D6H Sputtering

[Oldcatpusher]

D6H 3zf00772 sputtering throughout all rpms engine hot or cold. Checked fuel lines, filters, and injectors. It's not a dead miss. Just a sputter. Small power loss. You can crack the injector lines and there's no 1 injector that allows down the engine any more than the others. No smoke. Just the normal light black smoke when you let off the deaccelerater. Checked the valve lashing. Everything is in spec. Had a lot of carbon build up on my injectors. Any other ideals on things to check? Dozer starts fine. Kinda has a little sputter when you start the engine sometimes instead of popping right off but it still starts without having to hold the key any longer than normal.

 

[Nige]

Basic questions: -
Engine hours?
Injector hours same as engine or less? If less, how long ago were they replaced and are they OEM or aftermarket?
Problem started suddenly or built up over time?
Any recent repairs or service work?
Does the engine consume oil at all?
Air filter replaced recently?
Have you checked fuel pressure?

 

[Oldcatpusher]

Unknown engine hours. Approximately around 8000. Doesn't hardly use oil usually only when it gets close to an oil change. Injectors were changed out yesterday. The ones before that were cat reman replaced 2 and a half years ago and went back with cat reman. I don't think the injectors were an issue. Only 4 didn't test good. New injectors made no noticeable difference. Maybe a little less smoke on acceleration but it's hard to tell exactly with a light spudder . Turbo rebuilt injector pump and injectors 2 and a half years ago. Other than that oil changes around every 150 - 200 hours. Transmission oil changed and transmission screens cleaned. Oil and transmission cooler cleaned . Approximately 250 hours ago. Fuel pressure hasn't been check.

 

[Nige]

Just for completeness........
Recent air filter servicing?
Problem started sudenly or built up slowly over time?
What happens exhaust smoke-wise if you go straight from Low Idle to WOT.?
Is it burning more fuel than normal.?

TBH my first suggestion would be to check fuel pressure.

 

[Oldcatpusher]

Yes good air filters. It started all at once. I went into a pile and when I went wot it started all of a sudden. Normal small puff of black smoke comes out from idle to wot . smoke hasn't changed at all since problem started

 

[Oldcatpusher]

Also hand primer pump changed after dozer started sputtering .

 

[Oldcatpusher]

My mechanic thinks it could be maybe a crack in the head gasket between bores or maybe a piece of carbon stuck under a valve not allowing it to close all the way. He doesn't believe it's fuel related.

 

[Nige]

Without having checked fuel pressure I would disagree with your mechanic. It might not be fuel-related but right now nobody can say for sure if it is or not because all the possible tests to eliminate the fuel system as the root cause haven't been done.

You said the valve set had been done but it changed nothing. Related to the idea of something stuck under a valve surely that would show up in a valve adjuster screw way different in height to the rest..? So if your mechanic did the valve set surely he'd have spotted something like that.

Do you do oil analysis..? If not how about taking a sample and having it analyzed for water, glycol, or fuel in the oil..? That would give you a good idea if something was getting where it shouldn't.

 

[Oldcatpusher]

That's why I was asking on here cause I thought it might be fuel related. I turned the motor over for him while he set the valves. They weren't bad at all. I had set them myself about 2500 hours ago when I replaced turbo and injector pump. I've been pushing this morning with it and it runs the same temp but has a slight power loss. I have great flow from the tank through the hand primer pump. Haven't checked fuel lines beyond that.

 

[Nige]

In that case get the gauges on the fuel system and check the pressure, plus have an oil sample analyzed as recommended above would be my thoughts.

 

[Oldcatpusher]

How much pressure should I have going into my injector pump?

 

[Nige]

Measure the pressure at the 1/8" pipe plug on the secondary fuel filter head. At High Idle RPM the pressure should be a minimum of 15psi.

 

[Oldcatpusher]

Ok I'll check that. Thanks

 

[Bls repair]

Exhaust restrictions?

 

[Oldcatpusher]

Any ideal to what a part number would be for a guage that you can screw into that port and leave it there permanently. I've seen them before on filter bases but can't find a part number for them.

 

[Nige]

I think if you did that the vibration would kill it in short order. There's a reason why pressure gauges are generally mounted in the dash panel, or at least somewhere where the vibration is not quite so pronounced.

 

[Birken Vogt]

I have seen a number of oil pressure gauges direct mounted to an engine fitting. Seemed to work all right over the lifetime of the engine.

 

[Oldcatpusher]

Going to check fuel pressure tomorrow. Had to go purchase a gauge that would show low psi. Mine started at 50. Also there is a noticeable noise. Almost sounds like an exhaust manifold leak with the miss but there is no exhaust leak. The more load on the engine the more noticeable. I know when diesels misfire they make different sounds but I didn't know if that would help narrow the problem. Been over 2 years since I've had any engine trouble on my machines. Maybe I'm over thinking it

 

[Shimmy1]

Have you happened to remove the oil filler cap while it's running? First thing I do when I hear something amiss.

Also there is a noticeable noise. Almost sounds like an exhaust manifold leak with the miss but there is no exhaust leak. The more load on the engine the more noticeable.

I sense more in-depth surgery in your future.

 

[RZucker]

Going to check fuel pressure tomorrow. Had to go purchase a gauge that would show low psi. Mine started at 50. Also there is a noticeable noise. Almost sounds like an exhaust manifold leak with the miss but there is no exhaust leak. The more load on the engine the more noticeable. I know when diesels misfire they make different sounds but I didn't know if that would help narrow the problem. Been over 2 years since I've had any engine trouble on my machines. Maybe I'm over thinking it

I'm late into this, but have you found the pre strainer/screen between the tank and transfer pump and cleaned it? Been there with a 5H before.