Possible diagnoses

[Johnwi3]

Hey guys, I have a 04 LB7 w/ 153k on it. Have been having the following symptoms over past couple months and trying to see where to start.

- truck seems to load up at idle and smoke. Blue in color smoke, when you run it after idling for extended time it smokes like h@ll then clears up.
- no codes or check engine lights
- have lost fuel prime a few times, mostly when parked facing uphill
- fuel filter is recent
- air filter new
- fuel filter housing rebuilt
- fuel lines new

Have not noticed fuel in oil or loss of coolant. Truck seems to be losing some power but fuel mileage hasn't changed significantly.

I have read a ton of threads and seem to find the common issues of injectors, FPRV, FPR or CP3 pump. I have not even taken to have fuel pressure or balance rates checked yet.

Any thoughts?

Thanks in advance.

 

[ironmax]

Get all of the above tests done and post back your findings. Maybe you live close to someone on here that has a v2 and can scan it for you for some refreshments. Lots of helpful people, that love these trucks lurk here, can't hurt to ask for some more assistance.:thumb:

 

[Longbow06]

Had a GM Duramax Jedi-Master tell me that air leaks in the fuel system can cause similar symptoms. The air leak source may seal up with heat. Not a bad idea to check the balance rates and fuel pressure.

Sent from my SM-G935V using Tapatalk

 

[Brent@LDS]

Hey guys, I have a 04 LB7 w/ 153k on it. Have been having the following symptoms over past couple months and trying to see where to start.

- truck seems to load up at idle and smoke. Blue in color smoke, when you run it after idling for extended time it smokes like h@ll then clears up.
- no codes or check engine lights
- have lost fuel prime a few times, mostly when parked facing uphill
- fuel filter is recent
- air filter new
- fuel filter housing rebuilt
- fuel lines new

Have not noticed fuel in oil or loss of coolant. Truck seems to be losing some power but fuel mileage hasn't changed significantly.

I have read a ton of threads and seem to find the common issues of injectors, FPRV, FPR or CP3 pump. I have not even taken to have fuel pressure or balance rates checked yet.

Any thoughts?

Thanks in advance.

Unfortunately your looking at an injector replacement. Balance rates don't show you the full story on your injector. A return rate test will show you the culprit. Let me know if I can help.

 

[DAVe3283]

Your symptoms sound like classic injector failure. You might also have an air leak, but that isn't causing the white/blue smoke after extended idle.

Lincoln Diesel (guy who just posted) usually has great prices on injectors, and they sell real Bosch remans. I bought a set through him, and would again.

Sent from my FlashScan V2

 

[Johnwi3]

Thanks for the suggestions. My initial fear was injectors but will run thru the tests to confirm. I appreciate the feedback and will post my results.

 

[clrussell]

Injectors.. Put a set in it that are genuine bosch and nothing else.

 

[Johnwi3]

Guys,

Got the fuel line to do a return rate test. Is is accurate to tap off the return line quick disconnect under the hood on the drivers side? If so would it be the 15 second test with a flow of less than 100ml.

Thx

 

[DAVe3283]

I would imagine you could use that and sum all the individual returns together, but then you don't get the full picture. If one injector is totally out of spec, but everything else is tight, it might pass when it should have failed.

It can give you a positive fail, but I don't think it can give you a true pass condition. If it fails, then dig deeper. If it passes, ... dig deeper :joker:

 

[Johnwi3]

What would be the true test way to get accurate readings?