How to test my coil to see if it's any good?

evintho · Jan 13, 2019

Testing for spark from the coil, I pull the coil wire off the dist cap and turn the car over. Sometimes there is a spark and sometimes not. Does the coil wire terminal need to be close to another piece of metal to see the spark jump or can you see it just by looking into the boot?

I'm thinking my coil may be toast. It's an original '89 Ford piece. How do you test the coil for proper operation?? I have a DVOM.

The coil in question...……………..

lmsport · Jan 14, 2019

the coil wire needs to be about 1/4 to 1/2 inch from a ground like the block

the ignition module likely also needs a good ground through the bolts loading it down, but verify with your wiring schematic

evintho · Jan 14, 2019

The terminal is sunk a full 1" inside the terminal boot. Ign module is grounded through a factory heat sink.

chasracer said:
Unless you're just testing a no start or misfire condition - you should just replace the coil and be done with it.

I have a strange 'no start' condition. After sitting for 8 hours, the car starts right up and runs fine. Once I shut it off, it won't start again. No spark at the plug wires (terminal 1/2" from plug tip). All plug wires ohmed out good. Replaced rotor and cap. Coil wire ohmed out good. Next would be the coil.

chasracer · Jan 14, 2019

Unless you're just testing a no start or misfire condition - you should just replace the coil and be done with it.

chasracer · Jan 14, 2019

Sounds like an overheating situation where the winding in the coil is expanding, breaking connection - no start. After a period of cooling down time, the connection is good again and it starts.

evintho · Jan 14, 2019

Sounds feasible. Is there any way to test it with a multimeter?

How to test my coil to see if it's any good?

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