate the standard ECU parameters, so losing the AR upgrade.
The dealer did the deed. The CO dropped to 0.015 (would need to check, but way below).

The AR exhaust system brings a big improvement without the AR chip, so it's staying that way. Of course, the sooty tailpipe which I had from new is back. But it runs and revs fine.

None of this has made any sense Doug. The sooty black tailpipe was from new. The AR flash cleaned it up. But the MoT has always been really marginal.

The bad running a year last October lasted for about 30 minutes in a trip which lasted 1hr 30. It suggested bad fuel, or electrical, but cleared completely after getting home, apart from the return of the sooty black tailpipe.

Going to the MoT, which is 55 miles gave a clean tailpipe, but the emissions were off the scale.Remember also that when I first added the AR exhaust, I was surprised that the sensor ahead of the cat was clean, but after the cat was black soot. That was similar when I changed the cat and the sensors this time. Getting back from the MoT, another 55 miles I have the sooty black tailpipe.

The upgraded standard ECU flash, which dealers hold, was to address the sharp throttle response. Now it's not quite as relaxed as it was but nowhere near the almost undrivable state it was in from new.

It makes no sense that the AR flash was a huge MoT fail. In theory the settings can't change and yet it was hopeless, and left me with the only option, to got back to the original settings. I knew that the exhaust alone gives a much crisper response, and that the flash really only adds cleaner revving at the top end. Coming home on real roads, there was no real difference.

I can only conclude that the standard flash provides good emissions up to the 2,500/3,000rpm MOT limit, and maybe after that goes rich. For me it's not worth the bother of paying again to have the AR flash, when the likelyhood is that it will not pass the next MoT. It's classic Morgan. The same models perform differently. We've seen that on models which suffer from throttle hang.

Get the injector spray pattern and volume checked Dave!!!

After I lost the former Steve Morris Plus 4 Works Edition at the Silverstone auction, my plan was to get a Plus 4 and get the chip re-mapped and upgrade the exhaust system.

I'm now starting to feel quite lucky that I found the Roadster 110 Anniversary Edition by chance for my power upgrade!

I've probably ended up spending no more than I would have tinkering with a Plus 4, but without the emissions heartache?