QuestionQUESTION: I am trying to get my 80 MG running after letting it sit for a couple of years. I've done all the maintenenace things but I get no spark to the plugs. The car has the electronic distributor and a coil amplifer. Is there a way to test if the coil is getting current from the battery?
ANSWER: Hi Richard,
It depends on what type of ignition system you have as to how to test the igniter, but it is easy to test the coil for power and if the coil is ok. Just turn the key on and check both sides of the coil with a test light. The plain white wire should have power on it when the key is on. Then put the test light on the other post and spin the engine over and you should see the test light pulse. If it does pulse, remove the coil wire from the distributor cap and hold it close to any engine metal and have someone spin the engine and you should see it spark with a thick blue spark. If it does you have a cap or rotor problem. If you don't get a spark or it is a thin yellow or orange spark you need to check the air gap in the dist. and check the ohms across the coil (wires disconnected) about 1.4 ohms on a coil used with a external resister and 2 to 3 ohms on a non resistor coil.
The tests of the igniter itself would depend on what brand was on the car.
Howard
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QUESTION: Howard, As I understand the first test, turn the key on and put the test light to each side of the coil. One side of the test light goes to ground and the other side to each side of the coil. Second test, put the test light on the side of the coil that was not "hot" in the first test and spin the motor and it should pulse.
Thanks
ANSWER: Correct, You want to know if the coil is powered and you want to know if the ignitor is grounding and ungrounding the coil.
The coil is a transformer and is powered by the battery. For the coil to build a charge sufficient to make a spark it must be grounded by either a set of points or an ignitor of some sort, then when the ground is removed by a set of points opening or by an ignitor, then the field charge is transferred to a secondary winding in the coil and that charge is what jumps the gap in a spark plug.
Howard
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QUESTION: Howard, I am still fighting the no spark. My 80B has the CEI distributor with the external amplifier and can not get a spark to the plugs. I installed new cap, rotor and wires but still get no spark from coil. I tested the coil by putting a test lamp to the + side of the coil with the ignition on and got power. Next I put the test lamp on - side and cranked the engine. All I got was a steady light, no blinking light which I think means that the coil is not switching. I opened up the amplifer and had the module tested and it is good. With all the wires unplugged, I get 0.00 ohms going from the + side to the - side. From the center of the coil to the + side i get about 4.5K ohms. I'm thinking the coil is bad and not switching. Any ideas?
AnswerRichard, the coil does not do the switching, it is just as it's name. It is a coil, actually it is two coils close to each other. The primary windings (+ to -) posts is the primary and you should either have about 1.5 ohms (if it uses a external resistor) or it should be about 2.5 ohms (if it is a straight 12v coil) If you got no connection between the + and - post,the coil is bad,but when you say 0.00 ohms you are saying there is a direct connection between + and -. That too is a bad coil. That would give you a "No switching" test at the (-) post.
I don't have any info on your CEI ignition system but what ever it uses in the dist. to switch the amplifier, should switch the coil on and off.
If the reluctor (on the dist shaft) is just a four point metal piece then you need to check the "air gap" between it and the "Pick-up".
If there are only two wires going from the "Pick-up" to the amplifier, than the pick-up is just a coil of wire and can also be checked with an ohm meter.
If the "Reluctor" on the shaft is a drum with slits cut into it, then it is a LED light and the slits and the two opposing lens need to be cleaned.
Let me know,
Howard
If the "Pick-up" is the amplifier, then you still need to check the air gap.
