Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2018 Plus4 GDI Wiring diagram

Just back from Britain my lovely „Plywoodracer“ has some worries. Have a look here: https://www.talkmorgan.com/ubbthreads.php/topics/824638/1

Now I look hopeful forward to hunt and eliminate the electric bug or LUCAS the god of electric darkness…

For this next step I need a wiring diagram for the 2018 Plus4 GDI.

So for the diagram or an idea where it is, I would be happy.

I‘m shure it‘s a very bad english… but I think you enjoy it and have the idea.

Greets René

Hi René, you can download the parts book with wiring diagrams here. The wiring diagram for the full Plus 4 chassis harness is on page 218.

Thank you Richard,

after enjoy some time to read the wirediagramms I realize how they work. More or less. After some expirience ich some classic „LUCAS“-diagramms from old MINIs and Harleys the MORGAN diagramms are a little bit different.

In the moment I‘m realized the first step: I need Page 213 for the wires and page 218 about the parts/connectors. And than puzzle back for to look what I must check…

But not shure about page 218 part C93 and C94? I think that’s the ignition lock?

Greets René

Be careful René, page 213 refers to wiring on +4 models up to but not beyond 2014. The correct schematic for your car is the one for GDI models from 2014 onwards on page 218. All the information you need for the chassis loom is shown there (even lengths of each leg) but given the increased complexity its just not practical to display this in the earlier format showing individual wires. Instead each end of a cable within the loom has a unique numerical identifier pre-fixed with it's colour(s) shown in coded format. I find this a far easier and more accurate method of tracing wires, although it can be frustrating occasionally to find the matching opposite end. Some knowledge of the wires purpose helps here. Equally frustrating is the ommision of dash wiring on these later models.

Note C93 is one of two connectors to the wiper stalk switch (wiper delay) and C94 one of two connectors to the light stalk switch (indicators and headlamp dip). Do you have a problem with either of these?

Thank you Richard for this information!

Now I see, -2014 and the difference 2014-.

The next step is undo the cowl and have a look at connectors and the colour of the wires. In the diagramm I miss the sensorring at the ignitionlock and the immobilizer warning light. But I‘m shure I‘ll find them.

In the moment when I understand it right, there are two Electric System working together to fire up the MOG.
One usual system to turn the engine and a second system switched by the immobilizer for the spark and fuel?

Greets René

I can only add that the "key present" sensing is not used on the Rover 820 series ignition switch used. As used therefore its a very simple device in itself and unlikely to be a cause of your "no spark" issue.

The ignition relay (middle one of the three) should energise with ignition on. Maybe with a helper you can feel/hear it click when ignition is first turned on, noting that adjacent fuel pump relay will also click on. It's coil is fed from same ignition switched +12v supply as fuel pump relay (white/green wires) supplied by engine fuse 11 (5 amp - relay drives). Unlike the fuel pump relay the ignition one is triggered by a ground from the ECU pin 106, on yellow/blue wire to relay coil. Note this connection routes through chassis to engine loom connectors (C48/C111). Obviously if conditions such as immobiliser disabled are not met then ECU will not provide this trigger.

Hope this info helps in tracing issue.

I’m sure I’m repeating this. But have you checked the “crash cut out” ? If. Your car has one. My 2011 4/4 has one on the fire wall in the engine bay near the wiper motor.
After I put mine into a crash barrier the engine would crank but not start. Pressing the reset allowed the car to start.

Good point Bob excepting the cutout only interrupts power to fuel pump and René has no spark.

So in summary, when I understand right (schoolenglish), the main area for looking for missing Volts is the fusebox?

Greets René

From the information you have given so far I've no reason to suspect you have low volts. Measuring at sensors is meaningless since some work with a reference voltage in the 3 - 5 volt range. You could check with a multimeter the voltage out from the two relays you have changed though - ignition and fuel pump with ignition switch on of course.