5 replies to this topic

[Alex1380]

Right i think i have a weak spark. i have check and i only have 6volts across the coil. this can't be right or good, but what does it mean???? what could be the problem? would a flamethrower coil and fancy HT leads be helpful? I have a luminition obtronic kit does this make a diffrence, also the electrinic ignition comes from the Neg on the coil is that right?????? works so i don't know.

[Pavel]

Do you have ballasted ignition? That should give you either 6v or 9v depending on the system. If so, you need to have the right coil for it.

[dklawson]

Six volts can be right if your car has a ballasted ignition system.

Since you have a volt/ohm meter, mark and disconnect all the low tension wires from the distributor. Measure the resistance across the two spade lugs ( Coil (+) and Coil (-) ). If you measure something between 1 and 2 ohms, your coil is a ballast type coil and somewhere there is a ballast resistor supplying voltage to the coil. A "standard" or non-ballast coil will measure about 3 ohms.

Here's the succinct explanation of ballasted ignitions: To give the car a hotter spark while cranking the engine on the starter, a full +12 volts is supplied directly to the coil (+) terminal. This usually comes from a terminal on the starter solenoid. After you stop using the starter, the coil gets power (through a dropping or ballast resistor) from the "usual" source, the ignition switch. If you notice a pinkish wire on coil (+), this wire IS the ballast resistor. The current flowing through this ballast resistor/wire drops the operating voltage of the coil so the spark isn't "too high".

Don't be tempted to run a ballast type coil off of a full +12v. It will work, but you'll burn up your ignition points very quickly.

As for the weak spark, how do you know it's weak? If the color is orange, start with the cheap fixes. First (temporarily) disconnect/remove the condenser to see if the spark "looks" stronger (blue). If this helps, install a new condenser. Don't be tempted to run without the condenser or you'll burn your points up just like mentioned above. Also remember that you shouldn't be running resistor plugs with resistor wires as this will also give you a "weak" spark.

[TimS]

just slitly side tracked question... do you need a condenser if you have electronic ignition?

[dklawson]

Solid state ignitions don't require a condenser. The purpose of the condenser is to eat voltage spikes and quench arcs as the points open to prevent the contacts from burning. Since you don't have points, you don't need the condenser.

[Dan]

But electronic ignition modules do require to not be fed from the ballasted feed, they want the full 12v and that won't be helping.

9v ballasted coils never see 12v, that's why ballasted ignition was invented. You don't get a fatter spark at startup since the starter load reduces the battery output to around 9 volts meaning the coil is always at the right voltage as it takes it's unballasted feed when cranking and a ballasted feed the rest of the time. I suppose the 6v version might see a fat starting spark though which is probably why it was changed to 6v. I would think you'd burn the points out fairly soon though with repeated starts but then I gues that's why they came up with the wiping heel points.

Sorry, just thinking in the keyboard.

You need a seperate ignition fed and fused supply to power the ignition module ONLY, NOT THE COIL. Ideally this should be fed with white cable if you can get any (Halfords do it).