Chevy and GMC Duramax Diesel Forum banner

LB7 problem crossroads

4K views 42 replies 12 participants last post by  houghfarmer 
#1 ·
So, I have a 2001 2500HD Duramax, 273k on the clock so she’s a tired girl. I bought it in November in 2018 after a long search for duramax’s and Finally found this one. It seemed perfect- the owner said the injectors were in balance, extremely clean, and claimed it didn’t smoke. Having the diesel jitters I took his word for it and test drove it, loving every second. Long story short I took it home a few weeks later and loved it, 4 months later I noticed that there was a light haze at a warm idle when I was out and instantly thought the inevitable that my injectors were on their way out. I ran some diesel kleen and it seemed fine, but recently came back. I checked the oil since I never checked when I got it because it was only 200 miles old when I bought it and found that after a paper towel test I had diesel in the oil. I have not checked the balance rates yet but I am assuming I’m due for new injectors and probably new high pressure lines. Would the injectors cause this diesel in the crankcase or is it a fuel line? And should I replace the injector cups when/if I do the injectors? Again, I am not sure what the cause of any of this is, still trying to get my hands on a scanner.
 
#3 ·
I heard the injector body might be the most probable cause, I feel like it is the cups since the previous owner said they were all in balance rates when he scanned it himself. Thinking about doing the injectors regardless since I hear a slight knock, and when I do should I be replacing the return lines in the valve covers as well as the injectors and supply lines?
 
#5 ·
The cups wont leak fuel. The cup is just a piece that goes into the cylinder head-it seals the coolant passage from the combustion chamber and the rocker area of the engine, and the injector sits inside it. They don't have to be replaced when changing injectors, but should always be removed, cleaned, and resealed. The fuel into the oil will only come from a cracked injector body, leaking return lines, or leaking high-pressure lines. Could come from a seal leaking on the cp3, but that's not a likely source. I would suggest if you're going to get injectors for it, talk to Lincoln Diesel Specialty and get a master install kit for it-that comes with all the seals, gaskets, and O-rings for the injectors, return lines, and injector cups.

Balance rates only tell part of the story on injector health. The balance rates can still be good with bad injectors. A return rate test will tell much more than the balance rates.

As long as the high pressure lines are properly and thoroughly cleaned, they are probably fine. I've only ever had to replace one set due to rust and a couple odd ones here and there from them being bent or out of shape from someone working on it previously.
 
#7 ·
I was going to replace the high pressure lines definitely. I know Pensacola does not have the best reputation around but they had a really good deluxe kit that comes with everything plus new injectors (no core charge) and the whole thing, and it is pretty cheap so I might go with that, or an install kit from dmaxstore and injectors somewhere else because I would like to keep this below 3 grand and at Lincoln the injectors alone are exactly at 3 grand (I will not go reman, want these to last a long time). If you guys know where I should get this all without surpassing the budget or by a small bit that would be good. I just need to find out how the diesel is getting in.
 
#6 ·
I’m right there with you buddy. Got totally screwed buying an lb7 in January and after putting 2 grand into the truck I’ve got a total of 10 in it and still need to do injectors and adress the front pump seal leaking in the transmission. I should’ve just spent 14-15 on a good lly or even a high mileage lbz
 
#9 ·
FWIW, I bought the new Bosch remans from Lincoln Diesel. They are about $400 less than new new, but still have all the new features including updated bodies. I don't know what's reman about them as it seems literally everything is new parts. They also include the install kit and my truck runs good with no more hazing. A couple of the injectors I pulled out looked really bad, obviously leaking for some time or had other issues. The core charge is refunded, you throw them in the boxes and use a priority mail box at the post office.
 
#10 ·
Alright, so the guy that said he’d scan my truck has not gotten back to me with my request, and after letting the truck sufficiently warm up today visible haze was seen against the truck parked next to me as I backed up into a spot next to it, a nice light white smoke. Thinking at this point I should just bite the bullet and go new everything and maybe reman injectors, I was hoping @Brent@LDS would jump in and give me a few pointers before I go ahead and do all new cups and return lines, the whole shebang. Driving it like this and knowing I’m running bad/ clogged injector(s) and diesel-inhabited oil is bothering me, especially since this is the only vehicle I own, and I’m not going to drive my John Deere to work 🙂
 
#13 ·
No reason to even mess with the cups unless they come out during disassembly. As said, mine have been done 5 times - twice under warranty and 3 times by me. I've never even seen a cup out of a motor.

Also, lines are totally unnecessary if not damaged with corrosion or cracks. GM replaced a few of my lines on the first 2 injectors swaps but the rest of them are still factory.

When I do this job, I buy injectors and seals - that's it. So far, that's all I've ever needed except for the last time when I screwed up a return line.
 
#16 ·
The high pressure lines will corrode around the ends at the fittings. This usually happens in areas where they use salt on the roads in winter. If your truck sees / has seen that type use, it may be a good idea to plan on replacing them. They can also crack. As I said, some of mine are 17 years old and dong just fine - but I live in the south.
 
#21 · (Edited)
Oh, one other point. You don't need a scanner to check balance rates. I learned that right here on this forum. Your smart phone with Torque Pro on it and a bluetooth OBDII adapter will give you all that. It's what I use. Torque Pro was $4.95 to download on my phone and I think I paid about $50 for a high speed OBDI adapter from Amazon. You can get the OBD adapater for as low as ~$15 or so and you can even get them at Walmart I'm pretty sure. The great thing about it is that if you go that way, YOU now have a "scanner" that will even allow you to delete codes if you ever need to. I've also used my torque Pro on my son's car which keeps getting a miss-fire code. When the code comes up, it starts running like crap. Delete the codes and it runs fine again. Same on the wife's Camaro. Dead battery / battery change left a throttle position code. Used TP to delete the code and it ran good again and no CEL. I also used it to delete a intake air heater code on my truck that showed up a few years ago. I deleted the code, it came back so I did some research and ordered a relay for it. I deleted the code again while waiting for the relay to arrive.... the code has not come back after several years and the relay is still sitting on a shelf in my shop.

Also: check out this thread on SAC45s - https://www.duramaxforum.com/forum/.../990815-lds-45-sac-injectors-testimonial.html
 
#22 ·
S&S Diesel worked with Bosch to develop the SAC 00 which will be a drop-in replacement with no tuning required. They should be available any day now so send Brent an email at Lincoln and he will get you hooked up with everything you need.
 
  • Like
Reactions: long-time-dmax
#23 ·
I've been driving my oil making LB7 for months now.
2003 Sierra, 315000kms and needs 2 injectors and a head gasket.
I just keep an eye on the level and when it starts to smell strong, oil/filter change.
Prob not the best way lol. Dragged a magnet through the oil with a strong LED flashlight and there were no filings to be found.

Only has to last one more day......I'm tackling my LLY head swap this weekend.

I didn't want to spend $4g + cdn on parts to fix it every time, so I'm rectifying the situation with heads that have "easier to replace" injectors.

Although with a 2002 its more difficult to do the swap. But is possible.

Sent from my LG-H831 using Tapatalk
 
#24 ·
Well I got the truck scanned today, did a cylinder test and cylinders 1,2,3 were all sitting at 600-605 while the rest were at 611-615 so those 3 in the low possess bad injectors. The guy I had scan it said he goes with Injectors Direct since they ship so fast and he has done multiple injector replacements on the lb7. Still like how Lincoln sounds but unless I get swayed by Brent or someone else it looks like Injectors Direct will be who I’m with.
 
#26 ·
Brent @ Lincoln has always been quick with with me and others I know who have used him. He is also a dealer for S&S Diesel and I highly recommend the SAC 00 injectors as they are the best replacements for the LB7 that will probably outlast the truck. This is the type of job you only want to do once and not twice then end up spending 2x-3x the $$$ in the long run.
 
#25 ·
I too have been looking at Injectors Direct. I will be doing the job real soon on mine. One of my big questions was should I buy a kit that includes new cups, hard lines, and glow plugs. I think what I am going to do is pull the injectors and see how the lines look and if any of the cups come out. If the lines are not corroded I will not buy those and if none of the cups come out I guess there is no need to buy those either, correct? If any do come out, should they be replaced or can they be cleaned up and reinstalled? Should glow plugs really be replaced while in there?
 
#27 ·
after looking at Injectors Direct and how even new injectors and everything else has a core charge (could just be reading everything wrong) I will probably go with Lincoln. Just need to get a kit sorted out perfect for me. I am personally going to get 4 injector cups since I have diesel in the oil and want to keep everything good, but I don’t think they are necessary. The hardlines that feed the injectors are a MUST for replacement, they corrode too easily and it’s not worth it to clean them and reuse them. I personally don’t need my glow plugs done but I’m sure you can do it if you want to. I am using Lucas additive in my truck and I’ll see how it does on a few more tankfuls, see if the problem sorts itself out, but if not I’ll do the job
 
#31 ·
Like I said earlier in the thread. I've done it 3 times now. I usually start on a Friday night after all my stuff has arrived. I'll start pulling one side down and work till I feel like quitting. Then on Saturday I'll usually have it torn down and start going back together with it and then finish it on Sunday.

It's not a hard job but it's a big job and it just takes some time. I don't push myself, just work till I get tired.

The one thing I did on the second replacement that really has saved time and effort since then was replace all the valve cover allen head bolts with normal, hex head bolts. There's about 24-26 of those allen head bolts you have to take out. Many of the bolt heads get filled with gunk and you have to dig that crud out to get an allen wrench / socket in there. Then there's the bolts back by the firewall - especially on the driver side. Some of them are really tough to get to and the extra length of an allen socket makes it even harder. Replacing the bolts allows me to use a 1/4" drive wiggler socket on a 12" long 1/4" drive extension on all the valve cover bolts and it REALLY saves time and aggravation.

And just my personal opinion but if the SAC00 type had been available before, there's no way I'd have ever not used them. Heck, I'd have used SAC45s last time if I'd have know about them- I think they were just coming out last time around for me. There's no way I'd have spent the money on the OEMs knowing I'd be right back in there replacing them a few years later when I could have spent a little more on SACs and done it one time.
 
#33 ·
There is a tool but I've never used one. Most times just a twist and a tug and it comes out. Last time I had one that was hard to get out and I just kept twisting and tugging by hand. That injector had apparently been leaking / dribbling because the reason it was stuck was that there was a LOT of carbon build-up on the tip and that's what was making it hang up. By twisting and tugging I was knocking the carbon off and eventually, enough came off to let the injector come out. I think if you get one stuck like that and you use the extractor tool, that's when cups start coming out.

Knowing now that it was carbon holding it in, if I ran into another like that I might do something like poor some Sea Foam into the cup and let it soften up that carbon a bit.
 
#34 ·
I heard that a crowbar under the keeper on them works well, I’m assuming mine aren’t all that bad since their cylinder rates were not horrendous. I might as well have the cups come out to replace their o rings since I’m paranoid about leakage now. Hopefully that and the SAC 00s will seal everything nicely
 
#35 ·
They should come out by hand easily. I've only ever had a problem with that one.

The reason I had the problem was that that injector was bad from day one. I got that set of injectors from a GM dealer that I had also got the previous set from. The first set was fine and lasted the normal 80k miles in my truck. The second set apparently had one bad injector from the get-go. Once I had put that set in, I was still getting a bit of black smoke at idle and my mpg never came back as much as usual. Usually, when my injectors go out, I lose about 2 mpg. When I replace the injectors I get that 2 mpg back. That time, I was still down about 1.5 mpg after installing the new injectors and I was still getting black smoke at idle like I said. I wasn't going to tear it all back down for a little black smoke so I just let it go. 80k miles later I started getting the haze at idle and some diesel in my crank case as is pretty much normal for my truck. When tearing down, I ran across the "stuck" injector (#6) and once I got it out discovered that the tip was covered in carbon and put 2 and 2 together - this is why I was getting black smoke at idle all that time. So yeah, normally, if you don't let your injectors leak forever you shouldn't have any problems and the injectors should pretty much come right out. The injector tips just poke thru the hole at the bottom of the cup and there's a compressible copper washer that seals the injector body to the bottom of the cup so it's not really a tight fit at all. It's just when there's a bunch of carbon built up on the tip inside the combustion chamber that you run into a problem because you have to get the tip back up thru that hole in the bottom of the cup. If there's carbon caked all over the tip, it won't come back thru the hole in the bottom of the cup.

Like I said, something like a little Sea Foam and 20-30 minutes of soaking would probably make any stuck ones easy to get out. I just didn't realize why that one was stuck until I got it out and could look at it. A little carbon on the tips is normal but this one was caked in it and I'm sure that it was a lot worse before I knocked most of it off by twisting and tugging.

I'll re-emphasize the valve cover bolt thing too. That little trick probably saves me close to 2 hours or more on tear-down and probably 1+ hours on re-assembly. It made HUGE difference in frustration factor. The allen head bolts are nicer looking but they really are a REAL PITA.

I got the set in there now from LDS and very happy with quality and service.
 
#36 ·
A couple years ago a friend and I made our own special tool for removing the injectors. It just so happens that the threads for the high pressure line are the same as the lug nuts for our trucks. I had a few spares rolling around, so we welded a short piece of pipe to the top of the lug nut. Took another piece of pipe, bigger than the first, with a washer welded to the top of it. Then welded another washer to the top of the first pipe. Makes a nice little mini slide hammer. Even on the stubborn, stuck in injectors, a couple good smacks with it and they pop right out. I use it all the time.

I think I've said it previously in here, but I pull the injector cups on every job I do just to ensure I don't have or create a problem there. Its not much to be sure you don't have an issue
 
#39 ·
I can't say whether the dealer pulled and re-installed my cups the 2 times they did injectors but I did my first set at 210,000 miles and 2 more sets since then. So 190,000 miles ago I did not pull the cups. Nor did I pull them 110,000 miles ago. Nor did I pull them 35,000 miles ago. Never had a problem.
 
#42 ·
Soooooo I'm in the same boat, bought a 2002 and every once in a while get a very light haze. #5 injector is the worst at 3.8, all the others are within 2.5. Hoping I can wait till the end of summer early fall as within a couple weeks junior number 2 should be here. Gonna be super busy, just hoping to see what everyone else is using and having luck with, considering injectors direct. Called and talked to the owner today and he was very helpful on my questions and didnt hurry me off the phone like another company I called. One more question. How do you know exactly if diesel is in the oil?
 
#43 ·
I am siding more with Lincoln since I didn’t like how even the return lines had core charges. If you want to test if diesel is in the oil do what I did- get the oil warm and find a piece of printer paper or mail envelope, some thing like that and take the dipstick and let it drip into the paper, over the course of a minute or so a defined dark mark will be in the center of a lighter brown circle slowly creeping away from the dark mark. This is diesel fuel in the lighter mark as oil and diesel don’t mix so they are trying to separate. If you do not see this then you do not have diesel in the oil. If so I recommend doing what I did and changing the oil pretty soon and running a CAT oil filter kit from MDDP, just a pretty good piece of mind with these trucks
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top