thanks to everyone for the years of me solving my own issues by the use of this forum.

2004 f150 4.6L
a few month ago i blew my first sparkplug (#6). got it fixed and everything was fine. fast forward to last week and blew another one (#5). i was in the mountains and didn't have any other option but to continue driving the truck for an hour till i was out of the mountains and could get it back to civilization. i got the #5 fixed up with a new sleeve, plug, coil, but nothing i do has stopped the miss in #5. replaced boot/coil, plugs, check spark (which is good) nothing.
computer still throwing the code P0305, not that you need the computer to tell its the one missing, simply pulling the lead off the coil changes nothing.

any ideas on what this could be? or how to track it down? did driving the truck with a blown plug for an hour damage something else - my guess is yes.
i have not checked the compression in the cylinder yet and was going to do that next. but can't think of anything else.

appreciate any thoughts you may have.

josh.

 

Yeah, do that. You need to determine if there's now a "base engine" concern or not.

What are you using for repairs of the blowout?

 

The Cadillac repair is the timesert. Others will fail, I hope you are not using helicoils . . Yes do the compression test . Since you are blowing threads -are you torqueing these plugs 25 - 28 foot pounds ,these are not the heads with too few threads . Is carbon track coming up thru threads on number 5 blacking porcelain ? did you drill this out to put insert in ? If you did maybe alum down in cyl . or on valve seats .

 

thanks for the reply.
i believe the shop that fixed the first blowout used the Cal-Van sleeves, and its also what i used for the 2nd blowout.

i can't say for a 100% certainty i got every shaving out of the cylinder when i drilled out the plug, but i used a scope and blew it out till i couldn't see anything in the cylinder with the scope. also making sure both valves were shut at the time.
i would like to think that isn't the issue of shavings in the cylinder or valves but i guess i can't rule it out if nothing else seems to be the issue.

i did check the spark on #5 and was firing normally.
i can't find my compression tester so waiting on another one - will test when received.



not seeing any carbon track and have been plugs are being torqued at 25lbs.

appreciate the feedback.
j.

 

One trick I learned from southmain auto eric , leave the hole open and start engine and hope any contaminants get blown out thru hole. Sounds like you know what you are doing ,good luck .
The ones I helped with were thread sealed with a high temp red thread locker. But the guys were all wanting to try to use it before it had time to dry . They couldn't afford timesert either. We used a lot of grease on the drill bit to pu filings .

 

The CalVan/SnapOn insert system is an excellent one, ranks on par with both the TimeSert and Lock-N-Stitch inserts. If properly installed, it's as close to bulletproof as one can expect.

 

I heard of that calvan system , I'm sure its good . I just don't know if it uses hi temp sealant and peen on the top .

 

well.. finally got to testing the compression on #5 and its less than 50.
sounds like i got a stuck valve or something. when i pulled the plug its black and soaked smells like fuel.

 

Can you tell if the air is coming out around the insert . Or the exhaust valve /intake / crankcase ... I suppose you need to know what to fix -pull head or is it rings. .
It is an interesting problem . A scored cly wall would be a deal breaker . .The head fix would be the interesting part . or would you just go with a new/reman head.

 

I meant the test where you pressurize cly with air and listen to the intake ,exhaust, crankcase ..

 

I would suspect that, despite your stated precautions, you may have nicked a valve or dinged the top of the piston when installing the second insert.

A borescope inspection *might* reveal the issue (particularly if piston or cylinder wall damage) but it's likely the head is going to have to come off for verification of valve damage.

 

thanks for the follow ups.
i did stick a scope in and didn't see any damage to the piston. it was all the way in the down position so unlikely the cause. however nicking the valve could be possible. i put a scope down while turning the crankshaft and could see the valves open and shut. turned it where i couldn't see either valve and the piston was at the bottom, however that doesn't mean i didn't nick it as visibility was pretty low. i think this is probably the cause as you mentioned @projectSHO89 .

i ended up taking it to two different, well respected, mechanics in my area and both of them said the exact same thing. not worth fixing and i should just put in a new motor. they were both in the same ballpark on figures @ 7k all in. i was surprised that neither one would take the head off to inspect. they both said they wouldn't touch it to repair the issue. they were both very familiar with the issues of these motors and said it just wasn't worth it with so many miles on the motor. new motor or buy a different truck is what both said to me.

i guess 7k is better than a different vehicle. the new motor comes with a 100k mile warranty.

thoughts?

 

Thats my plan if something serious happens to my motor . A reman at those miles with a warranty is better deal as long as the truck is in real good shape . But i plan on doing some of the work myself cleaning /removal etc . Perhaps I can get a mechanic friend to help for 1k with the motor at $3200 and fluids seals etc for another 500 .
No one is going to clean and take the care that a diy owner will do . I want to make sure I get a good oil pump and steel ratcheting tensioners .

 

just bought a 2006 f-150 with 210,000 km. run real rough and no power under load. did scan and can't remember what code it was shooting, but it said mis fire #5 cylinder. so started checkin this out . turns out previous owner probably did the same cuz #5 coil over plug was new. to top it off when i tried to pull #5 plug as well as a few others to have a look at them the heads where socket goes over was rounded off, so someone previously tried to get plug out but failed.took me some time but i got those plugs out without braking any .replaced all plugs. make along story short ,i u tubed the problem and on ford maluka or something like that describes very well that the code will show misfire on #5 but the reason is because plugged catalatic converter and the exhaust can't leave so the pressure backs up to#5, causing misfire.3 mechanics i spoke with disagreed to this .i changed catalatic converter and bingo! problem solved. before i changed catalatic convert i tried just changing o2 sensors but it did'nt help. truck now has awsome power shifts like a dream, BUT still burns rich which is why the cat probably got plugged up in the first place. so after researching i will see if i can find air/vacum leak in the intake manifold then check out the injectors. runs very well now even burning rich just don't want to repeat problem. to back up a bit i changed cat before changing plugs. and rn very well before changing plugs. i'll post some of the tools a fabricated to get those plugs out later cheers!