Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 3.9 +8 starting problems

Ivo that is a new piece of information that might give us a useful clue.

The immobiliser in the system can malfunction, so in order to check this remove the fuse to this item and try again. You can run without this fuse with no worries, but of course it means the car is not protected as securely from attempted theft. I would also replace the battery in the key fob, that will also help turn the immobiliser off more "positively"

Secondly the 14CUX "Hotwire" system ecu is only controlling the fuelling of the engine. The ignition is handled by the distributor. It was not until the introduction of the Lucas SAGEM ("GEMS") system (about 2002/3 on the +8) that both systems were controlled by the ecu

Check the connection between the ignition harness and the engine harness,a white two pin connector
Directly under steering wheel and on rear face of bulkhead (engine harness goes through bulkhead).
I had very similar problems on one of my +8 s (2000 4.6)
I had to cut this connector out of my car and replace with better (non time expired) connectors....

Thank you for this information, Andy
The immobiliser has already been deactivated by the previous owner. But I will check, if there is still a fuse.



Thank you, Chris
Is you car a left, or right hand drive?

All the indicators you have mentioned lead to a faulty ignition diagnosis. I would first test the voltage to the coil during starting using a voltmeter ensuring a constant reading. I would think this would be correct then I would look at the coil change it for a new one then try.

If you want to test the coil you could try this method:

https://www.bing.com/videos/search?...2E70F6D732&view=detail&FORM=VIRE

If the coil appears to be OK then I would check the High Tension cable from the coil for any breaks or weakness this could be causing an intermittent spark.

Thank you, Bruce

Tomorrow, I will test the constant voltage on the coil.

Not having a spark tester, I did not test the coil as showed in the video. But I measured the coil resistance, following the GoMog procedure (page 6) and it looks good. (I think)
All high voltage leads have been replaced two month ago.

I think, the problem lies within the distributor.

I had to do it today…

While starting, the voltage drops to around 10V on the plus pole oft the ignition coil, which looks reasonable to me.

The resistance readings of the coil are 1.1 Ohms on the primary side and 4660 Ohms on the secondary (high voltage). What do you think?

I have read the thread with great interest. My amateurish notes. Ivo, you say that in some attempts to smell unburned petrol. That means that petrol is being pumped. Still, my question, does the Morgan have some sort of gasoline pressurizer? That's why my 911 didn't start. Especially when it was warm. And that's how the problem started for you.

Here's another idea, I had a porsche 928 that wouldn't start because "temperature sensor 2" was broken. It thought the engine was warm when it was cold. Does the Plus 8 have a similar kind of sensor?
What I basically mean is if the ignition coil and all cables and plugs are ok, can it be a sensor problem?

I'm still rather favouring the ignition amplifier, they breakdown and die and that is the symptoms you have described Ivo, we have established clearly with your checks that she is fuelling and the coil ist in ordnung and all the leads have been renewed/checked.

Another check I would carry out to eliminate this or prove it is to remove the distributor cap completely and check very carefully in good light conditions to check for any signs of carbon tracking interior and exterior. I once had this on my Scimitar (V6) and it started off with the odd misfire and finally manifested itself in a non start after a very fast hot run on the Autobahn in Germany.
It just shorted out the coil input to the distributor straight to ground/earth.

Good luck.

There is an electric fuel pump, that runs for a couple seconds and builds up pressure before starting, if that is what you mean. Don‘t know about a temperature sensor.



Thanks again, Richard,

I will certainly keep the ignition amplifier in mind. The car is scheduled for the shop for next Friday, but I could ask them, if I could borrow one, if they have one in stock.

The distributor cap is brand new, with about 500km driven, so carbon deposit shouldn‘t be a problem and the engine turned smoothly until the last moment. To be honest, I hesitate a bit to remove all the cables, in order to remove the cap. There is so little space, for adequately marking their positions. I still might do it, though…