Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2018 Plus4 GDI won‘t start

My girls want a few days out, so no work at the „Plywoodracer“.

As Richard says, there is a second post about the wiring. I thought it would be helpful in cause that are two different points.
The real world and the idea why?

But now, it‘s less than 35Celsius… and a new look at the car.

At first I change the most of the fuses in block B to some fuses I can test from the top! When I change them I check them. All fuses would be right. The new fuses had an open point on both sides at the top. So I can test in and out! So far the good point. The Next good point: all fuses are 12,6V (the battery is a little low in the past days).

Than I found some wires named „YU“.

At first I realized how to test PIN 106 at the ECU. Clear: the connector! With a small wire I was able to test PIN 106 in the connector. YU85 has 12.6V. But there was also YU92 at PIN113. Dead, 0,0V. So far the „small connector“. At the „big connector“ there is PIN12, also „dead“, 0,0V.

But there are some other YU connections. Must I have a look at them at first? Or are there other good points?

And I realized something about the wiring. There are some connections/ pins/ wires with the same numbers? There are two YU20, but only one YU122? And I‘m not shure about the wirerouting. Is YU20 at the feed and the end? Or are there different numbers?

Step by step forward. Looking forward to see a light. Or more volts.

Greets René

René, wires colour coded YU = yellow/blue do not all have the same purpose. The colour codes and numbers should all have matching codes at the other end of loom cable.

YU20 in engine loom is one side of trigger to injector cylinder 1 so likely not relevant.
YU85 in engine loom becomes YU122 in chassis loom and is ground trigger from ECU pin 106 for the ignition relay (the middle one). You measured battery volts on this ECU pin but I suspect this was on matching ECU plug pin whilst disconnected, so your high impedance meter was measuring permanently live feed back from other leg of relay coil. The important thing is that the ECU should ground this line when ignition switch is turned on hence triggering relay.

Apologies if I've missed it but you still haven't told us if this important relay is turning on with ignition, although I know you have replaced it. Can you check with a multimeter engine fuses 12 - 16. All five should read battery volts when ignition is turned on as previously suggested.

Hello Richard,

at first and all times, thank you VERY MUCH for your help!

As I realized that the most fuses in fuseblock B are relevant for the engine I changed them all and measured them all. And both sides. No missing Volts.

Now, when I understand right, (and you‘re right) I hat a look at PIN 106 and 113 at the connector. But I must also have a look at the matching pin in the ECU? For do it in the right way… I had connect the big connector and pulled the small one of ECU for to measure the pin?

So a look at PIN106 at the ECU and undo the sparewheel for a look at the fuel relais would be next.

About the digit/numbercode of the wires. That‘s what I was affraid about. It‘s not easy A1 at the start and A1 at the end… it changes in a mystery way.

Greets and regards René

The wiring schematics for the most part are correct, particularly 2014 on, so there will always be matching codes for each end of a cable within a particular loom. This may be at a bombtail though. When one loom connects to another the individual wire colour code (usually) remains the same but obviously it's a new wire in the other loom connector so has a different identifier.

If the volts are there at the fuses I mentioned then we can assume the ignition relay is working correctly so no need to check further in that area.

Can I suggest leaving the ECU connected and checking at the important end. In the case of fuel pump it's as close as possible to it. Can you hear it running though on first switch on?

Yes, there is a sound from the back of the car that sounds to me like the pump.

But for to be shure I‘ll undo the toolbox and also the sparewheel carrierer for to measure it. Don‘t trust a fools ear… ;-)
If it isn‘t too hot I‘ll do it this afternoon.

And: can I disconnect the fuelline somewhere for a test that the pump is working?

Greets René

Now (no worries about the heat outside 30C+) I had a look again at the plywoodracer.

„Rebuild“ the fusebox and now to the back.

Measure the fuelrelais.
WP31 12.6V, W38 2.6V and W38 0.06V and black: clear, 0V

also a look at the fuelpump.
Measure W38 to W38 for „Ohm“… a „beep“= no problems.
W38 0.0V, GB29 0.3V, SG30 5.0V, black: clear, 0V

Than a look at the engine for the highpresure pump.
GW (green/prurple?) 2.6V, NY52 (yellow/?) 12.6V

So, is there a problem about the relais (40,-EURs) or is there another problem?

How can I disconnect a fuelline for a test?

The next week turns a little hot. Up to 40C…

Greets René

René, if you have doubts about the fuel pump control module you can bypass it as below - module connector pin1 to pin 5 and pin 4 to pin 8. (Note wiring colour codes change between module and pump, black becomes positive and white return). It may throw a fault code but engine should run.



I understand they are normally reliable but bought one as a spare here recently.

I cannot comment on measurable voltages but imagine a PCM output from module is controlled via an FPC signal (white wire) from ECU pin 81.

Oh Richard, I‘m VERY happy with your help!!!

I‘ll make a bridge like you show in the picture and look (and hope hear) what happens.

On the fuelrelais there is a number, I ask Mr. Google, usual Ford Focus fuelrelais. In Mainz there are some helpful and friendly guys (and massive petrolheads) at „Autoteile Henrich“, there I buy my parts for very good prices.

Regards René

Directly after breakfast I hurry up to the garage. Than with a look in my „electric tool box“ I found a piece of green wire (very funny) and some matching pins. So I made a pair of wires for the test.And plug them in.

With the ignition on the fuelpump is working. But the Plywoodracer doesn’t fire up.

No own idea about the next step, would it be an demaged immobilizer? Or first some looks in the area of the ignitionlock? Or more behind the dash?

Regards René

Too hot to be outside. So I use the time in for to study the wiring diagram and how the fuel-relais must work.

When I understand right:

At first, the fuel relais is a „switch on relais“ („Arbeitsrelais“). So all pins must show the 12.+V

So at the relais the low voltage at YU122 is the problem. YU122 turns to YU85 in the chassis/engine connector and than to PIN106 at the ECU. So far, so good. But than I struggle.

The connector pin 106 to the ECU shows 12.6V. With an open connection to the ECU, so why there are only 0.15V at YU122 at the relais? Is this the main point/ problem?

Tomorrow I can collect my new cam-sensor and a new ignition coil, but in cause of a „familiy thing“ I can have the next look at the MOG on friday. After I fitted the new parts I‘ll try to flood the cylinders. For my thinking fuel must run, but no spark?

Also I had a look at the immobilizer wiring, there is SR292 running to the fuel-relais, but not shure how it‘s named at the relais, but all wires without YU122 are right, so no problem with the immobilizer?

With big clouds from heat and thinking over his head

Greets and Regards René