Testing ignition coil 71cb500/4

[Bobby Joe]

Hey, I am using the tapatalk app and there doesn't seem to be a search function. Sorry if this has been posted already. I am decent with the mechanical drawing but I tend to get a bit mixed up with the electrical drawing/words and I wanted to double check my work with you guys.

I found a link on either here or SOHC that said there should be about 5 ohms between the primary terminals. I checked that with my multimeter set to 200 ohms (smallest available) and it came out to 5.8-6.2. This was done by touching my leads to the blue wire and the black/white wire (yellow+black/white on other coil).

The same link said the secondary coil should have a resistance of about 15k ohms. On this one, I connected almost every combo I could think of and nothing happened on my multimeter. The manual says to check for continuity to touch the probes in the end of the two spark plug wires. When I do this, the multimeter stays at 1 (aka infinity, correct?). Manual states that the coil is open and needs replacing. How would I connect the probes to measure the 15k ohm resistance? Thanks.

 

[Bobby Joe]

Additional note. I placed the ends of the spark plug wires about 1/8" apart from each other and connected the two small wires to a 12v source and I got spark for each coil. It didn't look super strong tho.

Also, that source from before days there should be about 5 ohms resistance across the primary terminals. But the manual says that you should be checking for continuity. The first would be looking for 5 ohms on the MM and the second would be looking for near 0, correct? So which is it then!!??

 

[Bobby Joe]

I connect the spark plug boots to the wires and then put a spark plug in each pair of boots. Then I touched the two corresponding plug threads together. Once they are set, I applied a 12v source to see if the spark plugs would each show a spark. Neither did. I have already trimmed the wire back 1/4" and reset the boots onto the wire. They feel much tighter too. Can the boots go bad?

 

[mydlyfkryzis]

Boots/caps definitely go bad. Mine was bad. Spark at plug when testing, but misfire when running.

On double outlet coils, the continuity on the coil is from one spark plug wire to the other, caps off. The number itself isn't as important as having neither open or shorted readings.

The secondary side should spark from one wire to the other in testing. Putting it on a plug and grounding doesn't work. The secondary side is a circuit from one plug wire to the other.

 

[Redliner]

The spark would not appear until you break the circuit.

When you measure resistance between primary and secondary, you do so with the plug boot removed. You want 10k-15kΩ. Less than that is pretty weak.

I have Dyna coils on my CL. 5ohm on the primary and 13kΩ on the secondary. Great spark!

Does sound like it's time for new coils. Any dual-output with anywhere from 3-5Ω resistance on the primary side will do fine. Mounting is the only hard part.

 

[Bobby Joe]

Thanks for the I do guys. Very clear and exactly what I needed to know/learn.

Time to shop for new coils...