Gen 1 6.2L engine misfire problem

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StuMac9

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My engine is misfiring 2011 6.2L 73K Procharger D1SC = Forscan says cylinders 5 and 8.
Took it to a repair shop and it is not the plugs (they were changed 8k ago) - repair shop says not coils as when swapped the misfire does not move etc.
So they say I need a new motor ! Since cylinder 5 is the easiest to get too the shop says there is no pressure coming from that cylinder hence need a new motor. I heard these engines were pretty bullet proof but there are some issues.
It idles rough and I babied it to the repair shop - around 20 miles, it wont go over 4000 revs and is smoothest around 2500 revs.
Does this sound more like valve springs ? Is it regular that more than one valve spring at a time can break e.g 5 and 8
The repair guy says new engine and is reluctant to look into valve springs I think because of the work involved in removing some of the Procharger parts as well. What do you think - please help
 

FordTechOne

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The 6.2 is a reliable engine, but it was not designed for forced induction. That throws all of your reliability out the window.

It’s possible that the loss of compression on cylinders 5 and 8 is due to broken valve springs. Many times the valves will drop into the cylinder and destroy the engine, but you may have gotten lucky. If they’re broken they will eventually fall into the cylinder, so I wouldn’t recommend even starting it until you can get the valve covers off and inspect the springs.

If the valve springs aren’t broken, you’re most likely looking at cracked piston ring lands and/or damaged piston/cylinder walls. At that point you’ll most likely need a replacement short block at minimum.
 
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My engine is misfiring 2011 6.2L 73K Procharger D1SC = Forscan says cylinders 5 and 8.
Took it to a repair shop and it is not the plugs (they were changed 8k ago) - repair shop says not coils as when swapped the misfire does not move etc.
So they say I need a new motor ! Since cylinder 5 is the easiest to get too the shop says there is no pressure coming from that cylinder hence need a new motor. I heard these engines were pretty bullet proof but there are some issues.
It idles rough and I babied it to the repair shop - around 20 miles, it wont go over 4000 revs and is smoothest around 2500 revs.
Does this sound more like valve springs ? Is it regular that more than one valve spring at a time can break e.g 5 and 8
The repair guy says new engine and is reluctant to look into valve springs I think because of the work involved in removing some of the Procharger parts as well. What do you think - please help
I have 2011 6.2 with 108,000 mi with misfires in cylinder 5 and 6. The Ford dealer did a complete teardown of the engine after all plugs, coils changed and tune up and still rough idle and misfires. They found no obvious signs of damage or anything broken, but more than usual wear on cylinder 6 intake cam lobe and and roller, and also found rocker arm roller scored. I believe this hapened due to running on low oil, and lack of basic maintenance such as to air filter. Instead of replacing engine, which is easier said than done, I'm trying to repair what was neglected and no doubt led to the current situation.
 

CoronaRaptor

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My engine is misfiring 2011 6.2L 73K Procharger D1SC = Forscan says cylinders 5 and 8.
Took it to a repair shop and it is not the plugs (they were changed 8k ago) - repair shop says not coils as when swapped the misfire does not move etc.
So they say I need a new motor ! Since cylinder 5 is the easiest to get too the shop says there is no pressure coming from that cylinder hence need a new motor. I heard these engines were pretty bullet proof but there are some issues.
It idles rough and I babied it to the repair shop - around 20 miles, it wont go over 4000 revs and is smoothest around 2500 revs.
Does this sound more like valve springs ? Is it regular that more than one valve spring at a time can break e.g 5 and 8
The repair guy says new engine and is reluctant to look into valve springs I think because of the work involved in removing some of the Procharger parts as well. What do you think - please help
If you have any basic mechanical skills, you can get the valve cover off on that side. You don't need to worry about putting it back together, get a box and put the parts in it orderly, bolts in bags, etc. Like @FordTechOne mentioned, once you have the valve cover off, look at the springs, you won't miss if its broken, will look different than the others. If you don't have any broken valve springs, it is going to be very expensive if you can even find a motor. If you find a broken valve spring or two, then find a shop to do the work, will still be expensive if the valve stem is broken. Keep us updated.
 
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