Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Current MMC Stage 1 offering

In a similar situation, when you purchase a new Harley and go stage 1, which is a free flow AC and exhaust, a re-map is usually performed. But because of the popularity of the Harley, just about any dealership or indy can dyno and tune for the new parts.

Granted LOTS of people just purchase the new exhaust and AC and run as is and are probably not going to do any damage.

But for the best performance, it's best to re-map the ECM. Without it you may get a bit of decel popping in the exhaust.

Even a stock Harley can benefit from a dyno tune to get out of the extreme lean running to meet the EPA standards here in the US.

Dan - it of course makes sense to me. The ambiguity doesn't. Personally, I'll reflash because I want no headaches and the best performance possible. Let them put their best foot forward.

I wouldn't be surprised if this also has something to do with the geographic availability of 93-octane in the US. CT has it. But why quibble.

"...it may develop fault codes of bad sites left and bad sites right."

Well, this is certainly clear (not). What the heck is a bad site? Sounds like something you shouldn't point your browser to :-)

I have a 2017 ordered with Stage 1 kit factory installed. If there is a way to examine or dump my ECU to see what mapping or version is installed in it, I'm happy to do it. At the time I ordered it, I never heard that there was any change in the ECU mapping with the Stage 1 kit, but who knows.

The ECU setups in our cars are predominently Closed Loop, which means the ECU sniffs the exhaust content via the Lambda (O2) Sensors and adjusts the fueling accordingly. This is called Fuel Trim and these trims are stored in various data Sites in the ECU's 3D map. All sites have a range of permitted values and if these are exceeded, then the Engine Light can be fired. There are plenty of OBD2 Error Codes out there that include the words "implausible value" or "out of range" and these show values measured that are out of range.

EU3 cars were actually setup fairly rich as far as I am aware, which meant that the fitting of a free flowing Stage-1 setup (from any source in truth) would normally have the required level of fueling available already, but if the Lambda's decided that they needed more (or less) fuel at any particular point, the ECU would 'trim' at that site. Too much trimming and a Check Engine light would fire.

So in my view an EU3 car should be fine without a re-flash of the ECU and even if it did fire a CEL, then a simple reset with ProTune would have you on your way again. A CEL caused by out-of-range fuel trims is unlikely to have any noticeable effect on how the car drives though.

The subtlety may be in it being a 2017 US spec M3W and it could well have different mapping to the Euro3 M3Ws

In particular if it is setup to run on 93 octane that might reduce the tolerance in the closed loop trimming.

Unfortunately the locked ECU limits what you can read with ProTune but you can see the software version and any fault codes.

I would be tempted to fit the Stage 1 and see if the engine light comes on. If not you're good to go and if it does then the ECU can be removed quite ealsiy and sent back to MMC.