Ford ignition coil (waste spark) testing with a multimeter. Mustang, Windstar, Freestar 3.8 / 3.9 V6

Ford waste spark ignition coil testing
Resistance for DG-532 Motorcraft coil
Same with OE replace coils
0.3-1.0 ohms - primary winding
6.5-11.5 Kohms - secondary winding
Always check for cracks, corrosion, and it's best to check ignition coils still on the vehicle fully warmed because heat soak can cause a higher resistance reading. This can cause a weak spark output and cause misfires and lean fuel trims.
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[@charlesforte6473]

Well Done , Excellent Video ! Thank you Sir !

[@SkylerVahidy]

Thanks for this! I was reading 1.4 on one primary and .06 on the other

[@singularautomotive3542]

No problem, glad it helped!

[@macknumber9]

All 3 should be dead on? Is that important? I measured .8 on two and 1 was .4

[@singularautomotive3542]

Specification says 0.3-1.0 Ohms is an acceptable primary resistance according to Ford. Most of the ones I've checked usually read 0.6-0.9. Had one read 1.2 and was having a weak spark problem out of it. You should be alright with one reading 0.4 and the others at 0.8. Did your secondary look good? Did you test it with the engine bay hot or cold? And are you having ignition problems and if so, what's going on?

[@macknumber9]

@@singularautomotive3542 I don't know if I have ignition issue or not but I have a slight misfire shaking st idle....I'm going to check secondary right now and get back to you....I'm going to check it cold and then I'm gonna let the car warm up and check it hot...

[@ShakeelKhan-px1fl]

Hi my friend my ignition coil is doing 1.9 om primary and 12 om om secondary is it bad ?

[@lumoralesx]

so helpful, thanks

[@macknumber9]

I'm confused on the relationship between the MAF and the ignition process. How does the MAF have anything to do with the ignition....

[@singularautomotive3542]

The MAF calculates how much fuel is needed to match the amount of air or air mass being consumed by the engine. O2 sensors make this even more precise but most O2 sensors need to warm up first. The camshaft position sensor actually helps to time the fuel injectors pulse rate and the crankshaft position sensor's main responsibility is to report engine rpm and relay this info to the pcm, the pcm can then time the spark based off top dead center of the piston stroke. I've noticed most vehicles, especially maf only cars will go into a default strategy provided by the pcm if the MAF is unplugged. They may start but run very poorly because they cannot mix the fuel/air correctly. 02 sensors let the pcm know how much oxygen remains after combustion has occurred and helps the pcm adjust to keep the fuel mix from becoming to lean or rich. Hope this helps

[@macknumber9]

@@singularautomotive3542 that does help. Thanx for the response. Your answer actually helped in another way. You bring up the point of o2 sensors and how they need to be warmed up. I am having an issue with rough idle and what feels like misfires (shaking floorpan) at idle when I first start up or when I am in park or neutral) it is worse when it first starts up though....I cleaned MAF sensor last night although it didn't look dirty at all and I can't believe the difference it actually made. On my scan tool live data it sits more stable (maf data airflow rate) and it idles perfect as long as the car is in gear (under load). I wonder what direction I should go to in diagnosing the issue of shaking upon start up and worse idle out of gear (park/neutral)....fuel trim doubles when I go from drive to park idling....somewhere around 3% long term up to 6% long term but it happens immediately upon going from drive to park and if I go back to drive it evens out and goes right back to +2%....I wonder if I could have a very small vaccuum leak or if this could be an issue with a dirty clogged fuel injector

[@singularautomotive3542]

@@macknumber9 I would definitely try to check for a vacuum leak, you said shaking floorpan and that makes me think more of a small exhaust leak which would alter your fuel trims too. I'm assuming you have a Ford, if your scan tool has Mode $06 capabilities or a non continuous monitor category you should be able to scan it when you're suspecting the misfires are occuring and get a reading of past and current misfires for each cycliner and more information about how your exhaust system, including the EGR is functioning. A partly stuck EGR pintle and EGR vacuum tube leaks are common on Ford's and can cause roughness too

[@macknumber9]

@@singularautomotive3542 I do have a ford...3.9 v6 mustang...I bought a scan tool that has mode 6 but it is a pain to find misfires on it....I don't know the parameters for when it is even recording the misfires....it isn't in live data which I wish it was....I get like 5 misfires on a count of 1000 so I don't even think that's a concern but I don't know if it is ever even recording misfires at the time I feel them most (idle in park upon starting engine)

[@macknumber9]

@@singularautomotive3542 the shaking floorpan is only at idle in park....if I put it in drive and idle it won't do it. I don't think exhaust leak because exhaust leak it should happen all the time at idle not just in park idling.... Only thing that I can tell so far is when it idles in drive (calculated load 40%) it idles great no complains and when I throw it in park (load goes down to around 30%) and idle is little bit rough and fuel trim goes leaner....