truckbed

So I'm getting the famous misfire due to plugs/COPs... again!

Quick timeline (dates approximate):
~2010 replaced all plugs and COPs, broke 1, all went well with Lisle tool, no misfire!
~2013-2014 got misfire again, replaced all plugs (figured at $13 each and the time to pull them, might as well replace), no misfire!

Truck has 174k miles right now. Since the last change I have put maybe 8k miles on the truck as I don't drive it much anymore. Now I'm getting the misfire again!

I pulled the 4 easy ones on the driver side and checked them out and put pics below. Do they look extra gunky to you? Do you think there is some extra crap inside the engine that is getting all over the electrodes? I could pull the passenger side but man I'm trying to avoid paying another $100 for this. These plugs should last longer than a few years and 8k miles, right?

The ones in the motor now are Motorcraft 515 and still misfiring


driver side front

driver side front

driver side front

driver side 2nd from front

driver side 2nd from front

driver side 2nd from front

driver side 3rd from front

driver side 3rd from front

driver side furthest rear boot and plug were the gunkiest

driver side furthest rear boot and plug were the gunkiest

driver side furthest rear boot and plug were the gunkiest

driver side furthest rear boot and plug were the gunkiest


I don't mind replacing them all again and also the COPs if needed, but I just don't want to have to do it every 3-4 years. Also, starting to think maybe the engine needs to be flushed out or something with all that thick gunky stuff on the plugs. I rarely drive it but have run full synthetic since I bought it with 30k miles in 2007. Truck just rolled over to 174k last week.

I appreciate any help or ideas!!

Heavy_Metal

Im wondering why the rust on the end of the boot? Are you using water to clean the engine?

gone postal

Boots are shot. COPS are likely fine, as are the plugs. Change boots, clear codes and run it.

Misfires have more than one cause, no sense in spending $13/plug when they're probably fine.

truckbed

Thanks for the replies guys. The pictured boot was the worst of them all, closest to firewall. The others were fine, but I didnt pull the passenger side.

How would the rubber boot be "shot?" Its not eaten up or deteriorating so how could that cause a misfire?

That rusty brown color would not wash off so i put extra dielectric grease to keep it from arcing or whatever through the brown stuff.


edit: btw its good to hear that the plugs look ok, leads me to believe the black stuff on the plugs is normal..?

gone postal

The discolorization looks like they are, in fact, deteriorating. Used to seeing dielectric grease as white or clear, not sure why that grease looks brown.

Summers22

iTrader: (2)

You should always replace the COP boots and springs along with spark plugs.

F150Torqued

There's where you are mistaken and missing a key point that could be the source of all your misfire troubles.


These engines run very lean and near the ragged edge of every thing that makes for successful ignition (cam retard for lots of EGR, and that lowers compression - trying to achieve max economy and emissions). To compensate for those factors, spark ignition runs VERY high voltage - 30 - 40k volts. Hair line heat cracks result from all the heating/cooling cycles of the boots. Those hair line cracks then adsorb moisture from condensation that also is aggravated by the heating / cooling cycles and provides spark-over paths. Yes, every plug change should be accompanied by NEW boots & Springs and cleaning/burnishing all electrical contacts. Keep all carbon and greasy finger prints off plug porcelain.

redfishtd

Use dielectric grease sparingly . It is an insulator not a conductive gel ,keep it off metal electric parts . . It' s purpose is to stop boot from heat seizing to plug and to keep moisture out of boot . Boots and springs not very expensive ,napa has them, belden good brand . Boots deteriorate with heat -age- oil etc .
They may look okay but would you hold them in your hand while I put 30,000 volts thru the center ,no I don't think so either . Those plugs are 5 inches down there, any jump to the head is a misfire . Hunting misfires can get expensive and labor intensive . . That brown stuff maybe rust , rust conducts it may be contaminating plug insulator . .Anyway if its dirt its contaminating dielectric .
Clean cop contacts real well . Torque plugs in 25 to 28 foot pounds . Clean out cly snout area of plug with carb cleaner .
Those plugs look like you might have used anti sieze on them . That was a temp ford tsb solution until new plugs redesigned, not necessary any more they don't twist off now . Anti seize can cause a lot of trouble if not used sparingly, I see anti -s stuff down around the tip ,thats a no - no . . I only use nickel it is rated high temp use a tiny dab on threads and cop bolts . . Keep it off every other thing ,keep your hands clean .
Maybe this vehicle sitting in high humidity area . sometimes sitting on grass moisture will come up at night and collect under hood . Need to run it every week to temperature .
I worked on extreme high voltage for 40 years ,its touchy . 765kv .

redfishtd

There have been numerous reports of bad sp515's out of the box . I don't use them .I use 7989 champions and they are expensive .

Navyslideby

You can add me to that list, I bought 8 new sp515 plugs and had a misfire that over the course of 5 miles became a no fire at all. Changed cop, no change. Took the best looking of my old plugs, cleaned it and put it in. Runs like a dream