Dtc 93

[1Ton]

I was stopped at a light and it started making this loud Thunking noise. Sounds like it is coming from the air intake. Got it towed home and pulled a single code. DTC 93 #6 cylinder balance fault. Lift pump is functioning. (don't know at what pressure) 1 year old lift pump.(bought new)

I used some software to turn the injectors off one at a time to see if the noise would go away. It didn't.

Slight white smoke from tailpipe.

No oil in the coolant and no coolant in the oil. No fuel leaks that I can see.

Any thoughts? What am I missing?

Thanks

Darren

[john8662]

At least you know which hole.

Pull the valve cover on that side and inspect Cylinder #6 parts. Most likely a rocker arm retainer broke, plastic/nylon button.

If that not it, look at the valve spring, pushrod, lifter.

J

[1Ton]

Pulled the valve cover. Pulled Rockers assembles. #4 and #8 Exhaust Push Rods bent. #8 was actually broken. #6 looked fine. Springs look good in all.

Lifters???

[1Ton]

Pulled the cylinder head last night. Glow plugs were intact. No signs of cracks. The head gasket did not appear to be blown. Nothing in the cylinders.

Is it possible to have two lifters fail at the same time? There has got to be more to this issue.

I will do a good cleaning on everything and check for cracks again.

Stuck valves? I will check for that as well. :confused:

[john8662]

Usually when it's bending push rods, there is a reason for it.

Wipe down the pistons on the offending cylinders with carb cleaner and see if there are any signs of piston to valve contact.

The only time I've bent a push rod on one of these is when I had piston to valve contact from floating the exhaust valves (too much boost/rpm).

Since it's easy right now, pull the two lifters and have a look at the roller, also that the guide plate that holds the lifter in the correct position for the roller is in tact.

[1Ton]

Finally found the time and got her back together. Failed Lifter in #8. I decided that since I didn't know how many miles were on these lifters, I would just replace them all. 16 new lifters and actually 5 new push rods. 2 had to be replaced but I found 3 that had a very slight bend. I could only see it when I rolled them on a piece of glass. Better to be safe then sorry. She runs better than ever.