2004.5 fuel dumping in oil

C

curtism

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Mar 13, 2010
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i was pulling a small trailer, truck seemed a little low on power but not bad, EGT's a little high but not over 1100ish. pulled over to eat and i have oil soaked down the side of my truck and covering the bottom, and i have a lot of "blow by" out of the ccv tube, (none previously but i'm not sure it isn't just smoking because of the fuel and oil being so high) I drain my oil and it has 6 gallons of oil/fuel in the crankcase, and it had been blowing out the CCV tube. once i get it home i pull injectors and take them for testing. they tell me all tested out of spec but nothing extremely bad, no cracked body. they did say that my #4 was stuck open but popped back and worked the same as the other 5 after starting the test. because i wanted to make sure i didnt melt anything and waste money on a full set in case i want to put a different motor in i replaced only the #4 injector and the #6, after replacing them i have the exact symptoms. (smoke from ccv, and filling with fuel still) i want to mention also that i have ZERO smoke from my exhaust and the truck starts and idles and seems perfect. please help me with some ideas!!
 
The only thing left to check is a leaking CP3, a cracked cylinder head or bad injector body o-rings.
 
i would run a dye in the fuel, have the valve covers off, use a black light, let the engine run and see if anything is coming from up top, if nothing, then pull the pan and see if you can see any fuel coming from the cp3, removal of the front cover would probly also work
 
who knows why a head might crack, heat maybe. To check the fuel pump seal, you need to look at the front side of it and then pressurize the fuel system to 30-50 lbs and see if you can see fuel coming out around the seal. The only time i have seen a head crack was with an ISX and it cracked from the injector bore to the hold down bolt hole, dont have any idea why, but it did. Before i would go through all the work of dropping the pan or front cover, i would really look hard at seeing if fuel is coming up from around an injector. $.02
 
pull plug in timing cover and cp3 nut and use a mirror to look at seal. What psi fuel supply are you using to your cp3? never seen a cracked head putting fuel in oil, not to say couldn't happened. I would bet cp3
 
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smokeisfun said:
who knows why a head might crack, heat maybe. To check the fuel pump seal, you need to look at the front side of it and then pressurize the fuel system to 30-50 lbs and see if you can see fuel coming out around the seal. The only time i have seen a head crack was with an ISX and it cracked from the injector bore to the hold down bolt hole, dont have any idea why, but it did. Before i would go through all the work of dropping the pan or front cover, i would really look hard at seeing if fuel is coming up from around an injector. $.02
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Correct (CP3), Except the engine must be running, the internal pressure is much higher then 50psi when running.

There is a weep hole for leak between lip seal and front seal in the CP3, but in general it gets plugged and leaks down the font engine cover into crankcase,ugh.
 
You could pull the valve cover and start the engine. Watch for leaks around the injectors. If you don't see anything pull you fCA plug off and it will go to full rail. Usually you will see a leak if there is a injector issue on the oil side. Just don't let it run for too long with it unplugged.
 
TCDiesel said:
Correct (CP3), Except the engine must be running, the internal pressure is much higher then 50psi when running.

There is a weep hole for leak between lip seal and front seal in the CP3, but in general it gets plugged and leaks down the font engine cover into crankcase,ugh.
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I'm not arguing, but that lip seal wont be able to seal what ever rail psi is, it just seals what ever pressure that is inside the pump for lubrication and what ever pressure is there to feeds the pistons for the rail, is that right or not?
 
smokeisfun said:
I'm not arguing, but that lip seal wont be able to seal what ever rail psi is, it just seals what ever pressure that is inside the pump for lubrication and what ever pressure is there to feeds the pistons for the rail, is that right or not?
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The internal pressure is controlled by the COV when truck is running lifted by the GP so its much higher when pump is running, the rail is fed by the high pressure side of the Pump, they are entirely separate circuits. when the high pressure side leaks into the low pressure side thats when the pump becomes a window....ugh.
 
TCDiesel said:
The internal pressure is controlled by the COV when truck is running lifted by the GP so its much higher when pump is running, the rail is fed by the high pressure side of the Pump, they are entirely separate circuits. when the high pressure side leaks into the low pressure side thats when the pump becomes a window....ugh.
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IC, but fuel could still run out the front of the pump even if the high pressure wasnt leaking into the low pressure circuit right? Also, what is the internal low pressure made by the gear pump? If it is only 100-150, you could still pressurize the low pressure side of the pump with out running the engine, just use compressed air at the inlet of the pump. I am basing alot of what i know about common rails and how to trouble shoot them off of the system on the new Detroit DD series, i know that is a bosch system and cummins has there own, but i try to find similarities between them. Thanks for the info and patience.
 
i have determined that i dont have a cracked injector. would it be possible to put that much fuel in the oil from being a cylinder problem? as in melted piston, broken rings or should i go ahead and pull the cp3?
 
curtism said:
i have determined that i dont have a cracked injector. would it be possible to put that much fuel in the oil from being a cylinder problem? as in melted piston, broken rings or should i go ahead and pull the cp3?
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I don't see that much Fuel for such short period of time to enter the crank case without injector failure, Others may chime in with personal experience (Unfortunately)
 
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