LLY Injector Problem

[Javy]

Hello,
I own a 2005 LLY truck.I've had 2 injectors replaced within
10k miles of each other.Now at 50k,My truck is experiencing
same symptoms as other injector failures.If any of you have experienced a failing injector, you know what I mean.It often clears up after a few miles.ESPECIALLY when you drive to dealer.As you might know,when injectors start to fail,even
though "check engine" light comes on,computer does not
record an injector failure.
YESTERDAY,as I said,my truck was running on 7 cylinders
so I limped it to dealer.AS I DROVE INTO PARKING LOT,
injector cleared up.THEY SAID ENGINE WAS MISFIRING WHICH CAUSED "CHECK ENGINE" LIGHT TO TURN ON.
THEY SAID ENGINE WAS FINE NOW AND CHARGED ME $80
TO RESET "CHECK ENGINE" light.Even though I bought extended warranty.IS THIS UNBELIEVABLE ?????
I would appreciate any comments.I'm in So Cal
Thanks

[DmaxMaverick]

Sounds like the #2 and/or #7 injector harness is needing attention. It's a known LLY issue with a TSB to address it (I don't have the # handy). The repair will be covered by the 5/100 Diesel engine warranty, even if you don't have an extended. Try another dealer.

[Javy]

Are Duramax slugs numbered the same as small blocks ?
Odds on left and evens on right ?
The correct way, not like fords.
#2 is front right and #7 is left firewall ?
Is there a common wire with these 2 cylinders or what is the connection ?
Thanks

[DmaxMaverick]

Cylinder banks are opposite that of SBC's. Odd on the right (US passenger side). The cylinder banks are staggered opposite, so the #1 will be most forward, like other GM V8 engines, but on the other side.

The harnesses aren't common, just in the same location on the heads. The L/R heads are the same, and interchangeable, just like other GM V8's.

[Javy]

MAV,
You are familiar with an injector going bad,correct ?
My wife and 2 friends are on the road to Tennessee as we speak to pick up
a 1937 Chevy 1 1/2 ton Beer truck I bought on e-bay.What does that say about my wife ???

[DmaxMaverick]

Familiar? Just last week I was under the valve covers for another set of injectors. The LB7 is different than the LLY, but injectors none the less. What you described does not sound like a failing injector. They don't turn on/off or clear up. But a failed harness does. I've been listening to Diesel clatter for a long time, and picking out a bad injector is a walk in the park.

Your wife? Gotta winner, especially if the truck is full of beer.

[Javy]

Not to disagree with your diagnoses, but with my LLY,(using BANKS 6 gun with intercooler) I'm experiencing EXACT same symptoms.First time without BANKS
second time with BANKS.By the way, dealer had no objections with BANKS
modifications.Is harness problem visible ?

[DmaxMaverick]

It can be visible, but not always.

Which exact same symptoms are you experiencing?

[Javy]

Very rough idle and no power.
Typical of v8 running on 7 cylinders.
Intermediate.Sometimes by the time I get to dealer,it runs fine.
Until complete failure.
Sometimes "check engine" light comes on,sometimes it doesn't.
You would think computer would save code(or misfire),but it doesn't.

[DmaxMaverick]

If you are seeing the SES lamp, there will be a code in history. You need to pull the code ASAP. The codes will reset themselves, some very quickly, and others take longer. It depends on the class of the code. You should have your dealer install (temporary) a PCM activity recorder. When the problem occurs, you can take a snapshot of what the PCM is seeing/reporting, along with any DTC's present. Another option is to have a code reader handy and pull the code at the time it's happening. When they "reset" your check engine light, what was the code? (no code, no SES lamp) They should have noted it on your work order.

Regarding Duramax injectors:
While it is possible, I haven't heard of or seen them fail electrically. They typically fail mechanically (leak internally or externally). These failures don't typically come and go. May get better/worse, depending on conditions, but will stay once they show up. The symptoms can vary, including engine knock (like a rod or piston pin knock, or a miss), exhaust smoke, lack of power, vibration, rough running at/near idle, higher EGT's for the respective bank and/or heavier than normal clatter. Mechanical failure won't generally set a DTC until the failure is excessive (high return rate or loss of pressure from bypass). An electrical failure (like the harness with an open circuit) should set a code nearly every time, whether you see it or not.

[Javy]

THANK YOU MAV,
The symptoms you describe are exactly what I'm experiencing.
My wife is just passing Little Rock and truck has acted up twice so far
but cleared up.
Thanks again.

[carco]

My LLY had loss of power and blue smoke excessively. Would come and go but as time went became more consistent. Was the inj harness. Repair performed, no problem since. bob............