mk1-forum.net

Anybody who can tell how you test:
Condensor
Ign. coil

Tank you

Tommy

To test a condenser properly you need an LCR meter. Some multimeters include a capacitor check that will tell you if the unit is good. A rough screening test is to use a regular multimeter set to measure resistance. Put one lead on the foot of the condenser and while watching the display hold the meter to the terminal on the condenser lead. Try not to touch both probe/terminals with your skin as you will affect the readings. (Touching one terminal is OK). What should happen is the meter will show some resistance value and this value should steadily and slowly increase until the meter approaches nearly infinite resistance. This behavior is your meter charging up the condenser. If this charging does not happen, the capacitor has internal leakage or is shorted.

You can make resistance measurements on a coil but performance testing is the only real way I know to determine if they are OK. With a multimeter set to measure resistance, mark and disconnect the low tension wires from the coil. Use the meter to measure across the terminals. A "standard" coil will have resistance from about 2.5 Ohms to as much as 4 Ohms. Nominally... they are 3 Ohms. A ballast ignition coil will measure somewhere between 1 Ohm to 2 Ohms. A second test you can perform is on the high tension circuit. With ALL the wires removed from the coil measure the resistance between the King (center high tension) terminal and either low tension terminal. You should measure several thousand Ohms. This value can range quite a lot because no two coils will measure the same and different brands will be different as well. A coil's resistance may measure fine and still cause problems. The coil may not show any problems until it is hot or until the engine is trying to run at high speed. If you have a tachometer it can shed some light on running problems.

Sudden jerky motions of the tach indicate problems with the low tension circuit. Always rule out the cheap things first like replacing condensers and points. If you have ruled out the points and condenser and the tach continues to bounce and jerk, consider replacing the coil.

Probably not really the type of answer you maybe looking for and not necessarily from 'Genuine Knowledge' but rather experience;- it is cheaper and quicker if you suspect one of these components to substitute them with replacements (especially in the case of the capacitor), perhaps one at a time. And yes, I have a test bench.

Testing on the Test Bench can lead you quite astray as not many test benches also simulate vibration (as dkl has mentioned) or temperature. I've had plenty of coils that appear and 'test' fine but when they are warmed up in the engine bay, miss-fire.

Careful examination of the points will show not only if the Capacitor is faulty, but an incorrect value for you coil as one side will erode quicker than the other for the wrong value and just simply burn & generally miss-fire if faulty.