LB7 Low rail pressure cause smoke?

[Rustorbust]

Injectors were done about 30,000 miles ago at the dealership under warrantee. CP3 was done about 20,000 miles ago. I have checked the balance rates and they're all within spec. The rail pressure at operating temperature is hovering around 4100 to 4200 at idle (I thought LB7's we're supposed to be up in the 5000 PSI range). I'm checking all this with an app on my phone and with one of the Wi-Fi OBD2 connectors. I'm not able to check commanding pressure though.

Once It gets up to temperature it's smokes white smoke pretty good. Can the lower rail pressure have anything to do with it? The truck also has an airdog 100 lift pump on it.

I have checked the oil and it's not making any and it doesn't show any signs of diesel in the oil.

Any help I appreciate.

 

[2004LB7]

I have ran mine down to 3500 psi without any smoke.

What is the timing?

 

[JRein]

What's your main injection rate? If it's not around 8mm3 the ecm could be pulling fuel from all cylinders

Sent from my SAMSUNG-SGH-I747 using Tapatalk

 

[Rustorbust]

Here's a screen shot of what I'm seeing

 

[Brent@LDS]

When has the fuel filter changed last?

 

[Rustorbust]

Changed the filter out yesterday actually.

 

[Brent@LDS]

Injectors are probably failing on the return side or leaking nozzles.

 

[Rustorbust]

Yea that's kinda what I didn't want to hear. Was hoping it could possibly be something simpler like a fuel pressure regulator or something. Anything I should do or can do to troubleshoot it further before pulling the trigger on new injectors just to rule out other potential problems?

 

[2004LB7]

Can you get a screen shot of the balance rates of all injectors? And see if you can find the commanded or desired fuel rail pressure, that will help a lot

 

[THEFERMANATOR]

Federal emission lb7's run 35 mpa stock, roughly 5100 psi. Cali and ne emissions trucks run 30 like lly, lbz, and lmm which is roughly 4200 psi. Not all scanners do the conversions accurately, even my V2 in bbx mode isn't that accurate compared to when scanning using v7. Depending on your tuning and ambient remps, yes it can cause white smoke at idle. I tried turning mine down to 30 when I had stock injectors with low miles trying to make a quiet idle tune at 600 rpm's. It would idle for about 10 seconds in 50 degree temps, then the white smoke would start. By the time it had ran a minute, it was whiting things out with smoke, flipped my dsp switch to a tune that was identical except idle pressure was 35, and the smoke stopped immidiately. I ran it at 35mpa at idle, and it never white smoked again for 50+k miles until #2&8 went, and it started blue smoking at idle.

 

[Rustorbust]

Well my truck is a completely untouched stock California emissions truck so with what you said I'm guessing at idle 30mpa or 4200psi at operating temp sounds about right. I drove it some tonight and rail pressure is going to 23xxx at 16lbs of boost so I'm pretty sure the regulator and cp3 are functioning properly. It's leaning more and more towards injectors.