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Discussion Starter #1
I have had my lb7 for a little over a year. Lately it’s been smoking at idle really bad and at take off and it smells like raw fuel. I could also smell a little fuel in the oil. I thought it was my injectors so I bought a edge monitor so I could check them and so I can eventually get some tunes done but when I checked them the only one that was out of spec was one for 6 and 2 was not far from it. When I put it in drive none of them was out of spec. Do you think the injectors are bad or could it be something else? I would think with it smoking bad that the balance rates would be further off
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Discussion Starter #2
Also this wasn’t with the engine really warmed up much. Will it make a diff if I have been driving it or not?
 

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GM recommends that balance rates be checked with engine at operating temperature on stock tune.
 

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This should be informative:

 

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Need to check return rates, and re do the balance rate test at operating temp. But when a lb7 is smoking at idle and smells of raw fuel, its 99.99% of the time is the injectors. If you dont know when they were done last or are the originals then its a smart idea to do them. If its making oil then its usually a cracked body or return line issue. You can drip some oil on a paper towel. If its got fuel in the oil the fuel will form a halo ring on the outside of the oil. Source injectors from [email protected] Hes a vendor here. If you have the extra money get the sac injectors. If not the quality reman or new bosch vco arent bad as the old and have been updated. Just make sure you either replace the cups or re loctite them. If the trucks got high miles or rust on the hp lines its a smart idea to get new ones.
 

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Halo example
 

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Discussion Starter #7
Cool thanks for the help. I’m pretty sure it’s the injectors. The guy I bought it from said the guy before him replaced them and the guy I bought it from had put 40k on the truck. I noticed the 2 and 6 injectors were a lot further off than the others so I was thinking maybe either ways the injectors were probably needing replacement. I really can’t afford sac injectors but I was gonna go ahead and get the Bosch reman. I’ve heard that you don’t need to do anything to the cups if they don’t come out, is that not true?
 

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Get ahold of brent at Lincoln diesel and he will get you setup with some quality bosch remans. As far as the cups that personal opinion i think. Some guys say dont mess with them unless they pull out, some say to pull and re loctite them and or get new ones. Im in the 2nd category. Me personally and every good tech i know will take the extra few minutes to reseal the cups even of they didnt pull out.. Use 272 loctite on them. You really dont want to do it twice. Especially if you arent turning the wrenches yourself
 

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Maybe take a look at your air filter and mass air flow sensor. I just went through this with my LB7. The injectors were replaced with Lincoln injectors about 45k miles ago. I run an Airdogg, fuel additives and I'm pretty anal about upkeep and maintenance, But the truck sits a lot and only gets driven about 5k miles a year. It had the classic signs...haze at idle, raw fuel smell. Oil sample came back clean with no fuel or water in the oil. Balance rates were all within spec. So I finally took it to my buddy's shop to have them look at. They put a scanner on it, and see that something is causing restricted air flow. I cleaned my air filter and MAF. To my surprise, BAM...no haze and the truck runs perfect. My MAF was visibly dirty and I hadn't cleaned it in over a year or two. I find it hard to believe that was all it was, but so far everything is good. I had a pretty bad haze that was starting to get embarrassing at intersections. Now that's gone!
 
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Discussion Starter #10
Well I can smell some fuel in my oil and I changed my filter about 3000 miles ago. But I guess it wouldn’t really hurt to see if the maf is dirty. I don’t drive mine much either unless I’m towing my boat or a gooseneck every blue moon
 

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Well I can smell some fuel in my oil and I changed my filter about 3000 miles ago. But I guess it wouldn’t really hurt to see if the maf is dirty. I don’t drive mine much either unless I’m towing my boat or a gooseneck every blue moon
My oil has a slight fuel smell also, but the paper towel test looked good. The best way to check your oil is to send in a sample to Blackstone Labs. I try to do that about every other oil change, its only about $30. It will give you an excellent idea what shape your motor, seals and bearings are in and if there is water or fuel in the oil. Every time I have done it, my report comes back that my motor is in above average condition for the miles it has. Pretty nice to hear that!
 

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Discussion Starter #12
Replaced my injectors and no more smoke and runs a lot better. I installed a edge evolution cts tuner though because my bullydog was messing up and the edge is messing my ecm up I think too. Do I need to get a new ecm?
 

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Is it throwing codes? Edges and bully dogs have always caused me issues on lots of lb7 and lly trucks. Unplug the edge and see what it does.
 

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Glad the injectors worked out for you
 
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