# Help needed diagnosing multiple coil pack failures



## mitchd123 (Jul 27, 2015)

2014 LTZ 1.4L Turbo ~ 60k miles.

My original factory OEM coil pack failed around 55k miles. Two of the ports were deeply corroded. I replaced it with an aftermarket coil, and the car ran fine for about 2 months. Then one day on the highway the engine cut out and it would not start. After about 10 minutes of waiting for the tow truck, I tried it again and it started up and ran fine for a few more days. The problem started occurring more frequently until the car became undrivable. I called the company and they sent me a replacement aftermarket coil. With the "new" replacement the car would not start at all. If I put the old aftermarket in, it would start right up and run for a few minutes. I complained and the company sent me another replacement. With this third aftermarket replacement, the car started and would run forever, but the engine was skipping. (ECU 420, Traction Control, etc.). I replaced all the plugs, but the problems never went away. I moved plugs around and the skip stayed with Cyl #1, which led me to believe the coil was bad. I did a compression test and cyl #1 had good compression. I decided to buy an MSD coil and stop messing around. While waiting for the MSD to arrive, I rebuilt my original OEM coil the best I could. I cleaned out the rust on two ports and put on new boots, etc. The car started fine and ran perfectly for about 20 minutes. As soon as it heated up, it would start skipping with the old OEM coil. The next morning it ran fine again until it heated up. Finally the MSD arrived. Installed the MSD, and the car ran perfectly for 10 minutes and died. The car would not start again. I pulled the MSD out, and put in my original OEM coil and got the car home. 

What is causing all these problems with the coil packs? Is there something else that I'm missing? I refuse the believe a new MSD is bad. I've inspected the connector to the coil and it's in decent shape. What else could be causing this? I've cycled about 6 coils in and out, and can seem to get a good one? Each coil pack consistently fails in it's own unique way. Pack 1 skips, pack 2 randomly dies, pack 3 won't start, pack 4 skips, pack 5 died, etc. Out of desperation I even replaced teh original battery, which was 5 years old, but it had no impact on the problem. My only guess is the voltage going to the coil is too high or low, or the digital signal or timing is messed up. 

Any ideas?


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## plano-doug (Jul 1, 2015)

mitchd123 said:


> 2014 LTZ 1.4L Turbo ~ 60k miles.
> 
> My original factory OEM coil pack failed around 55k miles. Two of the ports were deeply corroded. I replaced it with an aftermarket coil, and the car ran fine for about 2 months.


To be clear, the new coil pack included new rubber boots and new springs?



> Any ideas?


I'm thinking wiring. Inspect very closely the connector going to the coil pack. Look at the wires going in to be sure one or more are not frayed or making poor contact. Examine the mating side of the connector to be sure the contacts make a good connection with the coil pack. Trace the wiring harness back to be sure it's not rubbing against anything which may have damaged it. Trace it back to the computer.

With that many coil packs, I'm pretty sure it's upstream of there. Most failures are wiring - the computers are pretty robust. That said, if the cable is in good shape, and the coil pack is good, then it's time to consider the computer. But look closely at the wiring first.

Doug

.


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## Robby (Mar 1, 2013)

Crank or cam position sensor is going open when hot. The coils get info from the ecu which gets its information from the sensors mentioned.
You are addressing the end of the line, not the beginning.

Rob


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## ChevyGuy (Dec 13, 2014)

I like Robby's theory, but I'll add another thing to check - spark gap. The bigger the gap, the more stress it puts on the coil as it takes a higher voltage to jump it.


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## mitchd123 (Jul 27, 2015)

ChevyGuy said:


> I like Robby's theory, but I'll add another thing to check - spark gap. The bigger the gap, the more stress it puts on the coil as it takes a higher voltage to jump it.


Thanks everyone for your suggestions. 


Yes the coils came with brand new boots
I'll give the wires another good inspection to see if I can find any wear points
plug gap - great idea, I did make sure they were gapped to .30
Camshaft sensors - will check.


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## WillL84 (Aug 5, 2019)

ChevyGuy said:


> I like Robby's theory, but I'll add another thing to check - spark gap. The bigger the gap, the more stress it puts on the coil as it takes a higher voltage to jump it.


This seems to make the most sense. Once the sensor warms it goes open and the ECU doesnt' get a reading from it. Cool back down and it's fine. I've seen this happen with ignition coils on snowmobiles and stuff over the years - runs fine for 10-20 minutes then no spark. Let it cool and it's fine again


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## Blasirl (Mar 31, 2015)

mitchd123 said:


> Thanks everyone for your suggestions.
> 
> 
> Yes the coils came with brand new boots
> ...


Same answer I posted for you before:
Tips to ensure no misfires occur because of changing the coil pack:

Remove the coil pack. If the boots are stuck on, use a small screwdriver or pick with some dielectric grease on it to go around the outside of the boot and then possibly the inside of the boot to help aid in removal.

*Remember to (p)re-gap your plugs to .028,



Set gap with the black portion of this tool.*














*Measure the gap with feeler gauges.*















*Throw this away.*
















Torque to 18 ft-lbs with no anti-seize on the threads of a stock type plug.

Ensure the boots have no rips/tears or holes in them,and make sure the resister springs are clean and not caught up in the boots when you install them. Lightly coat the boots and springs with dielectric/silicone grease.

I recommend the MSD coil pack

If the plugs look bad, consider these:

*-BKR8EIX-2668* (iridium plugs), ~$25, expect ~10-15k regaps on these, ~40-50k overall life.
*-BKR7E-4644* (nickel/copper plugs), ~$8, expect 15-25K out of these plugs, with a regap or two required at 5-8k intervals on stock tune.

Read _Hesitation Gone!_ for more info on the plugs.


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## alexeilb (Feb 26, 2011)

Camshaft sensor sounds plausible, if plugs are over gapped that would also fry your coils. I worked on a Mazda Tribute that had badly worn spark plugs to the point where they couldn't Arch as a result coils went and PCM got fried. But you said you moved the plugs around and still see the same results. Curious to learn if you found the problem.


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## lonewolf04 (May 6, 2016)

There was a TSB that pointed out failure of the connector that connects to the coil. I believe the terminals would spread and make poor contact. Unsure if that is the issue you are having, but it is documented on the OEM side.


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## Blasirl (Mar 31, 2015)

lonewolf04 said:


> There was a TSB that pointed out failure of the connector that connects to the coil. I believe the terminals would spread and make poor contact. Unsure if that is the issue you are having, but it is documented on the OEM side.


Can you post a link to this TSB?


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## lonewolf04 (May 6, 2016)

#16-NA-015: Engine Stall or Stumble - Replace Coil Connector - (Jan 21, 2016) 



https://static.nhtsa.gov/odi/tsbs/2016/MC-10112283-9999.pdf


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