Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) 2016 Roadster multiple erros on ECU

But can a sensor fail to short ? I was thinking about have a good look at the fuse box first (I have seen that problem before), then failing that disconnect all the sensors and then see if there is a short. hopefully there wont be and then ill connect each one in turn - What do you think of that approach?

Chaps, does any body know a part number for the upstream / downstream sensors - from the factory they are charging over £200 per sensor . But I think Bosch make them . They seems to be 5 wire , but they have about 2 feet of cable on them ! Answers on a postcard please!

Only as an idea I looked at Mustang 3.7 V6. It is a US site, but even with shipping the price would be good in comparison. I don't think that Morgan uses any other sensors than Ford does?
Even in UK Ford Mustang sensors should be cheaper than "Morgan" sensors.
BTW I have always had good experience with NTK.

https://www.rockauto.com/en/catalog/ford,2015,mustang,3.7l+v6,3307632,exhaust+&+emission,oxygen+(o2)+sensor,5132

If you get up close with your mobile & good lighting you may be able to get a shot of the part nr on the barrel of the sensor & as Heinz suggests NGK used to have a cross ref look-up in line

Mad !!! Its a wiered one . I can find the part with the same reference and the right connector, NTK but the cable length is about 12 cm and the one off the Mog is about 60cm. I cannot find the exact one anywhere . I will keep digging . I have a feeling it may not be standard hence why Mog charge £285 per sensor. Strange!!!

What's the price difference ?
Are you confident soldering wires ?

IIRC mine has a lot of spare cable looped & cable tied along the wing stay

I warn against soldering O2 sensor cables. I did it once because I did not have a new plug (I can really solder). It did not work, the values were wrong. During soldering there is often a too high contact impedance. Since then I only use mechanically pressed cold joints for such sensitive wires.

But where I say this, I would buy the 4 O2 sensors, 2 each for up and down stream of the Ford Mustang. If the connectors are different, you can take the old ones and connect them cold pressed.
If even the instruments and the unchanged ECU are taken over from the Mustang into the Morgan, one can do nothing wrong in this way, because nobody could or wanted to change or even reprogram anything at the Mustang. I would blindly trust to just buy the Mustang parts.

Apologies for late reply, just noticed your post above. As you say a good clue allowing the search for cause to be narrowed. Looking downstream from engine fuse 13 we have all four oxygen sensor heaters (sensors themselves within connect direct to PCM as with cam sensors), evap cannister purge valve and all four cam solenoids. Once the fuse blows all these feeds would be lost explaining the fault codes you originally mentioned. Although any one or its wiring could be at fault, it does look like the oxy sensor heaters would be first place to look if only because they are under greatest thermal stress.

Note my wiring diagram shows both upstream and downstream oxy heaters fed from same fuse. Cannot find what engine fuse 14 you mention feeds other than its labeling as VPR3 to PCM, so unless you know otherwise that may be a red herring.

Good luck with search!

ETA: it may be possible to narrow search down on the oxy sensors, assuming one is faulty and that fuse 13 blows before engine started. The downstream pair are fed directly from this fuse with yellow/white cable that splits to feed sensor heaters each side. The upstream pair are also fed by another yellow/white cable from fuse 13, but in this case via pin 16 on engine loom connector C58 (which also feeds cam solenoids). It's possible if you broke this connector then tried replacing the 15 amp fuse to check whether it still blows, it would allow further narrowing down of root cause. Unsure if you need engine running to prove and if it would start at all with connector broken though, hence comment at start of paragraph.

If it's possible to do yes. Given its engine fuse 13 blowing its likely an O2 sensor heater that's failed possibly as you suggest to a short within, although wiring to same is a possibility.


Can confirm the upstream O2 sensors are six wire and downstream four wire, with two of those for the heater in each case. The voltages measured by the sensor's drop to fractions of a volt with a warm engine so would advise against extending cables to suit installation due to any inadvertant resistance creeping in to the sensor circuit, in turn affecting fuel mixture when system goes into closed loop.

Not convinced the items are standard 3.7 Mustang either given the custom Morgan tubular manifold's and exhaust system. Add to this there were changes to Mustang engine spec after 2013, which I believe involved a change of O2 sensors. FWIW the Roadster seems to adopt the earlier spec. and this is certainly true for the air filter element.

This is interesting and important information, Richard. I'm sorry, I didn't mean to cause any confusion, I just wanted to help with the idea of how to get the O2 sensors cheaper than buying them from Morgan. At least it would be worth searching the internet and comparing prices of the right parts, whichever the right ones are, and if they are the culprits at all.