No power to coil

[Monkeyfinger]

Trying to bring her back to life after extended slumber. I have cranking but no 12v to coil. Before I start looking between ignition switch and coil are there any usual areas of weakness that I should also check? Thanks in advance

[mgcjag]

Yes...coil feed goes via ignition switch and rev counter...do you have the wireing diagram.......you could just run a temp feed from tne battery to coil if you want to start

[Monkeyfinger]

Thanks Steve.. I do have wiring diagram and temp feed is a great idea. I will drive deeper...

[mark10337]

Check the 2 white cables on the plug behind the tacho. With the ignition on, one of them should be live. When it is plugged into the tacho, both should have a voltage. The 2nd white cable feeds directly to the coil. I've known this to be a bad contact.

[Monkeyfinger]

Will do...short term
12v separate feed to coil in place. Still no start...found I had managed to transpose the suck and blow pipes on my new fuel pump ..corrected that, lots of cranking but still no start. Retired hurt to bottle of wine...must have been 2nd or 3rd glass before I remembered that I had put the spark plugs in hand tight after cleaning. Wondering if lack of compression might have an effect on starting elderly 4.2...

So tonight I will try again. I will report back

[ralphr1780]

A clear conclusion is that wine improves the memory

[PeterCrespin]

12v separate feed to coil in place.... Wondering if lack of compression might have an effect on starting elderly 4.2...So tonight I will try again. I will report back

Dear Richard

No, the plugs being finger tight would not prevent an otherwise OK engine from starting. While they are loose remove them altogether and lie them in contact with the head to check if they all spark while you crank. Don't replace them until they do.

The coil HT lead should spark when you connect/disconnect the temp direct power lead, provided the points are closed.

[Monkeyfinger]

Thanks Peter...found plugs were tight anyway, so I will follow your process. I know I am getting power to plugs as I am using sparkrite plug caps. However I will still check that the plugs themselves are sparking. Car has electronic ignition which I fitted maybe 20 years ago and was running when put to sleep some 10 years ago. I hope it still works ok. Recent reviving works involved carb removal but I certainly have fuel up as far as the float chambers...i will have to start digging deeper

[Monkeyfinger]

I must have had some form of airlock to the carbs...disconnected the feed pipe union and checked flow. All seemed fine, reconnected and managed to start her up. Had to pull choke out hard while operating starter so it looks like I need to set up the choke better. I note a good thread elsewhere on this forum.

Now I can work on the coil 12v feed...I have no ignition light so I suspect issue with feed to and from the tacho.

[mark10337]

If you have no ignition light either, it sounds like the white cable from the ignition switch isn't getting power. I've seen a setup where there are 2 white cables coming from the ignition switch. One feeds the ign and coil, the other the rest of the electrics. If you have that setup it could have come lose.

Anyway, best way is to trace back along your wiring from the coil -> tacho -> Fuse box and see where you have power and where not.

[Monkeyfinger]

Thanks Mark...its amazing how many electrical problems arise after a few years slumber! I will check the wiring as described. Think I'm going to pop the top off the dash and gain better access to the gauges as I've got some bulbs to check anyway.