Oil on lower spark plug only, not valve cover

[pcs]

staying up to date with oil changes i see. looks clean in there.

 

[MTF]

2011, 115k. Have had a slightly rough idle issue for a while. Among other things, changed all 16 plugs and 2000 miles later decided to pull them again to check gapping. When I originally pulled them, cyl 5 and 6 bottom plugs had oil on them on the end going into the combustion chamber. Anyway, all gaps were correct but I noticed the same two plugs had oil on them again. I confirmed this is NOT a valve cover leak, the outside of the plug hole is dry. Any ideas on what may be causing this and if it effects much? I understand the top plugs do most of the work and the bottoms basically just help with emissions? Anyway, not sure how to resolve this issue if someone knows what can be done, I hope it doesn’t require pulling heads.

What gap are you going with? Ford is using a pretty big gap OEM recommendation.
Try using a tighter gap.
And are you keeping up with injector cleaning? If the spray pattern is weak, it could be the reason?
And running the highest octane available where you live?

 

[2011reptar]

What gap are you going with? Ford is using a pretty big gap OEM recommendation.
Try using a tighter gap.
And are you keeping up with injector cleaning? If the spray pattern is weak, it could the reason?
And running the highest octane available where you live?

I went with factory gapping. I replaced all 8 injectors as well just to be safe. All looked good, and the new ones obviously looked good as well before throwing them on. I am running 91 which is the highest here, though I have put octane booster in once to make 93 and it didn’t help with that, though I could hear a little less pinging when in low Rpm range on a gradient.

Something weird today is I left the truck running while fueling up - dumb but it was 3am and I was tired. But the truck started almost dying during the fuel up. Every few seconds the idle would dip and almost stall, then come back. Once I was done fueling it stopped… so maybe the other general idle issue is all fuel pressure related? I have fuse 27 relocated and the fuse itself looks fine.

 

[MTF]

I went with factory gapping. I replaced all 8 injectors as well just to be safe. All looked good, and the new ones obviously looked good as well before throwing them on. I am running 91 which is the highest here, though I have put octane booster in once to make 93 and it didn’t help with that, though I could hear a little less pinging when in low Rpm range on a gradient.

Something weird today is I left the truck running while fueling up - dumb but it was 3am and I was tired. But the truck started almost dying during the fuel up. Every few seconds the idle would dip and almost stall, then come back. Once I was done fueling it stopped… so maybe the other general idle issue is all fuel pressure related? I have fuse 27 relocated and the fuse itself looks fine.

Canister Perge valve is something you should look at.
And while the valve might be good, the O-rings do dry out and leak.
Ford found that on mine while doing a smoke test.
Do you always go to the same gas station?
You shouldn't have any pinging, unless you're running a Tune. Are you running a Tune?
NA guys here on the forum do run a colder spark plug and gap to .38 and tighter, to help with pinging.
Us supercharged guys gap all the way down to .28 to keep the forced air induction from blowing out the spark.

I like using both STAR BRITE Star Tron Enzyme Fuel Treatment (for water in the tank from ethanol) and a good injector cleaner.

 

[2011reptar]

Canister Perge valve is something you should look at.
And while the valve might be good, the O-rings do dry out and leak.
Ford found that on mine while doing a smoke test.
Do you always go to the same gas station?
You shouldn't have any pinging, unless you're running a Tune. Are you running a Tune?
NA guys here on the forum do run a colder spark plug and gap to .38 and tighter, to help with pinging.
Us supercharged guys gap all the way down to .28 to keep the forced air induction from blowing out the spark.

I like using both STAR BRITE Star Tron Enzyme Fuel Treatment (for water in the tank from ethanol) and a good injector cleaner.

I did replace the purge valve as well unfortunately. I am the dealer part desks number 1 customer the last few months.

No, I usually use Costco, but 7/11 was the only place open at 3am. It did stop as soon as I stopped pumping gas. Just a weird deal. No tune, and the pinging I hear on occasion is VERY light, it’s similar to what I’ve heard on other vehicles running slightly lower octane. Pinging goes away completely with the octane booster - the real stuff that’s like $20 a can. Idle issue remains however.

Good to know about the plugs. I went back with OEM, but may pull and re gap, just to say I’ve tried it. Short of a computer issue or a fuel pump issue, I’m not sure what the idle issue could be, but maybe that will help, may help with the oil on the lower plugs as well.

I am still getting great mileage and power, no other issues period other than the idle fluctuation. I am trying to just live with it, but if you couldn’t tell, I’m a little bit obsessive over my vehicle and try to be proactive. I’m about $3000 into replacing stuff under the hood, which sucks, but also, she’s all but had a mild rebuild at this point! I did the water pump, thermostat, tensioner pulleys and other stuff today as well. Next will be the AC compressor and power steering pump. I figure it’s better to buy this stuff now than wait til the ford back stock starts drying up. I have a C5 vette that even though it has an LS1 that was in tens of millions of vehicles, factory parts are starting to get used to find. Had to pay $750 for a new old stock alternator.

 

[pat247]

It has been mentioned in this thread already and I will emphasize it further, fuel system cleaner. A product that I can't recomend enough is BG 44k, it's not cheap at $30 per can/bottle and you need 2 for the 36 gallon tank. I've used BG 44k every 10k miles since my Raptor was new, now at 185k. When I changed the spark plugs the first time at 160k I was shocked at how well the truck ran considering the condition of the plugs, the gaps were all over the place. The idle on my truck fluctuates some but not enough to be a concern. A vacuum leak will cause an erratic idle condition also if you haven't checked for that already. Good luck finding the cause.

 

[2011reptar]

It has been mentioned in this thread already and I will emphasize it further, fuel system cleaner. A product that I can't recomend enough is BG 44k, it's not cheap at $30 per can/bottle and you need 2 for the 36 gallon tank. I've used BG 44k every 10k miles since my Raptor was new, now at 185k. When I changed the spark plugs the first time at 160k I was shocked at how well the truck ran considering the condition of the plugs, the gaps were all over the place. The idle on my truck fluctuates some but not enough to be a concern. A vacuum leak will cause an erratic idle condition also if you haven't checked for that already. Good luck finding the cause.

View attachment 484819View attachment 484820View attachment 484821

I have a big gallon sized jug of Lucas I measure out and use every fill up. I’ll look into the 44k though. I cleaned the fuel rail when doing the injectors a few weeks ago as well.

I’ve read on other threads that the computer leans the truck out to almost the point of stalling while idling for EPA regs and that this as well as the slightly bigger cams compared to the standard 6.2 can cause a bit of an idle shudder feeling. So who knows, maybe chasing ghosts over here. The only thing I know definitely is the oil on the bottom plug issue. That might be related I guess, but since the second plug mostly just decreases pollutants, idk how much it’d effect idle for example.

I used to only drive land cruisers where you can balance a quarter on the engine, so part of it is probably me having to get used to a bigger engine with more performance than comfort engineering.

 

[Chewie]

Just spit ballin here, since you’ve done all kinds of leg work. Are the 5 and 6 bottom plugs actually firing?

 

[mprice1234]

I agree with @pat247 on the BG 44k, it is a solid product that works! Expensive yes, but you pay for what you get.

 

[2011reptar]

Just spit ballin here, since you’ve done all kinds of leg work. Are the 5 and 6 bottom plugs actually firing?

You’ve got a point, that’s a good question. That might explain things. I did put on new wires and I’ve checked Forscan and it’s not showing any issues, but it doesn’t specify which plugs are working, only the cylinder. Hmm.

I did find this thread which seems super close to my issues, but of course there was no follow up and OP doesn’t look to be active anymore.

GEN 1 - 6.2 Misfire, no DTC(s), Plug oil fouled?

Last year around this time I replaced all 16 plugs\wires, recently replaced boots and pellets on the coils. Truck currently has about 98k, less than 10k on the plug in the pics. During my state inspection last month the tech noted he felt a misfire at idle. I figured he wasn't used to the...

www.fordraptorforum.com