Diesel gurus, need advice

[Skillet]

Hi fellas,

Up here fishing in AK and have an issue that I need to sort out ASAP, going the board can get me educated here a bit before I start talking to the shop here in Sitka.

My main engine is a Sisu inline 6 turbo diesel, 6.6 liter, Bosch P7100 injection pump with pencil injectors.  It just started missing and  making a lot of oil.  Diesel in the crankcase, to the tune of gaining about a gallon an hour at reduced running speed.

 I was in Lituya Bay when it started (after taking a load of fuel at Elfin Cove),  and have been running the boat back to Sitka since 10 am yesterday. I'm a hour out of town now.  Every three hours, I'll shut down and take out 5 gallons, put two gallons of fresh oil back in to get it back to the low notch on the dip stick.

At idle, I'm dropping two cylinders (#3 and #6, checked by cracking the feed lines at the injectors), and running it feels like I'm only down one. 

I question the fuel I got, and switched over to a known clean tank of fuel.  Bad injectors?  I'm a little smoky, but not really heavy. Just a blue haze.  P Pump seal gone, dumping fuel into the crankcase?  Worse?

Thanks in advance-

Chris


@woodchuck
@jackelope
@buckmark
@mudman
@southpole
@anybody else who has insight

[Dysfunctional Vet]

Possibly failed injector sleeves.

[BrandonWatts]

Sounds like tips on the injectors are toast. Those p7100 are pretty hard to kill. Wouldn’t run it much longer until you get them replaced. You are essentially washing the cylinder with diesel and not getting any oil on 3 and 6. Run it too long and you will be doing pistons and liners too.

[Skillet]

Thanks guys.  Necessity dictated I get back to Sitka to get these fish off and get to a place that had some level of service, so that meant a 20 hour run on a sick engine.  No AAA out here, you bootstrap yourself out of anything you get yourself into.

Sounds like the first place to start is the injectors. I'll get a set flying my way asap and let you all know how it works. Really hoping the pump is still kosher, and didn't torch any cylinder sleeves, pistons or bearings.

Might take a quick nap first. 

[Mudman]

   I hope having to run it back didn't damage other parts.  I do wonder why 2 at same time?  Maybe 1 was going and ya didn't notice?  Its a wear part and Im sure you run great filtration so good luck, I think it will be ok with new inj. 

[dyhardhuntr]

If I was too guess I’d say an issue with those 2 injectors. Could be they are dribbling or it lost a tip(hope not). I would pull an injector and see if you can see a crack or missing tip. If not, and it’s available, have them tested. Usually if it’s an injector sleeve it’s fuel in the cooling system. Although I’m not familiar with the engine manufacturer. I’ve worked on countless Cummins,cat, Detroit and such engines. Also think outside the norm. If there is anywhere that oil and fuel are in the same vicinity, give it a look see. Good luck!


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[Knocker of rocks]

If there is anywhere that oil and fuel are in the same vicinity, give it a look see.

There were a number a farm tractors where pressurized diesel could enter the crankcase at the injector pump engine connection

[Woodchuck]

You didn't just have this thing "tuned" did you?

[Boss .300 winmag]

🤔

[Skillet]

You didn't just have this thing "tuned" did you?

Stock as a rock, man. I don't think Sinister has a fuel map for my application.
 

[Skillet]

If there is anywhere that oil and fuel are in the same vicinity, give it a look see.

There were a number a farm tractors where pressurized diesel could enter the crankcase at the injector pump engine connection

This is what I was concerned about. They use this engine in sime Massey Fergusen tractors, Hesston mowers, etc. Hoping the new injectors fix the issue, though. 

[KFhunter]

not familiar with Sisu, but aren't your injectors outside of the valve cover?   
So you'd see a leaky injector as it would run down the outside of the block and not make engine oil.

I find it very unlikely two injectors would go out at the same time.


The p pump uses engine oil to lube the cam and internals of the pump, diesel is probably getting in there.   If the pump is on its last leg, that would explain multiple cylinder misfires at low idle speed  (lack of fuel pressure)

that's a long run to be washing cylinders, best of luck 


A high pressure fuel gauge would help here, also low side fuel pressure. 

[Skillet]

not familiar with Sisu, but aren't your injectors outside of the valve cover?   
So you'd see a leaky injector as it would run down the outside of the block and not make engine oil.

I find it very unlikely two injectors would go out at the same time.


The p pump uses engine oil to lube the cam and internals of the pump, diesel is probably getting in there.   If the pump is on its last leg, that would explain multiple cylinder misfires at low idle speed  (lack of fuel pressure)

that's a long run to be washing cylinders, best of luck 


A high pressure fuel gauge on the common rail would help here, also low side fuel pressure.

They are outside the cover. If I understand what I'm hearing from others, the injectors might be stuck open, over fueling those two cylinders and pushing fuel past the rings?  When on the back deck during the run to town, I could definitely smell unburnt diesel. 

My fear is that it's the pump leaking, but I'm making a $1k bet that the injectors being shipped from Ontario will get me fishing. I'm hoping it was the fuel from the remote fuel dock that precipitated the two injectors failing together. If not... The pump is not readily available through the AGCO dealer network at this time.

I'm already thinking about having to knock off early this year and do an inframe over the winter if I did real damage. 

[KFhunter]

That makes since, so I'd want to know where the debris came from.   If you have good filtration it should have been pulled out of the fuel before it hit the pump, if the pump is going out maybe debris came from the pump and stuck the injectors open. 

In any case that doesn't help your run back to town and seeing a mechanic.



I'd change injectors anyways if the pump went out, not too big of a gamble there.

[7mmfan]

If you blow that engine up you'll have to up your KABOOM count to 2.