Test coil

[KSmith]

1975 GL The 3 and 4 cylinders were not firing. I bench the coil primary and both coils showed 2.7 ohms. The secondary test did not have any reading when I put the test probes on both spark plug wires ends. Did I do something wrong. I know one of the coils was work fine.

[gltriker]

14,250 ohms is secondary resistance specification without the spark plug caps installed

[KSmith]

Thank you for the quick response! What is your method of testing the secondary coil? I thought you were supposed to test it by the ends of the spark plug wires without the cap on. But I had zero ohm showing like there was nothing there.

[gltriker]

https://www.randakksblog.com/coil-testi ... t-options/

[KSmith]

Thank you for your help,
The two primary both read 2.8
Spark Plug wires with out the plug caps off the end of the wire measured for wire 1&2 14.8 wires 3 & 4 14.7
All 4 Plug Caps measured different. 1 = 29, 2 = 5, 3 = 14.7 & 4 = 14.3

I believe the coils and the wires are good. I seems like the plug caps were old. I ordered a new set of plug caps.

[gltriker]

You are very welcome

[redglbx]

FYI,, the plug caps should read less than 5k ohms when measured across them .

[KSmith]

Thanks for the feed back. I am not a train mechanic and electrical issues could be such a challenge. But with the help in following the procedure step-by-step, I was able to figure out that the caps were failing.
Today I’ll put the coils back in and clean everything up and wait for my caps to come in the mail.
Thanks again

[KSmith]

I put the coils back in, installed the new spark plug caps and started up the engine. Again cylinders 3 and 4 were not firing.
I believe it must be the coil. I have an additional question. When I rebuilt the GL in 2012 I put in a Dyna ignition and never had any issues!
Now looking at coils there is a large price span.
Dynateck on e bay for a pair is $200.00
SLMOTO $23 for one each.
Has anyone use the low end coils and did you have fitment and or performance problems.

[gltriker]

I put the coils back in, installed the new spark plug caps and started up the engine. Again cylinders 3 and 4 were not firing.
I believe it must be the coil. I have an additional question. When I rebuilt the GL in 2012 I put in a Dyna ignition and never had any issues!
Now looking at coils there is a large price span.
Dynateck on e bay for a pair is $200.00
SLMOTO $23 for one each.
Has anyone use the low end coils and did you have fitment and or performance problems.

Have you seen Cedric's low end ignition coils installation document?
viewtopic.php?t=77232

[gltriker]

I put the coils back in, installed the new spark plug caps and started up the engine. Again cylinders 3 and 4 were not firing.
I believe it must be the coil. I have an additional question. When I rebuilt the GL in 2012 I put in a Dyna ignition and never had any issues!
Now looking at coils there is a large price span.
Dynateck on e bay for a pair is $200.00
SLMOTO $23 for one each.
Has anyone use the low end coils and did you have fitment and or performance problems.

Ok. Upon reading that you have verified the problematic ignition coil primary and secondary windings resistance are both within specs and you have installed new spark plug caps, but still have cylinders 3 and 4 "not firing" let's look elsewhere.

I noted you have an additional question.
Me, too!
Have you verified the complementing Dyna ignition module, itself, that controls the ground side of the primary windings in the #3 and 4 cylinders' ignition coil is working, correctly?

A quick dynamic test is this. Go to where the 2 primary leads from the Dyna ignition, each, plug into their own assigned double socket terminals under the 'rubber umbrella'. Unplug both Dyna primary leads there and switch their connections into the other's double socket terminals. You are testing whether the suspected fault follows a truly problematic #3 and 4 ignition coil.

*You may possibly discover the DynaS blue wires bullet terminals connection was loose and unplugged under the 'rubber umbrella' *

VERY IMPORTANT!! You MUST swap positions of the #1 and #3 spark plug wires on the right-side cylinder head * AND * swap positions of the #2 and #4 spark plug wires on the left-side cylinder head BEFORE attempting to start the engine.

If you don't swap the spark plug wires as directed, before cranking the engine, there will be loud BANGS leaving the muffler outlets

If the suspect 3-4 coil does 'fire' the cylinders' 1 and 2 spark plugs, but the 1-2 coil doesn't 'fire' cylinders 3 and 4 spark plugs, you will then continue troubleshooting a primary ignition wiring circuit fault with your multimeter. ( coupled with a multi-meter, a 12volts probe tester with a low watts bulb is a valuable diagnostic tool, too )

Report back


IF the Dyna S(?) is discovered to be faulty, Cedric has another document to address that problem, as well

viewtopic.php?t=77231

I May as well attach a very useful link to 3 Dynatek ignition documents here, too

https://ngwclub.com/forum/viewtopic.php?t=78099

[KSmith]

I switched the two wires under the umbrella and switched the spark plug wires as directed. When I started up the engine cylinder three and four still no fire in the hole.
Please, what are the next steps?
Thank you for your help

[gltriker]

I switched the two wires under the umbrella and switched the spark plug wires as directed. When I started up the engine cylinder three and four still no fire in the hole.
Please, what are the next steps?
Thank you for your help

see my Private message first

[KSmith]

Today I received in the mail, my two magnet dual output coils with wire and hardware. Once I get them installed I will give an updated.

[gltriker]

Here's my solution to alleviate air filter housing snorkel contact interference with the upper right-hand sparkplug wire.
Significantly eases reinstallation of the air filter housing onto the carbs rack, too
https://ngwclub.com/forum/viewtopic.php ... 56#p819956

AND when the ballast resistor is removed, simply connect together its 2 unplugged wires' bullet terminals

20190604_172843_resized_1.jpg