wristshot

Was not hard. The wiring harness got in the way on the passenger rear, but I was able to get coils and plugs out by moving it side-to-side and/or up. It took me about an hour to do them all. Hardest part was leaning way over, on a step ladder, to get to them.

Hctr154

Thought the same when I swapped mine....I had my son put his size 13s behind the legs of the step ladder to keep it steady.

Ricklee4570

Good to know it is not hard to change them. I am sure the dealer would charge a lot to do this simple change.

Napalm

SO I'll ask again since it's not addressed.

what in the tune - for those of you highly tuned - is causing you to run down your plugs? Is the boost turned up across the power band? Is the fuel lean side of stoich? Or conversely is the fuel rich side of stoich. seeing the blacked plugs I am guessing it's running slightly rich.

Does the engine run any hotter in general? Again I'm guessing so? Is the spark timing rather high?

I understand if you don't know because it's a can tune from ______ but it seems to be something significantly changed from where the stock system runs.

MNSportsman

iTrader: (1)

Tuners change a variety of parameters in the PCM, most of which is proprietary to their tunes. I'm sure it's a combination of these changes that drives their recommendation on frequency of plug changes (at least in Livernois's case, not sure what frequency other tuners recommend).

If it's keeping you up at night, why don't you call one of the tuners and find out for yourself on the specifics you're looking for.

Napalm

it's not so much as keeping me up at night just an issue I have with the usual internet isms of so and so says you have to do _________.

when others don't and you don't see any real evidence of that logic train.

Looking at the OP's first spark plugs and him confirming via feeler gage that they were still within the .030 spec - then clearly they were fine for some more time.

so perhaps it needs to be changed closer to 50K, 60K or something. and that'd be fine but I would like to know why it happens that way.

wristshot

Cylinder pressure typically goes up when you make more power (i.e. from increased manifold pressure, spark timing, injector timing, optimized air/fuel ratio, raising or removing torque limits, etc.). For a given spark plug gap, it takes a higher voltage (i.e. more power) to "jump the gap" with increased cylinder pressure. If there is insufficient power to "jump the gap", that cylinder does not fire (i.e. a misfire occurs).

Ford engineers determined a plug gap of 0.028" - 0.031" was sufficient for the stock power levels. You don't want to go any less than necessary, because a larger spark kernel (from a larger gap) aids in starting the flame front. There are trade-offs in everything.

There seems to be a general consensus, from the high performance community, that a 0.028" gap is closer to ideal for the additional power levels on the ecoboost trucks with general bolt on performance adders (i.e. tunes, exhaust, intake modifications) and stock coils.

I wanted to verify my plug gap was near 0.028" (still within factory tolerance mind you) and since I was removing the plugs I was going to go ahead and replace them. I was surprised to find ALL of my plugs were way over factory tolerance at 0.035" plus (I verified my plug wire gauge with 2 different sets of dial calipers). Now from inspecting the 33,000 mile old plugs they did not look worn. The electrodes were sharp and ground straps looked OK, based on this I don't think the gap widened significantly from the day is was new. I might have been able to re-gap them and reinstall, though the electrode face and ground strap may not have been parallel.

My truck had been tuned for some time. I had never experience any misfire that I was aware of, or had any misfire DTC codes with the 0.035" gap.

As far as the tunes go, the only thing that I am aware of that can be calibrated ignition wise that would affect spark plug longevity is the coil dwell. There are Normal and High Output Coil Dwell (saturation time) tables that vary based on coolant temperature and battery voltage. Increasing the coil dwell time will have a longevity affect on both coils and spark plugs. How much; I don't know.

swampvol

Old thread revival!

I replaced the plugs on my 5* tuned 2.7l and the old plugs looked decent and all had a snug .028 gap.

No signs of misfires that I could tell, so probably could have gone another 10k at least.

acdii

How's the pit look? If anything like the 3.5 plugs, the pit increases the gap even though the gap shows correct, which is the cause of misfires @30K miles in the 3.5.

joemomma

I changed my all-stock '16 3.5 plugs/boots at just shy of 40k miles. They all had a pronounced "pit" as shown above. The boots were fine.