#6 not firing - Diesel Forum

fordnatic68 · 11-10-2012, 06:53 PM

Hey gang long time no post. Got an issue with #6 not firing. It started while driving a 400km trip I noticed it right away. Tried resettig pcm by batt disconnect, i disconnected injector while running no change. I reinstalled a new injector no change. Did a leakdown test air out the intake side of turbo tells me stuck/bent valve. Pulled valve cover one rocker was extremely tight no play at all like the rest of them.

Im just looking for some insight before I pull the heads and dig deeper. I did overheat last summer while pulling some mountain roads when fan clutch failed. It hit 260+ degrees. No coolant in oil and no oil in coolant. Im suspecting a ring or something. any advice im all ears guys thanks;]

dannyboy950 · 11-10-2012, 10:47 PM

Sounds like you have a lifter pumped all the way out and stuck keeping an intake valve from seating closed. Probably #6 Since it is a valve problem switching the injectors would make no difference.

dcovaleski · 11-10-2012, 11:23 PM

A couple things don't make sense though. First, what rocker was tight? And what position was the motor in? If it was on the intake or exhaust stroke on that particular piston, then one or the other rocker would definitely be tight. Second, why would you suspect a ring? Rings hold compression in a cylinder, or oil from getting into a cylinder from the wall. Bad rings, oil or compression, would not shoot air out of an intake valve.

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fordnatic68 · 11-11-2012, 12:13 AM

I suspected a ring due to overheating and possibly making the rings brittle. All the rockers seemed fine but one, it was unmoveable. All the others had some sie to side play. I have to do some more diagnostics. Ive gone through a nasty divorce this year n my heads really not fully in the diagnostics game. Im thinking leakdown test again and go from there.