Badly fouled plugs in #8 Cylinder

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kevink73

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Have a 2014 ram 1500 160k miles with a 5.7 hemi with codes p0300 and p0308. I pulled all the plugs on passenger side and all looked fine except for the two in cylinder #8. I have never seen plugs get this bad before. Any ideas on the cause? I will post picture of the plugs any help is appreciated.

20200115_130935.jpg
 
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OCDTech

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Jeez, i can't wait to hear the outcome of this, couple of years on here, haven't seen it. Maybe someone else has. Did your truck smoke before this? I had an old camaro one time that had a bad cylinder and smoked like crazy until it fouled the plug like this and started missing.
 
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kevink73

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I don't know the history of the truck. It belongs to someone else that I offered to look at. Took valve cover off and don't see any problems there.

From what he understands the plugs are a few month old. At least some of them are lol. So I have no history of the truck. I would assume a bad ring or valve seals would produce a wet oiled plug. these two where just dried up gunk.
 

OCDTech

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I don't know the history of the truck. It belongs to someone else that I offered to look at. Took valve cover off and don't see any problems there.

From what he understands the plugs are a few month old. At least some of them are lol. So I have no history of the truck. I would assume a bad ring or valve seals would produce a wet oiled plug. these two where just dried up gunk.


I agree. Thing is these engines have their issues, just not these. Weird.

Others will probably give input on this soon.
 
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kevink73

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Thanks for your reply and yeah I've notice. In most case I can always search online for common or particular cause to a symptom on make, year and model of a vehicle. In this case I have found this to be uncommon. Reason I posted. Thinking about pulling Upper intake/Plenum and having a look but decided to post here first.
 
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Burla

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Way too many miles on plugs, I'd start running redline si-1, a 16 ounce bottle every 2k miles for a while, then maybe 1/2 a bottle in that interval. Could be bad injector not spraying right, or incoming gunk from pvc, do you have catch can? Get you a boroscope 100%!! 20 bucks for something. @Hemi395 you have a link to your boro?
 

Fast69Mopar

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My first suggestion would be to perform a compression test.

Next, I would perform a leakdown test on the #8 Cylinder. During the leakdown test listen for air escaping through the PCV and the dipstick tube as well as through the throttle body and the exhaust.

I know you said you removed the rocker cover for inspection but did you feel the rockers on cylinder #8 to see if either one were loose?
 
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kevink73

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Way too many miles on plugs, I'd start running redline si-1, a 16 ounce bottle every 2k miles for a while, then maybe 1/2 a bottle in that interval. Could be bad injector not spraying right, or incoming gunk from pvc, do you have catch can? Get you a boroscope 100%!! 20 bucks for something. @Hemi395 you have a link to your boro?

I'm not sure how many miles are on the plugs. Not my truck. was told some of them was changed 4 months ago and doesn't know witch ones. No catch can on it. I did check PVC valve was oily but valve seemed to move freely. I think my son-in-law has a scope. what would the scope be used for? to look inside cylinder or into plenum?
 
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kevink73

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My first suggestion would be to perform a compression test.

Next, I would perform a leakdown test on the #8 Cylinder. During the leakdown test listen for air escaping through the PCV and the dipstick tube as well as through the throttle body and the exhaust.

I know you said you removed the rocker cover for inspection but did you feel the rockers on cylinder #8 to see if either one were loose?


Will try and find my tester tomorrow it's been 2 years or so since I've used it. I haven't done a leak down test before. So i'll look into how that's done. I assume its to test leaking valves? Rocker seemed fine. I will further insect that tomorrow. it was getting dark by time i took cover off.


I have read that oil can get into plenum from a bad seal and foul out plugs or is that only earlier models?

Thanks
 
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kevink73

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Did you clean throttle body?

No I have not. Can that be a cause? I do plan on taking plenum off to check if its has a bunch of oil in it as well as check #8 intake port for oil.
 

crackerjack1957

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Rebuild/new engine time......ignition spark baking oil to plugs.
Looks a little excessive to be from valve seal...........most likely oil rings.
Could try another cylinder head on that bank if it's cracked.
Compression & leak down test 1st place to start as mentioned by Fast69Mopar.
History of owner on oil/coolant consumption would help with diagnoses.
 

Fast69Mopar

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Will try and find my tester tomorrow it's been 2 years or so since I've used it. I haven't done a leak down test before. So i'll look into how that's done. I assume its to test leaking valves? Rocker seemed fine. I will further insect that tomorrow. it was getting dark by time i took cover off.


I have read that oil can get into plenum from a bad seal and foul out plugs or is that only earlier models?

Thanks
Yes, the leakdown test will give you an idea about cylinder integrity as well as valve/valve seat integrity.

If you hear air escaping from the oil fill cap, PCV or the dipstick tube then we can assume we have a ring/cylinder bore/piston issue.

If you hear air escaping from the tail pipe then we can assume the exhaust valve is leaking.

If you hear air escaping from the throttle body/air intake we can assume the intake valve is leaking.

You can rent a leakdown tester from Oreilly's or Auto Zone to perform the test. The gauge is broken down into percentages of leakage in the cylinder and is color coded green/red for good or bad.

Im betting that a leakdown test will show somewhere above 60% leakage and you will hear air escaping through the oil fill cap or the dispstick tube.
 

Burla

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No I have not. Can that be a cause? I do plan on taking plenum off to check if its has a bunch of oil in it as well as check #8 intake port for oil.

If it is really gunked it is possible it will show you a window into the pcv, oil comes through pdv and is burned in chamber. So since we don't know what it causing this, it is best to rule out everything that is an easy fix. If it is something worse, deal with that when you rule out other stuff. It is very possible a pcv can do this if paired with an injector that is spitting gas instead of spraying it. I'd turn mds off forever at this point, use manual shift and put in top gear, this should disable mds.
 

crackerjack1957

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I would think it would affect all plugs if coming from a bad pcv
 
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kevink73

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Thank you I will go by Harbor fright today and find a compression tester and leak down tester.
Not ever owning a Dodge i'm not familiar with the MDS system.
 

Tim Garceau

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I was wondering what would happen if someone ignored the misfire code and symptoms after losing a lifter for an extended period.
 
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kevink73

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Well picked up a compression and leak down tester. Compression tested a little over 120. Didn't know when you engaged starter that it will continue to crank. So I was able to crank it over and look at movement of rockers. The #8 intake rocker movement was much less than others by about 50%. So i would assume its the camshaft lobe is ate up. Is it worth a cam replacement on it at 160k miles or put in reman engine?
 

chrisbh17

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Well picked up a compression and leak down tester. Compression tested a little over 120. Didn't know when you engaged starter that it will continue to crank. So I was able to crank it over and look at movement of rockers. The #8 intake rocker movement was much less than others by about 50%. So i would assume its the camshaft lobe is ate up. Is it worth a cam replacement on it at 160k miles or put in reman engine?

If you are DIY-ing it, I would think the cam/lifter swap would be easiest and cheapest.
 

Burla

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Thank you I will go by Harbor fright today and find a compression tester and leak down tester.
Not ever owning a Dodge i'm not familiar with the MDS system.

sounds not relevant now, buy mds system shuts down 4 cylinders and send more gas to other cylinders in the name of fuel economy, if you disable it all cylinders fire all the time. Reman engine is a lot more work as you need to remove engine and tranny, cam install is way less work. This is a great dyi cam instal thread, kind of a cam bible around here.
 
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