Fuel in Oil....

AKDuramax

AKDuramax

Rice-Burner Burner
Joined
Aug 10, 2007
Messages
145
So last Sunday morning, I started my truck with my autostart, and let it run for about 10 minutes before I went outside. When I went out an got in my truck, I noticed it was idling really rough, looked at my oil pressure gauge, and it was reading under 20psi, so I shut her off, popped the hood, and checked my oil. Wouldn't read on the dipstick, cause it was mostly diesel. Had a buddy come over, and we towed it to my shop. Pulled it in, drained the oil, and probably got about 9 or 10 gallons of fuel/oil out of it. Truck has ran great without any hiccups. I change the oil every 3k and fuel filter probably every 2 oil changes. She just rolled 107k miles, and has ran like a champ since we bought her new. I was thinkign that an injector might be stuck open? Or an o-ring or something blew? Any ideas??

Kevin
 
I just had the same thing happen on my 06 cummins after I installed new nozzles. I removed the valve cover and started it up. We found injector #1 was misting fuel out right were it goes into its bore in the head. I removed it and brought it to a diesel injection service shop. They put it on a test bench and found that at about 10,000 psi it was fracture right below the hold down. You might also have a loose or fracture connector tube.
 
Yeah, I miss my cummins, the injectors look like they're gonna be a pain to get to on this engine. Ugh. I put new oil in it and fired it up and ran it for a few minutes...Good oil pressure, doesn't sound like it's missing on any cylinders. Dont know how to go about doing a cylinder contribution test on a common rail...?
 
And we dont have any injection shops in town...So i either have to send them to Anchorage, or Seattle...Ugh.
 
Injector took a poop most likely. It's not going to be fun on the LB7
 
Yea bad injector..there not fun at all to take out.....but we can test your injectors for ya and tell ya which one is bad if you wanna send them to us.....
 
If you can find someone with a Tech II scantool run an injector balance test with it. It will locate which cylinder is the problem. If you are the original owner there maybe a warranty on the injectors as GM up'ed the warranty to 200,000 miles on the 2001 - 2003 LB7 motors. Also there are return fuel lines under the valve cover that maybe leaking but it's most likely and injector or two.
 
I'm not the original owner, but my boss is. I know a guy with a Tech II scan too at a shop i used to work at. Now, if it is a bad injector or two, should i say to heck with it and replace all 8? It doesn't look like it's gonna be fun egtting down to the injectors...
 
If your plan is to keep it I would do all 8 but I would also see about getting the warranty on the injectors if it applies, as a set of 8 injectors is around $3500 not installed from what I remember.
 
Dang, thats alot of dough. Hope the warranty will work. Im just confused, because when i run the truck, it doesn't run rough or sound like it's missing on any cylinders...i'll just have to put it on the scan tool.
 
If the cylinder balance comes out good then you may have a leaking return line under the cover or a CP3 leaking fuel out the front seal. The only way to find out is to remove a cover and start it up and watch it.
 
Balance test came out good, so looks like i'm pulling the valve covers. Seems to be alot of important stuff to run the engine, that i gotta remove to get the covers off?
 
So, my injectors are good, and according to the scan tool, my rail pressure is in check and so is fuel pressure. That would narrow it down to the return side, right?
 
Just because the truck passed a balance test doesn't mean that one of the injectors didn't pop. There is a little check ball half way covered by the solenoid hold down nut that will pop out thus pushing fuel into the crank case. Yes a balance test will show + or - on how but it might not show up. And all and all they are not that bad to replace. Once you have the crap out of the way its rather simple.
 
Yea, it's the crap that's the problem. From wiring to valve covers.
 
Just because they pass the balance test doesnt mean they are not leaking. You can get remans for around 150 each. As big of a bastard as they are to change i would strongly recomend all 8 at once. You have to be careful pulling them and hope the sleeve dont come out of the head with the injector. Resealing the sleeves is time consuming.
 
Once the upper valve cover is removed you can reinstall the injector lines and start the engine. It will toss some oil around but you can look for a fuel leak that way. If you cannot find one then go to the other side and repeat. If both sides are good and no fuel leaking into the oil area then it's the CP3 seal leaking and will require a new CP3 to be installed.
 
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