Ign. coil pack's secondary ALL reading high?? | Ford Explorer Forums - Serious Explorations

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Ign. coil pack's secondary ALL reading high??


February 11, 2004
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City, State
Year, Model & Trim Level
'96 E.B. 5.0
(this is a branch off of the thread "Engine Misses/bucks under load. No codes")

i suspect possible weak coil packs so i tested the resistance, here is what i found:

primary on both packs should be 0.3 - 1.0 ohms
all mine read 1.1 ohms (a little high, but perhaps DVOM error)

secondary on the packs should be 6.5 - 11.5 kohms
mine read 13.91, 13.76, 13.72,13.62 kohms

well, they all read about 2300 ohms high...i remember another member replacing his packs with the same readings only to find that his new packs carried the same consistant high readings.

my DVOM is a craftsman digital (fairly nice) and i don't think it has that much error in it as it does register zero ohms when the leads are crossed.

what do yall think? i am going to stop by autozone in the a.m. and check their WELL's coils resistance to see if they are consistant with my DVOM.

any suggestions/advice? or WELL's vs. ACCEL?

thanks for the thoughts.

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Have you checked your wires, most of the time if my vehicle is missing it has been related to wires or plugs. If the coil isn't producing enough spark they will hardly run, if at all. I have purchased new wires and found them to be faulty, they will carry spark but it is delayed and causes misfire.

Consistancy between the coils is more important. Resistance readings in the one ohm range are very hard to make. Most low cost meters have an error of about 1/2 ohm. Other that a general check for a catastrophic failure, resistance readins on a coil are about useless.

tough to diagnose then...

yes, the wires and plugs are fairly new and as said in the other thread, were first replace to try to correct the problem.

Opera House,
great, i was afraid of that. it looks like there is no real way to be able to "test" the health of those coil packs besides replacing them.

unless yall know of some other test equipment to do so?

better question

this might be a better question...

has anyone ever found a weak coil by doing any tests with a DVOM?

I agree with Opera. My 97 5.0 received new coil packs last year when there was more inconsistency between the various readings. Before you start spending on new parts (although the Accel coil packs work quite well) I would once again carefully look at plugs and wires. Seems the heat affects the boots and arc can occur resulting in misfire. Have you checked for or added any dielectric grease to the boots? Still have the boot protectors in place? Possibility of cracks in the ceramic surrounding the plug cathode?

i've heard a few of you talking about the Accel coil packs for your 5.0's does AZ also carry them for the OHV 4.0 any know? i'm calling them in the morning, but am curious at this minute, would like to know, thanks,

cause ihave new plugs, wires, plenty of dielectric grease on them am going to do O2sensors this weekend, and coil packs, if they help reguardless is they are the problem or not.

well i do grease my boots and i am super paranoid about using the heat shields on the plug wires...however, i will admit, i did not pull my plugs out again and really check them over. i replaced them after the problem had started for several months and the new plug and wire set made no difference at all. i have since put another plug set on since one of the plug wires ripped off the boot.

so i doubt it was the plugs, and if it is now, there is still something else adding to the problem.

as far as az having a accel coil pack for the v6...not sure, go to their website and it will tell you if they have it or not. price too. a lot better than calling in the store sometimes!

thanks, i think i may order the coils (1 in stock ugh) tomorrow and test their resistance while i am there. if nothing else, i can at least narrow down the list of possible components.

tanhokie, I was probably the one you were reading about with the various other test numbers on my coil. I was getting about the same numbers you are, but I was getting about 1.3 on the Primaries.

In any case, I went and got a cheapy Borg Warner Coil from Pep Boys for testing. When I tested it, I was getting 1.1 ohms across all the primaries and 11.6k ohms across the secondaries. The one's in my car were 1.3 for primaries and 13.6k for the secondaries.

I replaced the Coils with the Accels for the 5.0 and all is better (although now it appears that my plugs need to be replaced, running Bosch wasn't a problem with bad coils, but now it is, hehe).

As for whether Accel makes them for the 4.0's, I don't believe they do. You can check, but I've never seen a 6 tower aftermarket coil before.

Good luck.

well i went to autozone and checked their coil's resistance with my DVOM...just to see. sure enough, it was reading around 13.62 kohms for the secondary and around 1.1 for the primary.

same as mine. i hate just swapping new coils in, especially since they have to order another one (on 1 in stock) but i am running out of ideas.

i have been thinking about the fuel filter. it is a "life of the vehicle" filter but i wondered if it could have gotten clogged so bad....but wouldn't it run strange during other conditions?

i also wonder about the fuel injectors. how bad is it to pull one out, inspect, and reseat? i am mainly concerned about the reseating of the gasket, but have never done one before.


pretty sure everytime u pull an injector u need to replace the o-ring , at least thats what i read when i was doing working on my nissan 240, cause i pulled those a lot till i figured out which one was broken, then i just replaced all injectors anywayz, the o-rings are kinda a pain, cause only the dealer usually has them and of course they like to make money. good luck, hope i can figure out my surging problem this weekend.

yep, with more thought, i have marked off the injectors a a possible problem.

i am going to relook the wires and plugs. with so many stories about one set of wire not working, but then another working, i do have to question if maybe it is in the connections.

i dunno, i am reaching for whatever i can get here without sinking 90 bucks for coils that may not even affect the problem.

Just wondering if you found your problem?