8V71N fuel in oil HELP!!

[Shaunc]

My oil samples came back and I have 5.7% fuel content in the oil.

All my injectors were replaced just at my last oil change so i doubt it could be a leaking injector ( not ruling it out)

I am not sure what to do or where it could be coming from. I looked at bunch of forums including the ones for buses etc and not to much help there.

Any one have any ideas?

 

[Pascal]

There has been a number of posts about the poor quality of some new injectors. Don’t forget new stands for Never Ever Worked


I also recall mention of a leaking fuel pump being a cause for fuel in the oil. I always smell the oil when checking it ... whether in boats or cars

 

[racclarkson@gmail.com]

Leaking or fractured jumpers come to mind.

 

[davidwigler]

That’s what happened to me after a tune up.

 

[davidwigler]

Leaking or fractured jumpers come to mind.

That’s what happened to me after a tune up.

 

[bigbill]

detroit recommends changing the jumpers when changing the injectors.... thats where i would look first

 

[SKYCHENEY]

Time to pull the valve covers and look for a leak.

 

[Shaunc]

Thanks guys

I ordered a new fuel pump today.

Let me change that out and then test oils samples again. If not resolved, then time for valve covers to come off.

So if i hear right it there are 3 ways to leak fuel into oil. Injectors, fuel pump or jumpers?

 

[Captain Ralph]

It's not the fuel pump. There is a weep hole for the fuel to leak out on the engine, not in the engine. If you did not use new pipes,,,,,You have a bad fuel pipe.
Always replace the pipes when working on injectors. Cheap insurance against things just like this.
The next time you have a pipe in your hand, look at the matting surface. A crush area meant to be used ONCE..

I keep an inventory of pipes, even if I have to just chase one injector, I will know it is correct when I put the bonnet on.
There is also a proper fuel tube tool to help snug them down correctly with out rounding the hex corners off.
As a proper tool for the push rod adjustments and plunger height.
Was this a DIY or some (supposed) DDC tech?

 

[racclarkson@gmail.com]

Thanks guysI ordered a new fuel pump today.Let me change that out and then test oils samples again. If not resolved, then time for valve covers to come off.So if i hear right it there are 3 ways to leak fuel into oil. Injectors, fuel pump or jumpers?

Is that a good plan? Not to me. Hook up a priming pump and shutoff the fuel return to pressurize the fuel system.

 

[MikeMck]

It's not the fuel pump. There is a weep hole for the fuel to leak out on the engine, not in the engine. If you did not use new pipes,,,,,You have a bad fuel pipe.
Always replace the pipes when working on injectors. Cheap insurance against things just like this.
The next time you have a pipe in your hand, look at the matting surface. A crush area meant to be used ONCE..

I keep an inventory of pipes, even if I have to just chase one injector, I will know it is correct when I put the bonnet on.
There is also a proper fuel tube tool to help snug them down correctly with out rounding the hex corners off.
As a proper tool for the push rod adjustments and plunger height.
Was this a DIY or some (supposed) DDC tech?

Thanks Captain
A valuable lesson as I'm about to pull and bench test the injectors on one of my 8-71. Unless of course there is a better way to find a bad injector.
Mike

 

[Shaunc]

Thanks Ralph

The injectors were replaced by a DD tech who rebuilt my port engine at purchase. He rebuilds and services DD only so I trust him. He is one of the the few DD guys I trust.

The trouble is that he is across the state on the east coast and I am on the west coast and its not easy for him to get here.

I dont remember if he replaced the fuel lines.
I will reach out to him today and ask.

 

[ageless]

Thanks Ralph

The injectors were replaced by a DD tech who rebuilt my port engine at purchase. He rebuilds and services DD only so I trust him. He is one of the the few DD guys I trust.

The trouble is that he is across the state on the east coast and I am on the west coast and its not easy for him to get here.

I dont remember if he replaced the fuel lines.
I will reach out to him today and ask.

curious who your mechanic is
definitely start with the jumpers

 

[rsmith]

The first 46cHP with 8/92’s had a internal engine fire due to the jumpers leaking. As I understand fuel oil mix got sucked into the turbos and ignited. Not something to mess with.

 

[Captain Ralph]

Thanks Captain
A valuable lesson as I'm about to pull and bench test the injectors on one of my 8-71. Unless of course there is a better way to find a bad injector.
Mike

Why do you think you have a bad injector? Smoke color? Poor performance?

Without sending the injectors to a shop for popping, Your probably not going to get satisfying results from a home bench rig comparing injectors.

However, this are two ways to test for a dead lung on your running engine.
The clean way is a thermal gun pointed to every exhaust finger from the head to the exhaust manifold. At idle, this may not be the most perfect to ensure all injectors are matched but if there is a cold lung, this will help. Under load at 800 to 1000 will show up better. Without a IR gun? Try a crayon (old street rod trick), the wax crayon should melt at the same rate on each exhaust manifold finger.

Like pulling spark plug wires on da ole Chevy V8, you can cancel out an injector on an idling Detroit. Valve cover off, lil goose necked crow bar, find some traction and hold the the injector tappet down while idling. The idle will sound different if it is a good lung. Sound the same if a bad lung.
When you suspect a dead injector, rotate it with a good one a couple of lungs away. Test these two again at idle, if the problem moves with the injector, it's the injector that is at fault.
Same lung, bad lung (usually valves).

Hope this helps.

 

[MikeMck]

Why do you think you have a bad injector? Smoke color? Poor performance?

Without sending the injectors to a shop for popping, Your probably not going to get satisfying results from a home bench rig comparing injectors.

However, this are two ways to test for a dead lung on your running engine.
The clean way is a thermal gun pointed to every exhaust finger from the head to the exhaust manifold. At idle, this may not be the most perfect to ensure all injectors are matched but if there is a cold lung, this will help. Under load at 800 to 1000 will show up better. Without a IR gun? Try a crayon (old street rod trick), the wax crayon should melt at the same rate on each exhaust manifold finger.

Like pulling spark plug wires on da ole Chevy V8, you can cancel out an injector on an idling Detroit. Valve cover off, lil goose necked crow bar, find some traction and hold the the injector tappet down while idling. The idle will sound different if it is a good lung. Sound the same if a bad lung.
When you suspect a dead injector, rotate it with a good one a couple of lungs away. Test these two again at idle, if the problem moves with the injector, it's the injector that is at fault.
Same lung, bad lung (usually valves).

Hope this helps.

It helps.

Lots of white smoke at start up then disappears at operating temp. 4500 original hours.

Performance? It's a 1972 45C fast to her is 14knots. I run her at 8 to 9 knots 99% of the time. diesel discipline.

I'm in Ensenada Mexico and the tuna fleet runs out of the harbor so lots of guys that get DD and shops to test and or rebuild injectors. Inframe rebuilds are pretty reasonable as well.

Thanks for the advise.
Mike

 

[dottieshusband]

If some mechanic suggested the fuel pump as the problem, you need a new mechanic. The fuel pump is mechanically driven off the governor... no way for fuel to enter the crankcase practically. Take the valve covers off, close the feed and return valves, and pressurize the system. Most likely you have leaking jumpers.

 

[Captain Ralph]

I stepped in it and continued with a second & different question. Apologizes to the OP.

MikeMck
Open a new thread, copy/past your question and I'll fill you in more. We will get you fixed.
Later an admin can strip our trompings here.

,rc

 

[Pascal]

curious who your mechanic is
definitely start with the jumpers

I may be getting old but back around 2005/2006 I had diesel In the oil of my port 8V71N and I clearly remember someone here suggesting the fuel pump. That’s why I mentioned it earlier in the thread. I changed the oil and oddly enough I never had diesel in the oil again ...

 

[osprey]

Almost certainly the fuel injector jumpers, they are finicky things, need to be positioned, aligned and finger tightened before final torque. Do not over tighten. should always replace with new, but that is no guarantee . When you remove the head cover, check carefully around the injector, the fuel that is leaking will clean the surrounding area of oil. fairly easy to remove line from fuel pump, plug line to cooler and pressurize. you can also run engine with cover off, although a little messy. good luck, can happen to anyone. Pete