Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Intermediate rough running

And a couple more of wiring "found"





The two wires were just laying there.
I assume the plug is for the module?

And, the module is to look like this?????

That's the one by the looks of it comparing it to mine. If there is anything we can help by comparing just ask away one of us will know or have seen it before.

I guess this is the diagram you have of the ignition circuit. Not helpful but I don't see a purple anywhere in the area.

Just been out for an evening run in the car and checked the Dizzy identical and indicating similar rotation 🙏 which is always a good start

I always follow the maxim of start simple and build up the complexity, I have a 94 +8 so the same as yours.
With the low mileage when was the fuel in the tank last used and replaced with fresh?
The RPI ignition amplifiers are normally reliable, mine has 55,000 miles on it with no problems. Before you start dismantling and removing make sure there is a good clean earth with the black wire, this is a common issue and will cause intermittent issues. It is also worth checking all the connections to the coil to make sure they are clean and tight.
Next I would check all your ignition leads, I assume they are original which will make them 27 years old and could well have dried out and cracked, be good to replace them anyway if original. As suggested above starting the engine in the dark and looking for any arching is an indicator.
Look in the dizzy to see if there are any tell tale arching marks, if yes replace the arm.

Sometimes a good blast is needed to clear the cobwebs especially as it appears to have just been doing short trips (which are worse for an engine), a good 30 to 50 miles(I know you have done 30 miles on trip 2 a couple more may good) to get everything to temperature and proper running can tell a good deal.

Thanks Britmog: I have put about 500 miles on the car since I bought it. Running 93 octane gas. Have had no problems until last Saturday.
I will check all the items you suggested tomorrow and see if there's a difference.
More that happy to give anything a go to get things sorted out.

Tom

Not sure if these are going to help you any more than Rich's photos , but just in case I took these today









The ignition module is mounted on the aluminium bracket just behind the coil .

Like Rich , I can find no purple wire , mainly black and white.

I know that Bruce has a lot of experience in Morgans and he has experienced no issues with the RPi amplifier, but my experience is contrary to this . However the points he makes about chasing down the obvious possible faults first make a lot of sense.

Darn. Now I have to find an aluminum bracket. Always something!

Today: removed distributer cap/rotor. Looked just fine save for slight erosion if the inside terminals. Oxidation came right off. Nothing odd about the cap or rotor.

Checked and cleaned and waterproffed the col terminals. Checked the black ground wire with a true RMS voltmeter and found virtually no resistance to ground.

Did find the vacuum hose to the vacuum advance was off. Fixed that.

Next try after the weather cooperates.

Thanks for all your help.

Tom

OK I think I have it narrowed to fuel delivery.
Coming home today (6 miles) I could only drive if I barely pressed on the accelerator pedal. If I pressed too fa the engine would just start to die out. Let the accelerator up and it smoothed out. I could accelerate, but VERY slowly.
When I got home and inside the garage I pressed the accelerator down (in neutral). The engine just died. Tried an immediate restart and best I could get was Idle. About an hour later I tried again. I got the normal whirring for a few seconds and stopped. Started normally and ran great.
When you initially turn the key on you hear a "whirring" of the fuel pump for a number of seconds. That's when it's pressurizing the system. Mine will do that, but if it lays idle for some time there's another noise following the whirring. It lasts for a couple of seconds also.

How difficult is it to get to the fuel pump?

Is the second noise coming from the pump in the rear or from the front? The fuel pump is external on the shelf behind the drivers seat on the opposite side to the battery, it is a little awkward to get too but not too difficult. You might have some crud in the fuel system and it could be worth adding some fuel injector cleaner and running the engine to flush through the system. Over here I add Marvel Mystery Oil about every other tank fill which helps keep the fuel system clean especially if the car has not been fully used for a while. I would also check that the vacuum hose to the pressure regulator is attached and not damaged. At some point going forward you might want to consider replacing the fuel pressure regulator with an adjustable fuel pressure regulator with built in pressure gauge, not a difficult job. The advantage of this you can see and set the correct pressure values for the system pressurizing and running. As you said the engine ran normally after waiting an hour would suggest the pump is working as it should and the issue is at the front end.

I also note you said the vacuum hose to vacuum advance was off and you refit it, did you check to make sure the hose was sound and the dizzy was advancing? Take the dizzy cap off remove the vacuum hose from the plenum and suck on the hose whilst observing the mechanism in the dizzy, it should move a few degrees, if not you have a leak and will need to replace the hose.

I think on your dizzy the original ignition amplifier will attach by two screws to an integral bracket that is on the side of the dizzy, it does on mine although mine is a 35DLM8. I will go with MOG 615s experience and if you have the original amplifier then it is an easy fix to put it back on and try it.

As you live in Illinois do you know Keith at Northshore Sportscars, if you don't you should, Keith is extremely helpful and the best Morgan Mechanic this side of the pond.