Failed Injector/s

[Iceman3005]

Need a little help, one or many of my injectors are starting to fail, fuel getting in to oil. Where should I get injectors from, should I get new ones or rebuilt ones. I have not done very much research on 6.2's injection system, only the cummins engine is all I have ever researched or worked on (for the last 7 years), and I am pretty sure most of the places that sell good injectors for the newer trucks/engines don't mess with the 6.2 injection system. I got on some site and have seen 8 injectors for about $150-250 for rebuilt, some say they use genuine bosch parts and some don't. If I buy new there about $450-850, the lower end seems to be the marine injectors and the higher end seems to be bosch. Here is to sites I found for new injectors: SSDiesel Supply :: GM 6.5 TD Specialists : Fuel Injection : Heath Diesel, On-line Store

 

[ODdave]

How is the fuel getting into the oil? That much wash down in the cylinder?
Shure its not the seal on the pump shaft???

 

[Dr.Jay]

How is the fuel getting into the oil? That much wash down in the cylinder?
Shure its not the seal on the pump shaft???

I was thinking the same thing. Pump shaft seal leaking.

Reman Injectors are available for around $50.oo each. Plus the core charge from most of the automotive parts stores

 

[Iceman3005]

I'm not sure how much is getting in there, normally the oil level drops slowly between oil changes, the truck sat for about 8 months while I rebuilt front axle. Once I started driving it again my fuel mileage went from 22 mpg down to 16mpg, the oil level started to rise and I could smell a faint hint of diesel on the dip stick after the third/fourth week of driving. After about a four weeks of driving a rod started to knock, I changed the oil and filter that day (last Friday 4/13/12), and the oil was like water in consistency, after I changed the oil the knock went away, but the oil became black almost immediately after oil change, usually it takes a couple of hundred miles. I also changed the fuel filter and air filter, I usually change the fuel filter every 6000 miles, it only had 2000 miles on the fuel filter but I changed it anyway. Where is the fuel coming from and how much, well really not sure but only thing I could think of was injector/s going bad.

 

[Iceman3005]

It starts very easily so it probably isn't a bad injector or it would start hard and run poorly, like you said Dave maybe pump seal. Probably only way to find out is take front timing cover off?

 

[Iceman3005]

Thanks Dave, sometimes we need to just step away from the problem and ask a question or two, got me thinking it could also be the lift pump leaking. Dave do you now where I could get my injection pump rebuilt or should I just buy a new one if it is the seal?

 

[ODdave]

Diesel equipment in poterville is who I use.

 

[Dr.Jay]

Thanks Dave, sometimes we need to just step away from the problem and ask a question or two, got me thinking it could also be the lift pump leaking. Dave do you now where I could get my injection pump rebuilt or should I just buy a new one if it is the seal?

Good point about the lift pump possibly leaking. I normally work on more modern Diesel engines that do not have them so i forgot to suggest it as the possible cause of your fuel in oil problem.

In my experience, when troubleshooting a problem it is usually best to check the least expensive item to replace, first.

 

[ODdave]

Oh ya, Definatly check that lift pump as well !!!

 

[Hasdrubal]

Second on that lift pump. Even in the installation instructions it says that a ruptured diaphragm can allow fuel to contaminate the engine oil. Make sure that you get an AC Delco one, not a Carter, they are total ****.

 

[Stonepicker1]

on the lift pump.

 

[tbearatkin]

Some good hints here on replacing the mechanical pump.

http://www.steelsoldiers.com/cucv/57964-fuel-pump-replacement.html

 

[Iceman3005]

Bought the lift pump, but my fuel MPG seems to be up, filled up on Saterday and was getting 17.5 up from the 16 I was getting, I have driven 120 miles since then and fuel gauge is just barely below the full mark, think I might be in the 20 mpg now. No more extreme back pressure coming out of oil fill tube, I'm wondering if my fuel return line was clogged creating back pressure on the fuel system. I have the lift pump on hand and ready if I see any more problems. May still have a problem but seems to have gone for now, will now more after I drive a couple of hundred more miles. Oil has cleared up a little also, looks more of a brownish now then a black, will change again in 500 miles.

 

[Barrman]

A clogged return line on the IP will cause the engine to not run.

 

[Iceman3005]

Went and bought a "Haynes Techbook Diesel Engine Repair Manual"

It list in the diagnose section as follows:

Oil diluted:
Defective fuel supply pump=?
Defective injection pump=?
Broken or worn piston rings=might run poorly and start hard

Excessive fuel consumption:
Blocked air intake=old air filter was ok, put new one in anyway
Excessive exhaust back pressure=doesn't explain fuel in oil
Blocked fuel return line=?
Blocked fuel line or filter=changed
External fuel leak=no visible leaks
Clogged or defective injection nozzle/s=?
Defective fuel supply pump=?
Incorrect fuel=I know the fuel is correct
Defective injection pump=?
Leaking head gasket=blew head gasket, put new in with stud kit
Broken or worn piston rings=would run poorly and start hard
Leaking valves=would run poorly, doesn't explain fuel in oil
Low compression=would run poorly,start hard
loose timing chain=would run poorly, doesn't explain fuel in oil
Advance timing=mine is advanced but runs better
Retarded timing=read previous statement
Worn camshaft=doesn't explain fuel in oil


The truck starts very easily and runs great, has plenty of power (for a 6.2).

@Barrman I thought of clogged fuel return because it was mentioned in the Manual.

The mileage got better immediately after fuel filter change.