Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Severe misfiring on 3.7 V6 Roadster

Thanks Jon. Will have a look again but MAF sensor spotless when last checked as I mentioned to Heinz.

Agreed, I know your maintenance is spot on, but it's one reason I don't use K&N style filters any more and that 3.7 gobbles a LOT of airflow

My own view having sold very many for motorbikes is that K & N filters work fine as long as not over oiled. They wouldn't be such a popular option otherwise. They colour the oil red which allows you to put just enough on such that once soaked in to cleaned material a uniform red tint is acheived. Clearly it's possible for over enthusiasm here though.

When last checked after maybe 15,000 miles with K & N slab filter I rinsed sensor with aerosol cleaner catching residue on clean paper towel which remained completely clean. I will check MAF sensor again though since maybe 10,000 further miles and K & N was cleaned not so long ago.

ETA: just checked and sensor clinically clean as before.



Apparently should be checked and cleaned every 10,000 miles so it did need doing.

For fun some time ago I did the maths on that point and it showed that at full chat it would evacuate the air in my double garage with tall pitched roof in around 5 minutes!

Richard talking to Alan Braithwaite last night he has had issues with the fly by wire sticking.

Bit strange, as there is no physical link, so nowt can actually 'stick'

No physical link but I guess the actuators could stick ????

In theory you could get a sticky potentiometer at the pedal end or glitchy stepper motor at the throttle body butterfly

Discussing this point tonight with another TM member, we concluded that if the FBW link between throttle pedal had any lag it would simply slow the revs rising but not cause a misfire. In my case all came good with some boot and load on the engine, and issue was only on very light throttle low speed conditions. Worth following up though if issue happens again.

As mentioned earlier it was interesting to see the throttle range dial I'd configured on my OBD Torque app when connected to car via bluetooth link to OBD2 dongle. With just ignition on the dial, starting at 17%, followed pedal movement. As engine not running the stepper motor driving throttle butterfly could be heard following suit.

Had an issue many years ago with Val's Shogun Pinin which also had FBW throttle. Car went into limp mode with MIL light on, and barely allowed us to get home, although don't recall any misfiring. Fault found to be sticky throttle spindle such that stepper motor couldn't react and cured by exchange throttle assembly.

According to Roadster engine schematic there is a stepper motor actuating butterfly to open or close throttle and controlled by position sensors which also control the ECU power demand loop. I would imagine if stepper motor fell out of kilter with position sensor this would throw a MIL warning and probably trigger a limp mode as above.