Starting problem

[RollyTG]

My 3.8S is driving me insane. It has been laid up for quite a while as I was repairing my broken transmission mount and a few other things as well. Have started it and run it during that time. Two weeks ago I got it fired up and drove around a little - oh,joy oh joy. But then it had a serious meltdown and would not go. The problem was a broken rotor cap. replaced that and then she started just fine - but here is the problem. Every day this week it has started easily, runs nicely for a minute or three, then just dies. Subsequently it cranks but will not start, just fires randomly and intermittently. Spark indicated by in-line test light is pretty poor at that point. It sounds like it wants to start but it appears that the spark is for some reason no longer strong enough. Leave it for a few hours and come back - starts just fine but then dies again. Any suggestions as to what might be going on? I desperately want to get it running enough to transfer it from it's current home in a friend's workshop to my recently completed new garage at home so I can get to work on more serious refurbishment.

[Treetrimmer]

Hi there,

I'm not claiming to be an expert, but I would be looking to replace the ignition coil. They are relatively inexpensive, so would be a good starting point (not meant to be a pun!) for eliminating items.

Good luck, Richard

[cass3958]

Funnily enough I am going through this exact problem myself at the moment. Started and runs for a couple of mins then stops and will not restart.
I have changed the coil, plugs, check HT leads, new fuel filter, checked fuel pumps, carbs were rebuilt only last year. I have had the distributor out and checked the module on the electronics was working. Checked the timing and reset the carb settings.
Gave up for the night and put the battery on charge over night.
Next morning for some reason it started and runs again perfectly.

I had taken out the fuel pumps and cleaned all the points. Not that they were not working but I felt that this problem was only happening on the left fuel tank and the fuel pump on this side had been converted to an electronic SU ie no points. So on the right tank the car runs fine but on the left there might be a problem with fuel pressure with that pump. I am looking to change it out but in the meantime I am just running on one tank.

The other thing it might have been was enough power in the battery to turn the engine over but not enough to turn it over and throw a spark at the engine. This would not account for the running and then stopping side of my problem though.

[RollyTG]

Thanks Rob and Richard. I am getting a bit sick of buying coils at 35 bucks a pop. Today I will start it up, let it run until it stops, then immediately swap out the coil with the spare from my MG and see if that fixes it. If it doesn’t then I will replace the distributor cap with the one I took out a while ago.
If all that fails then I will have to look at fuel as the problem. Another related thing maybe - the fuse for the oil, temp, fuel and ammeter has blown out twice. Could that be a sign of something like the generator/regulator making too much voltage? Today’s the day I hope. Good luck Rob.

[John Quilter]

To rule out your last concern, get it started and while running put a voltmeter across the battery terminals and see what you have. IIRC it should be 13-14.5 volts, perhaps depending on engine speed.

[BOB67S]

If you've not converted to electronic ignition , for the cost involved I'd change the points and the condenser. When was the last time the distributor had
a small drop of lubrication on the shaft ? A couple of drops of oil should do it , wipe off any excess.Advance weights might be sticking a little. With the fuse blowing did you clean up the metal where the fuse sits ? Nothing distorted / looking out of shape and therefore not gripping correctly ?
Ignore if not applicable. Bob