Ok so when I bought my truck it had a misfire on cylinder #4, I replaced all of the motorcraft coils with MSD coils and now 1 year later the same thing happened, #4 coil failure! Is there a problem with the harness or just a coincidence? I am 2 months past my warrenty but MSD is still going to replace it.

 

Surprised the MSD's made it this far.
Check for water in the plug well

 

No water. MSD does have great service though.

 

Did you use dielectrical grease? I just replaced all mine with araparts COP's this past weekend and I heard great things from friends using them. Going on yrs with no problems. I had lots of problems with motocraft, just must have been a bad batch but try a different brand and USE dielectrical grease!!

 

Tfast. Sorry to get off subject but I have to ask. I see you have stock wheels on your 7700. What size are those tires? I gave up on looking for wheels and just want to go bigger tires but wasnt sure how they would look on stocker wheels. Yours look pretty good.

 

In my opinion, you can't beat motorcraft cops for these engines.

 

^^agreed. 2 years ago I bought 8 global cops off ebay for mine when I put new plugs in it. 2 weeks ago I just replaced my 3rd cop in that 2 years.

 

the seal on the wiper cowl has a tendancy to leak, taking out the rear two COPS



and x3 on the MSD lasting this long, I'm actually quite suprised

 

There was no grease in the #4, A mechanic buddy of mine put them in when I was working, I guess I better take them all out and grease them! Everything is build to breakdown stock or aftermarket, obviously the motorcraft ones fail aswell since I had to replace them in the first place, and I got them cheaper then from ford and I couldnt wait for ebay ones. I did not see any water in the area, but could the excess heat from the heatercore lines and no grease may have caused this? but it seems like a coincidence that both motorcraft and msd coils failed on the same cylinder...
F150redneck they are 315's on my stock 16" rims, basically 35's and they are mickey thompson mtz, and they suck in the winter!

 

I may just replace the MSD with the motorcraft ones from my parts truckif another one goes, but if #4 burns up again I might have to replace the wire harness?

 

Not that a motorcraft cop hasnt prematurely failed.. but they are known for going 100k+
Msd has known to fail within months, few thousand miles...
I bet your old motorcrafts before the MSD were original? and with how many miles...
Just saying.

I would remove them and put dielectric grease if you know they have none. Heat is always a factor when it comes to parts wearing. Though I have never heard of the scenario strictly due to the extra heat.

Your not even sure if it is a cop that is causing it. Could be the cylinder, plug, injector or a number of other things. Swap a known good cop with #4 and see if it stays or goes away

 

I did the swap, from #1 to #4 and the codes changed so when I replaced the msd with a stock one it was fixed, and that's how I knew originally the stock one was burnt when I replaced with msd's.

 

Gotcha. Again, water or moisture would be my only guess as to why the #4 keeps going out.... But if there are no signs of it, then it may be coincidence.

 

After market manufacture like MSD can make decent products. I have a full on MSD ignition in my Mach I and they make good stuff. Thing is though the COP ignition on Modular engines is very high performance right from Ford, There just aint much to make it better. I would think the MSD coils while maybe over priced I would gamble on them working just fine for years. There is some issue with that cylinder..Water excessive vibration. Check the coil bolt make sure the coil isnt loose. Check the cowl gasket and the heater hose that runs above the coil.

 

Thanx Jethat!