My Dad owns a 2001 F-150 with the 4.6 with about 150,000 miles on it. He has taken very good care of the truck and kept up on the maintenance. The truck has burnt no less than 12 coils since he has owned it. Sometimes it burns a coil on the same cylinder back to back. (this has happened at least twice) Most of the time, depending on how long he has had to run it on 7 cylinders, he would change the spark plug along with the coil. If the coil is dead, my code reader will tell us which one to change but without a CEL, its a guessing game for us. We even tried dealer parts rather than aftermarket and it still burns them. The frustrating thing is that he also owns a 2002 that is almost identical with about the same mileage and that truck has only burnt one coil. I have a Ford Escape with 160,000 miles that has the same COP design as his pick upand I have only gone through 3 coils. To me, there must be an underlying reason why this truck has gone through so many coils. Any suggestions??

 

This will be more general discussion on coils.
They live in a very harsh environment at their locations.
They get heat from the radiator/AC while the motor is running as well as the heads.
After shutdown in a closed engine bay, the exhaust manifolds and heat from the engine all combine to boost temperature very high for about 5 minute after shutdown.
This causes the coil windings to expand then slowly cool and coil size reduction.
This repeated cycling can cause broken leads at the coil terminals as well as shorted turns within the coil winding.
It is often a matter of luck for how long a coil will last as production tolerances vary.
On you short term coil life, investigate the fan clutch operation for fault, thermostat allowing the motor to run too hot, partial radiator blockage, and any other possible cause of engine temperature increases.
Other related items are to never run with one cylinder out because the raw gas will pass to the cats and cause them to run at temperatures well over 1000 degrees by igniting the gas that can cause them to melt the substrate and even block exhaust flow.
The blockage then causes the exhaust manifold to run at higher temps., creates a loss of engine power from excess back pressure plus general over heating.
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Misfire without a code:
This is a coil with shorted turns. the system does not consider this fault a hard failure but does record the misfire in separate memory.
Reason is the hard fault will cause a code so you know which cylinder is at fault.
A shorted turns condition show as misfire under certain conditions then clears until the next time. This causes the normal misfire count to be cancelled but still recorded in another memory location.
To access this location a Scanner capable of accessing mode 6, test 53 will allow you to view these misfire monitor counts in Hexadecimal notation.
The cylinder with the 'high' count is your misfire.
Bottom line is to investigate any high temperature running condition causes to help reduce the coils living environment temperatures.
Motor craft coils likely have the longest life and the greatest history of time in production dating from as far back as the mid 90s.
.
Additionally, I run a fan cooled transmission cooler that is temperature sensed at the radiator line input and thermostat set to about 190 degrees.
This ensures the engine bay never rises above about 220 area after shut down in average summer temperatures and still cools the trans cooler under towing conditions and low road speeds.
For example at 95 degrees the fan will run an average of about 5 to 7 minutes after shutdown to provide air circulation in the engine bay limiting temperatures in the bay.
At 233,000 miles I have had very little rubber part faults and reduced coil loss over the long mileage.
Can't absolutely prove the relationship but it looks like there is a link between temperature and faults.
Hope you get something out of all this that helps down the road in time.
Good luck..

 

The truck doesn't seem to run any hotter than his other one. I was hoping that someone would tell me that the problem could be a faulty computer or something of that nature.

 

What brand of coil?

 

Most of them are from CarQuest as that is the closest parts store. He did buy some junk on the Internet once a few years ago but those are long gone. He got two of them that I know of from the dealer. It had three weak coils at the same time and we almost had to tow it. (31 miles to the closest dealer) He had one CarQuest coil in his glove box and they put two Ford coils in. At the time, none of the local mechanics had a scan tool that would pick up the weak coils. The truck does not seem to discriminate with brands, it burns them all. The one that I took out today was cracked, had a hole melted in the top and oozed the side out in two places.

 

Dan, the truck needs to have a complete set of new Motorcraft coils as a new base line.
Also the coil drivers in the computer need to have all 8 tested for low resistance to be sure there is no damage to the computer from the past gyrations with all the coil used or you will lose any coil installed that will not be the fault of the coil/s
It is a shame no one services with a good Scanner or knows how to use one and just runs with codes only.
These are computer controlled engines and cannot be taken so lightly.
The issues with this truck unfortunately has caught up with the owner and now it's pay time or the issues will continue until things are done correctly and all sorted out.
I know it sounds a bit harsh but now reality has to be dealt with if it is to be resolved.
Good luck.

 

So, loosely translated, we should take the truck to the dealer and have the coil drivers tested?

 

Another possible reason? If the engine is wearing out (rings) and the spark plugs are getting a bit of oil on them. this will make the coil work harder to fire the plug and subsequently go though more coils. I think they could have done better over the years in the design of these coils. They are making a good deal of money selling new ones. With over 205,000 on mine, coil replacement has become more common.

 

Loosely translated, the job has to be done right.
I have 233,000 and have no coil issues in the last 100,000 miles.
No coil is guaranteed to last forever even Motorcraft units.
When coils short or cause issues 'repeatedly' it becomes a detriment to the PCM after awhile because the drivers has to flow the current consumed and can burn the device and or circuit board.
This is why part of your diagnostic should be testing the coil drivers to be sure.
There are two ways to do it. With a meter check and/or a scope to look a the wave forms and see the obvious issue if it is there..


If the shop is not up to it, that's another matter.
Good luck.

 

Thanks for the information. As none of our local shops seem to be capable, we will call the dealer and see if they will test the coil drivers for us and will go from there.

 

Many strange electrical issues are often traced back to poor grounding or loose connections. Grind all of the main block, firewall, and frame connections (and any ignition related components or connections) down to clean, bright shiny bare metal and cover with grease or NO-OX. Tighten securely.