1994 Ford Explorer - Coil Pack Testing

I go over how to test the coil pack on the 4.0L OHV Cologne engine in the Ford 1991-1994 Explorer. This method also applies to a lot of other Fords.

[@chickennugget6985]

Good video... And your resistance checks were well noted and explained too.

[@kurthamblin1240]

This was a great video buddy keep it up

[@gmanNC13]

Awesome walk-through. Thank you for saving me money!

[@HsCSpanky]

Glade Mellor you're most welcome, glad I could help!

[@77goofyguy]

Thanks for posting this

[@keithreiffenstein9909]

I had mine off and checked it..it checked good....so I turned the oven on @ 200 degrees and put the coil in there for about 30 mins...checked again and the center two were dead..along with the corresponding pin.... I had a problem where after I ran the explorer and restarted it had a miss..checked plugs all looked fine..next time I drove it it was fine until I restarted it missing again...Coil was OEM with 347,000 miles..1991 Explorer 4x4..

[@HsCSpanky]

Good on you for testing a hot soak, that's a good idea!

[@jnhook8086]

Thanks for the info. Just an FYI, I noticed the screw on the left side of the coil pack (in perspective) was loose

[@montereymilitia5184]

Also the primary coil is the first windings and the secondary is a longer set of insulated wiring. It’s too complicated to just explain but it has to do a magnetic field and taking your 12 volts to building to up to thousands of bolts to enable it to bridge a gap and be hot enough to ignite fuel. Look it up. It’s interesting.

[@WillieMakeit]

great idea on them T pins

[@montereymilitia5184]

Good video. Helped. Just a small correction though. It works like a old Harley. The spark doesn’t come back through another plug. It fires both at the same time. The reason is cause it’s cheap and easy. The two are on exact opposite strokes so the spark on the other would be near tdc but not on the compression stroke. Just like you have to be careful when putting your motor to tdc that your on cylinder ones compression stroke and not the other cylinder reaching the top of its exhaust stroke.

[@user-hk5ji5ws9d]

Also Cool Video very Helpful ( Thank You )

[@andykinard6186]

Interesting explanation of how the waste spark system operates. Let me see if I've got this right, the spark pulse fires from one tower of a particular single coil, travels through the corresponding spark plug wire to the spark plug of the corresponding cylinder. The pulse travels through the center electrode of this spark plug to the ground electrode thus creating the 'spark'. The 'spark' pulse then travels from this ground electrode through the threaded metal casing of the plug into the engine block (which the plug is threaded into) through the block to the casing of the cylinder corresponding with the opposite tower of the same coil, across the ground electrode of this plug to the center electrode of this plug. The pulse then travels up the center of this plug to the attached spark plug wire, through this wire to the cool tower opposite of the tower where the pulse originated and into the original coil thus completing the circuit. Is this correct? In 38 years as a mechanic, more than 30 of which certified as a Master Technician in multile areas, I have never heard this phenomenon. You are totally correct up to the point if the spark crossing the engine block to another spark plug and back to the coil. It is here that you are leading others astray. The high voltage electrical impulse from the coil terminates at the air gap between the center electrode of the spark plug and the ground electrode of that plug. The spark is created by the electrical arc between the two electrodes of the individual spark plugs and goes no further. The 'waste spark' concept derives from the fact that BOTH coil towers of a single coil in the pack are energized at the same time creating sparks in both of the corresponding cylinders at the same time. One cylinder is at the end of the compression stroke and the air/fuel mixture is ignited while the corresponding cylinder of the same coil is on the exhaust stroke. This reaults in the spark inside of the cylinder on the exhaust stroke being 'wasted' as there is no unburned air/fuel mixture to ignite. Other than this little error you have put forth a very informative and easy to understand video that should help many people. Well done sir!

[@taylornordquist6268]

Thank you so much

[@Arcturian1111]

Question. On 2 of my spark plug wire clips that clip into that block /, aren't tightly clipped. Is this normal? Block and wires are all good. It just doesn't clip in perfectly.

[@JohnWernerful]

Very nice vid. very helpful! thanx!

[@HsCSpanky]

I'm glad it helped :)

[@ryandenny2955]

Great video but I do have a question! I'm testing this on my 2002 vw jetta and I dont get any readings for my secondary coils at all and I only get readings of 1.3 when I change my dial to 200m for resistance...does this mean my coils are shot?

[@HsCSpanky]

VW are in their own world. Normally I'd say yes but if all of your coils read that way, I'd think something is up with the testing method or with the equipment. A quick look shows .5 to .7 on the primary and 3k-4k on secondary. If all of yours are dead, I'd wonder if your engine severely overheated or if the computer fried them. Both are unlikely which is why I think the testing or test equipment is wrong. Make sure you have fresh batteries and good connections on your leads (check a spark plug's resistance from center tip to where the boot attaches).

[@SKIFcccp]

thx !!!

[@beautiFUlLadY4u]

hey i have a .1 on my primary side what dose this mean

[@509wsdaddy7]

Okay so I did exactly what you did in the video and for some reason I'm not getting spark to my plug but my coil primary and secondary testing showed good where do I go from here

[@HsCSpanky]

David ws509daddy Koch is the wire good? After that I'd either opt for a junkyard could or hook a test light up as a dummy load to the coil inputs.

[@austinealy7349]

My primary is .29 does this mean it’s bad?

[@georgeturner9678]

I own a 1996 ford ranger 4.0 2x4. Auto..with an intermittant no start. Took it to a shop who claimed not to have a code. They changed the crankshaft sensor and it ran for a day. Now it wont start. Did the secondary test. And got 19.7 ohms on the all the coil pairs. My last two culprits may be rhe ignition key or the ignition module...which someone told me that my 1996 ford ranger does not have. Any recommendations would be greatly appreciated.

[@tiffanygould6939]

sounds like a bad conecctions i saw a video or post on a rangerforum about something similiar check all fuses and relays and the conecctions to all to be sure i think the vid was on here somewhere

[@atxjax1]

I have a 1999 ranger 3.0L. My primary resistances all check out good but all 3 of the secondaries read open. I tested just like you show in your video. Safe to assume bad coil? I am getting hesistation and P0305 on my truck,

[@HsCSpanky]

Looks to me like it's pretty much an identical coil pack. Make triple sure of your multimeter setting, they're different scales. You have to switch from 200 ohm scale to 2k ohm scale. Usually it's just 1 or 2 coils that go bad, I'd be suspicious if all 3 died at once. But if you're 100% sure that all 3 secondary coils are open then it probably needs replacing. I'd be curious to see if you crank the ohm scale way up if they read into the mega ohm range? I had a spark plug wire do that, it wasn't open but just extremely high resistance. That 1 plug wire being dead made the engine feel like it was going to die at a stop sign.

[@atxjax1]

I have a pretty nice Digital Fluke meter with auto ranging. I tried it with the auto range on. Then moved it into the ohms, K ohms then M ohms scale and all read open. I though I was testing wrong but I don't know. I get nothing on secondaries.

[@HsCSpanky]

Make sure the battery is charged on the meter? I've had bad readings from that. I'm just suspicious because the engine runs and yet all 3 are open, that doesn't compute. Did you check the reading hot and cold?

[@atxjax1]

My meter is new out of the package with a new battery. Readings were taken with truck cooled off a bit. Im thrown off too. There should be some type of reading. So the coils just test one directly across from the other like you did in your video correct?

[@HsCSpanky]

Yea, that's the only way they go. 3 pairs of them. Try the coils when the engine is hot. If I were you, I'd try to find a junkyard coil pack or one off of eBay to test before buying a brand new one.

[@montereymilitia5184]

They call it a waste due to the fact that the other spark created is wasted because it’s not igniting your air fuel and does nothing.

[@wtzszombiesprod.3666]

I've got a 1995 ford explorer. Bought it for 250$ after not being able to afford a vehicle (mind you im 17) and it runs...like garbage when I'm driving. It'll start to studder and I'm almost positive it's the coil pack on it. Think I should break down and buy a new coil pack with cables or just a coil pack? And am I able to drive it just for now until I can get it? It's crazy just need a little help. Thanks

[@HsCSpanky]

Only replace it if it fails as in this test. I believe the 1995 has the same coil and the test will apply. Also test the wires, they will probably be in the 2-6k ohm range. If one is 500k or infinite, then you know it's a problem and can replace it. It's important to know why you're replacing things, especially when you're on a budget. If the truck is running rough like it's not firing on all cylinders, I wouldn't drive it. It will mess with the exhaust and burn lots of gas. The engine computer sees the unburned oxygen in the exhaust and adds more fuel to compensate. Look at my other videos and perform a KOEO and KOER (should apply to your Explorer too).

[@rafaellozano5552]

i do that thanks

[@Harlinization]

Hey Nate - have an Explorer Eddie Bauer 4.0 V6 - the car sat for a while a year or so got it back up and running but now i have a misfire - have tested the coil pack all my readings seem to be within the ratings you listed in the video - what other tests can i run to get the car running smooth again.

[@HsCSpanky]

KOEO and KOER tests, I have videos about that as well.

[@Harlinization]

@@HsCSpanky Forgot to mention its a 1997 - it has an ODBII port and the error codes are as follows P0102 - air flow sensor P0303 - misfire 3 P0305 - misfire 5 P0171 - fuel system too lean bank 1 P0174 - fuel system too lean bank 2 P1131 - lack of upstream oxygen sensor P0172 - system bank 1 too rich

[@HsCSpanky]

@@Harlinization clean the maf or unplug and see if it runs better. Definitely test spark plug wires (ohm test) and check the plugs. If that's all good, I'd be worried about fuel injectors not holding pressure or working right. Would be worthwhile hooking up a pressure gauge to see what's going on, if it leaks down or gas low pressure.

[@Harlinization]

​@@HsCSpanky​ Cleaned the MAF but that did not seem to have any effect (will try to unplug it) Tested the Spark plug wires and the readings where [ 1 - 6700ohms ] [ 2 - 6360ohms ] [ 3 - 7220ohms ] [ 4 - 13800ohms ] [ 5 - 13200ohms ] [ 6 - 12510ohms ] When you mention preasure gauge I assume you are referring to Fuel pressure and testing using the valve under the Air intake ? its also tossing out Blue-ish smoke

[@HsCSpanky]

@@Harlinization blue in exhaust is oil, no doubt. Yes, check fuel pressure. If you see black smoke, try to avoid running it, it will fry the catalytic converter. Wires sound good. Plugs are probably ok. I'd lean towards fuel injector issue. You could try a heavy dose of injector cleaner or seafoam.

[@rafaellozano5552]

i have a ford rager 2011 2.3 engine stalls when i put it on gear and i notice its burning gas like crazy i can almost see the gage go down it used 1/4 of the tank in about 40 miles. any opinions? i do want to point out i had never own a ford in my life so i know absolutely nothing about this trucks

[@HsCSpanky]

Sounds like multiple issues but stalling when putting into gear can be the idle air control valve. Also running rich but that can be all kinds of things. I can't help much, yours is a different system than mine that I'm not familiar with. Start by getting engine codes and work from there.

[@tiffanygould6939]

am doing a project with a coil from a ranger with a vertical plug and was wondering if u knew witch wire was the wire from the ecm that tells it to fire its a 2000 ranger with a 3.o if u could let me know much appreciated

[@HsCSpanky]

Off of the top of my head and not knowing how a 2000 ranger is set up, there's four wires. I could be wrong but I believe there's one power wire in that should be red and it should be a larger than the rest. The last three wires should be the ground for each set of coils. If you supply power in ground, then remove the ground it should spark the secondary coil.

[@tiffanygould6939]

@@HsCSpanky thank u very much

[@beautiFUlLadY4u]

is that a good read for that side the secondary coils showing 13.5 13.30 13.15

[@HsCSpanky]

As long as they're all close, it's fine. They might vary from mine due to changes over the years. It's unlikely for all the coils to fail, if one of yours was 50, that would be a problem.

[@macknumber9]

Would it be a good idea to try to test it after going for an aggressive drive to get it really hot then immediately tsst it

[@HsCSpanky]

Wouldn't hurt to have a cold and hot reading.

[@macknumber9]

@@HsCSpanky cold 11.4 hot 12.0 These numbers look good?

[@HsCSpanky]

@@macknumber9 are they all similar? That's not much of a change so I'd say it's good.

[@macknumber9]

@@HsCSpanky yes seems like they all are similar

[@caseyostrander503]

Hey, man. Thanks for the great DIY! I used it with high success on my ’92 Ranger 4.0. The only discrepancy I noticed is that my primaries read a consistent 1.2, rather than the noted spec of .3 - .9. I’ve read on one of the Ranger forums that .5 - 1.5 is acceptable on coil packs, while the .3 - .9 applies to single ignition coils. Any thoughts on this? Again, thanks for a great walkthrough!!!

[@HsCSpanky]

Casey Ostrander Thanks, I'm glad it helped. I think 1.2 is fine. It's such a small difference and Ford probably revised it. Higher ohms means less power consumption. If you were getting 5 to 10 ohms, I'd say there's a problem. The secondary circuit is more picky with shorts than the primary anyway since it's much higher voltage and can jump through cracks.

[@caseyostrander503]

Thanks again, Nate! Very much appreciated!

[@caseyostrander503]

Just an update: Turned out I had a bad fuel injector in cylinder 5. Replaced it and the truck runs great! So glad I found this video, because until I tested it, I was all ready to replace the coil pack, which would have cost me, without any immediate benefit. You rock!

[@HsCSpanky]

Casey Ostrander awesome. How did you find that out?

[@caseyostrander503]

I had priced them out at about 70 bucks a pop at my local parts store, then found a set of rebuilt (and upgraded) Bosch injectors on eBay for $100. I watched them for a few days on and off while I tested other things (because I was nervous about buying rebuilds), then the price dropped to $67 for the last set that the seller had. At that price, I had to buy them, even just to keep as a backup. Popped them in, replaced the plenum gaskets while I was in there and voila! Runs like a champ now.

[@Robert-bm5fz]

i tested my secondary (2000 ranger 4.0 ohv) and got 8.3 on all of them equally. truck is running rough but i see a lot of spark at the plugs. any ideas as to why they are all the same?

[@HsCSpanky]

You should get vastly different results on primary vs secondary coils. But you do want the coils to all be the same in their circuit.

[@Robert-bm5fz]

@@HsCSpanky if primary being the plug pins and secondary being the top where the plug wires go, i stopped testing afyter the secondary failed but checked and had plenty of spark and the readings were all the same. am i understanding you when you say primary being the 4 pin plug?

[@HsCSpanky]

@@Robert-bm5fz If the secondary failed the test shown in the diagram at 2:28, then your coil pack is bad. It may still produce spark on one side or a weak spark but it may not be enough to jump the 2 plugs together. The primary is the 4-pin coming from the ICM and the secondary is the spark plug wires. Check out the image at 2:28 and make sure to follow the AA, BB, CC and 11, 22, 33 numbering closely.

[@Robert-bm5fz]

@@HsCSpanky yep i did and you are right its a no go. thanks for the help clarifying and thanks for the video. it was extremely helpful.

[@Robert-bm5fz]

@@HsCSpanky it is odd that i am getting a lower resistance though (8.3). kind of a mystery to me.

[@samisosa8989]

what if primary more than.3-.9 ohm, its showing 1.2 ?

[@HsCSpanky]

sami sosa that's fine. If it was 50 or 2,000 then you know there would be a problem. Ford might have changed the spec slightly.

[@samisosa8989]

ya, its same like 96 ranger 3.0.Ok thanks, Also, how do check, Camshaft Synchronizer? i have under 8 voltage goin thru the wire.

[@samisosa8989]

and i dont have the sparks

[@HsCSpanky]

Since I only have the books for the 1991 Explorer/Ranger/Aerostar, I don't have any diagnostic info on the camshaft sensor since that year didn't have it. Sorry.

[@samisosa8989]

appreciated for your help

[@joetonia1367]

I have changed everything , the coil pack , the icm, the crank sensor , and still no spark , this all happened after changing my serpentine belt ,

[@HsCSpanky]

Being that you were in the front of the engine, I'd wonder if your wiring to the crank sensor got damaged. That's about the only thing it could be.

[@NewYorkCityBoxing]

Same issue with my Ranger. I changed the belt and cruise control buttons and now I have no spark or lights.

[@jcpeagler5190]

KZbinr how to change a tire on a Ford how to change the time on a Ford Explorer XLT 9 4

[@dongking6245]

Cam positioning sensor or knock sensor ?

[@terrychapman9195]

Probably just it in no ok

[@magicyeti9256]

Delete T-pin.