Ignition woes...

[interloper]

I've been having fun and games trying to get my old Scimitar to start, I thought this would be relatively simple....

So far I have good electrical power, power to the coil and from the coil to the low tension side of the dizzy. The starter motor turns just fine, the points open and close on the distributor as they should and the the fuel is pumping but it wont start.

I have pulled the lead from the dizzy to the coil and fitted a spark plug directly.... No spark, when turned over? I then pinched a known good coil off another car, tried again. same issue. So what am I missing? Is there a relay (as one diagram suggests) between the ignition and the coil, or is that for automatics? I really cant understand why I'm not getting a spark at all?

Any suggestions appreciated!

[DocArbathnot]

Condensor?

[interloper]

The condenser in the distributor? Do you know what readings I should get on the multimeter for it, should it have 12 ish volts at either end in normal running?

[DocArbathnot]

I don't know, I've gone electronic. I do know a lot of st condensors rotor arms and the like out there. Might be worth getting a new rotor arm and condensor from the distributor doctor.

[jimbob82]

interloper said:

I have pulled the lead from the dizzy to the coil and fitted a spark plug directly...

is this a typo? do you mean from the dizzy to a plug?

[interloper]

jimbob82 said:

interloper said:

I have pulled the lead from the dizzy to the coil and fitted a spark plug directly...

is this a typo? do you mean from the dizzy to a plug?

Surprisingly no! The obvious test is pulling a lead from the dizzy to a plug, fitting another plug and resting it some were earthed (then check for a spark). To test that the coil is kicking out the big volts you can disconnect the king lead from the cap and (depending on the shape of the connection) slot a spark plug in and repeat the HT lead test, because of the coils connection to the distributor via the low tension side it will create a sequence of sparks, when you turn the engine over.

[andyiley]

DocArbathnot said:

Condensor?

^^^^ What he said.

To answer your question after this post. A condensor is basically a capacitor. So if you get a resistance reading, it is definately dead. If you don't, it could still be dead.

They generally cost peanuts. That would be my first choice.

[Locknut]

I'm not familiar with this car. Is it the old type Lucas dizzy in which the points have a long, curved spring? It's very easy to connect the LT wire from the coil wrongly so there is a direct short.

Check out the condenser first and come back if that does not work. I will have to rack my brains to describe the correct sequence of spring, insulator, nut and connecting wire.

[Jimmyarm]

To check if its the rotor arm/cap, pop the top off the dizzy and get an assistant to turn it over. You should see the spark jumping the points. If it is, then its a problem with the rotor arm/cap or leads. If it doesn't then the issue is probably the wiring (lack of/bad earth) in the distributor itself if you have power at the coil.

If you google the type of distributor you can probably find a pic of what the internals should be wired up like