Chevy/GMC Duramax 01-04 LB7 Discussion of Chevy and GMC Trucks with LB7 Duramax Turbo Diesel Engines

How to tell if injectors are going out?

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Old 03-08-2010, 03:56 PM
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Default How to tell if injectors are going out?

If my injectors are not performing properly, what are all the signs to look for? I haven't had any leaking coolant, no fuel in oil that I can see, no weird changes in oil pressure, and fuel economy still seems to be normal when cruising and driving around town. But, to me, my truck sounds 'rough', not as smooth as it did before. I've been bleeding the fuel filter regularly and running 2-stroke but it still doesn't sound quite as smooth. Any thoughts?
 
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Old 03-08-2010, 07:50 PM
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slight cylinder imbalances and valves out of spec after so many miles?
 
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Old 03-09-2010, 12:33 AM
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Some signs of fuel injectors failing are. whiteish smoke out of the exhaust at idle or when driving, surging, diesel in the oil;you wont see it unless you drain the oil and you get about 5 gal worth. You will smell the diesel if its in the oil. Inector ratle, bad balance rates, loss of power and bad fuel milage.

- My injectors were failing and the only sign that I got was smoke. I thought the power was still normal. but once I replaced them it felt like a whole new truck.

-If your really concerned take your truck to someone that has EFI live or the dealer and have them check your balance rates.

- try running Power Service fuel addivitive that always quited down my truck.
 
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Old 03-09-2010, 09:28 AM
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Yeah I just noticed the last few weeks it sounds louder when the engine is cold. It was running smoothly once warmed up on my way to work this morning, but I've still noticed that it hasn't been consistent. I'll try and find someone who can check the rates for me, otherwise it looks like it might be time to bend over and head to the dealer.
 
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Old 03-10-2010, 05:23 PM
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Bump. No one has had bad injectors in a duramax before?

I have 0 smoke, just a little louder when cold and warming up. It smokes as usual when it's cold outside for the first few minutes but after that seems fine. Power still seems good too. I notice though when I accelerate the instant economy monitor will drop down to 2-5mpg without being at WOT... Anyone else seen numbers that low?

I haven't taken it on a road trip in a while, I'll have to see how it does on the highway again. Truck now has 140,xxx miles on it and according to the history report when I bought it the injectors were replaced in 2003 early on from what I recall.
 
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Old 03-10-2010, 10:41 PM
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drop some 2 stroke in the tank and see if it quiets down
 
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Old 03-10-2010, 11:09 PM
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one thing i noticed when my injectors were getting crappy they did make more niose than usual, but then again my buddy's lly his injectors are niosy as hell and his are fine
 
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Old 03-11-2010, 09:35 AM
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Well guys, I'm confused as hell now. It warmed up to 6C/42F yesterday and she ran as smooth as new, just like a dream, right from idle up to WOT 70mph. No complaints at all. Maybe it's a cold weather thing?
Again on the way to work this morning, ran fine and smoothly. Maybe I just wasn't warming the engine up enough or had some crap in the fuel or something...I have no idea. I checked the oil last night and it did not smell of diesel, looked and felt fine, coolant level may be down a tad from the cold level mark, fuel filter has been bled consistently and I've been running the 2-stroke all along. And again, only smokes when it's cold right at initial startup, but once the temp gets up a little the smoke goes away. I took my uncle for a ride in it a couple weeks ago and he just thought I was paranoid.
 
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Old 03-11-2010, 10:53 AM
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Is an injector check already done?
It consists of checking:
- spray pattern
- start and spray pressure
- correct noise when released
- correct valve operation( dripping)

Most Diesel services can do that.
Have in mind that humidity and outside temperatures play a big part in that game.




It seems that you really need an engine heater, hehehe
 
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Old 03-11-2010, 12:50 PM
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Stinker, on the lb7 duramaxes the amount of time required just to even pull those boogers out is makes you just want t buy brand new ones, ill definitely no just pull them out just to look at the it takes 8 hours
 
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