- Hi I'm Nick Priegnitz, with Duramaxtuner.com
and today's Diesel Insights is gonna be on the LB7 injector.
Commonly referred to as the worst RPO for injector failure.
I think we need to dive into it a little bit
and talk about what's going on here.
(energetic rock music - yeah!!!)
So we talked to most of the experts
about LB7 injector failures, what they're gonna come back
to you, tell you is that it's caused
by fuel system contamination.
Poor fuel system maintenance
or fuel system contamination is gonna lead to water
or contaminants or dirt getting into the fuel system
and you have fuel under 23,000 psi here,
so very high loads in the system,
you have this contaminants moving through the fuel system,
you know you're gonna cause erosion,
poor sealing on internal metal parts, pitting,
all sorts of bad things are gonna happen
inside the injector when you have contaminants
in the fuel system.
Next cause of injector failure is gonna be
internal wear caused by low lubricity,
so similar to contamination but this time
because we don't have enough lubricity in the fuel system.
If you have this low lubricity, you have again,
wear in the fuel system prematurely
and you lose consistency, you lose precision,
you lose the ability for the injector
to do its job properly.
Next failure in the injection system is gonna be
more on the top side of the injector,
so this is where the fuel line seats on the injector
where that torque takes place, it's a torque to spec setup.
Oftentimes those are over torqued
or those injection lines are reused.
When that happens you have the potential to have leaks
on the high pressure side of the injector.
When you have those leaks on the high pressure side
of the injector that fuel goes right
into the crankcase, again, losing performance
in the injection system fuel in the crankcase.
It's all a bad situation, cascades into much worse things.
Okay and the last major cause of an LB7 injector failure
is gonna be more of a factory issue.
So 2001 - 2007 the ball seat which is an internal part,
sealing the injector, was not hardened.
In 2007 they went to a chrome-hardened ball seat,
if you have one of these early injectors
you're gonna get less life out of it
just because the day-to-day use the injector,
the hammering that takes place there, the high loads,
you're gonna have erosion on that ball seat.
Okay, so, how can we diagnose it?
You commonly hear guys refer to the balance rate test.
This is an easy test to perform and it's all electronic,
you just plug it into any tube port
you can look it on Edge CTS EFILive tech two etc.
You'll see eight balance rates
and these numbers are indicative of per cylinder
how much fuel is added or subtracted in mm3
which is a volume to maintain a consistent
crank shaft revolution, so, a smooth idle.
If you see balance rates that are outside of 4 mm3,
that's supposed to be an indication to you that you have
an issue in the fuel system, probably an injector problem.
Okay, bad balance rates can be caused
by other things as well, poor cylinder performance, valves,
a whole host of other issues there
but balance rate test is gonna give you
a pretty good indication on LB7 of whether
or not you have injector problems,
again, plus or minus four in park
or neutral is the number you're looking for.
In my experience, if you're getting
past two and a half or three, you're probably getting there.
Fuel in the crankcase is gonna cause bearings
to get wiped out it's gonna cause all sorts of issues
in the engine, we want to find fuel in the crankcase
as soon as possible, it's indicative
of a high pressure fuel leak, in the fuel system,
again the injectors are under the valve covers,
the whole fuel system really is
under the valve covers there, so if you have fuel
in the crankcase, there's an issue.
Long crank when hot again leak down high return rates
taking a while for the injector to come back to life
that's an indicator to you.
Haze at idle, this is easy to see on trucks on the street,
if you see a truck on the street and near at a stoplight
and you see a white haze coming out at idle
and it smells like putrid fuel, like unburnt fuel,
that's probably an LB7 that needs injectors.
Again, none of these in and of themselves are gonna
be directly it needs injectors but if you see
all these issues together, you're probably getting there.
There's further diagnostics you can do of course
but those are gonna be the easy ones.
How can you fix it?
So, fuel system contamination,
this is the easiest one to fix.
Change your fuel filter regularly, do not go 50,000 miles
or more on a fuel filter, that's ridiculous,
it's a $40 part, change it every other oil change,
use the high quality filter, change your water separator,
use good fuel, don't get fuel
out of some unknown source because it's cheap.
Okay, injectors are expensive, CP3s are expensive,
fuel system parts are very expensive.
Don't cheap-out on fuel. Use an additive.
If you doubt the quality
of your fuel use lubricity additive.
That additive is gonna help the fuel system perform longer,
stave off those issues from wear, so use an additive,
I'm not gonna recommend one to you but you can find one
make sure it's tried and true and make sure
it has lubricity on it somewhere.
When you replace the injectors, replace the hardlines.
Okay, don't reuse injector hardlines there's plenty
of suppliers out there now who can get you good, cheap,
new hardlines for the injectors and torque them
using a torque wrench, for the love of God,
don't ruin a new set of injectors by hammering
down the injector lines on a new set of injectors.
I think that just about covers it.
I'm Nick this been Diesel Insights we'll see you next time.
Thanks
(energetic rock music)
If you like these videos and you want to learn more,
check out the diesel tuners blog, dieseltunersblog.com
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