Hazing LB7 - Couple of Injector Questions

[sneaky98gt]

Happy Thanksgiving everyone!

As the title says, got a 2003 LB7 that's hazing quite a bit at idle (though I'd stop short of saying it's "smoking"). Started maybe 10k miles ago when I noticed the exhaust smelling pretty strong. Then around 5k miles ago I started noticing it visibly at nighttime if lights caught it just right. And now recently, I can sometimes even see it during the daytime.

Truck has just under 240k miles on it. I bought the truck at 200k from a dealership, and that dealership had actually replaced the injectors at 180k with Bosch remans (and provided the paperwork). I'm a little disappointed in the idea of the injectors starting to haze at not-even 60k miles yet, but after doing a bit of reading, it seems that that's not completely unheard of.

Other than the hazing, the truck runs perfectly. Got 19.7 mpg hand-calculated on the last tank, cranks fine hot and cold, no loping, no knocking, etc. It is not making any oil, and the oil has no diesel smell or look to it (paper towel test). I've had a Kennedy lift pump on it since shortly after buying it, with a Baldwin BF1212 aux filter and a BF9882 filter up front. It has a built trans DSP5 tune, was on the 3rd tune (I think 125 hp) for the numbers below.

Balance rates:
Cyl. 1: 1.43
Cyl. 2: -4.32
Cyl. 3: -0.21
Cyl. 4: 0.18
Cyl. 5: 1.96
Cyl. 6: -1.09
Cyl. 7: 0.78
Cyl. 8: 1.92

Fuel pressure: 34.8 mPa
Main injection: 6.2 mm3

Going by Fermantor's method of correcting the balance rates (assuming I'm doing it correctly), those would be:
Cyl. 1: -0.37
Cyl. 2: -6.12
Cyl. 3: -1.98
Cyl. 4: -1.62
Cyl. 5: 0.16
Cyl. 6: -2.89
Cyl. 7: -1.02
Cyl. 8: 0.12

So both the "normal" and "corrected" numbers show the #2 injector as being bad, but the other 7 as actually being fairly good. The main injection rate is also not crazy far off either.

Here's my questions:

1. Is there anything else reasonably easy to test before diagnosing the injectors as bad? Definitely don't want to spend the time and money replacing injectors to find out it was something else causing the hazing.

2. I know I'm going to get slammed on this one, but would it be completely crazy to only replace the one injector? This assuming that I can find someone with a Tech 2 to shut off the #2 injector, and assuming that shutting it off clears up the hazing.

I completely understand that the general consensus is to replace all the injectors, and eventually, that's what I'm going to do (with SAC45s). But, I do all my own work, so my labor is "free" (yeah, I know: not really). On top of that, I know that the other 7 injectors are Bosch's with <60k miles on them, and the balance rates above (and main rate) suggest that they're still in pretty good shape. If the #2 actually is the one causing the hazing, then replacing just that one for a few hundred bucks and a day of my time doesn't sound completely crazy to me. Even if it only buys me 30k more miles (putting the complete set into more "normal" lifetime territory), that's at least a couple more years at the rate I drive it.

Thoughts?

 

[darkness]

At a minimum I would change the 4 on that side. You're already in there. But at the end of the day you still have VCO's. Do the SAC45's and be done. JMO...

 

[sneaky98gt]

Alright, figured out how to shut off the injectors through the DVT in EFI Live. It is DEFINITELY the #2 injector that's producing the vast majority of the smoke. I'd say shutting it off cut out 80%+ of the smoke. It went from a very noticeable cloud all around the truck clearly visible in the streetlights overhead (and billowing from the exhaust with my flashlight as a backlight), to not noticeable at all in the ambient streetlights and only barely noticeable with the flashlight-as-a-backlight at the tailpipe. The smoke still visible with #2 shut off could be normal old-diesel-motor smoke, not sure, but it was light-years better and the smell around the truck not nearly as bad.

Shutting off each of the other 7 injectors made no difference in the visible smoke.

At a minimum I would change the 4 on that side. You're already in there. But at the end of the day you still have VCO's. Do the SAC45's and be done. JMO...

Yeah, I almost certainly knew that would be the recommendation, and I'm sure it's a good recommendation. A part of me, though, is still tempted to take the chance at just replacing the one. When I started typing this thread this afternoon, I was only planning to ask if there was anything else to check before replacing all of the injectors. It wasn't until I actually wrote everything down that I realized that all of the numbers suggested a single injector being bad. I've seen a handful of old threads where someone isolated and replaced a single injector, and got lots more miles out of the set. I do think the key word there is "isolated".

I'm not trying to be cheap; I've got plenty of money to replace all of them (was budgeted for when I bought the truck). And when I replace all of them, it will definitely be with the SAC45s. But with the main injection rate not being nearly as bad as I usually see with bad injectors (in old threads around here), I'm looking at it more from the point of prolonging the life of the 7 (seemingly) good injectors rather than being cheap. They appear to have a lot of life left in them. If a $220 injector + a few bucks in misc. gaskets gets me another 20k-30k miles before having to spend $4k+ on the full set, then that's definitely a pretty strong $ per mile ratio.

Or, I could replace the one, and have another one go south 2k later. In which case, FML. LoL. I'm still undecided.

 

[2004LB7]

Be careful with using the DVT controls to determine which one is the culprit. I had used it and it's injector numbers didn't corelate with the actual injector numbers. I suspect it's actually the firing order. I know some others reported similar issues with the missmatch while others did not. Makes it difficult to nail down the right injector. Apparently the Tec2 doesn't have this issue

Have you tried cleaning the injectors yet?

 

[sneaky98gt]

Be careful with using the DVT controls to determine which one is the culprit. I had used it and it's injector numbers didn't corelate with the actual injector numbers. I suspect it's actually the firing order. I know some others reported similar issues with the missmatch while others did not. Makes it difficult to nail down the right injector. Apparently the Tec2 doesn't have this issue

Have you tried cleaning the injectors yet?

Have you had an LB7 in which the DVT numbers didn't match up?

I read through a bunch of old threads regarding that issue when I was looking for info on how to use the DVT function. There was a LOT of he-said-she-said without much definitive proof either way, but the conclusion I came to was that the LB7s were fine, and that it was only the LLYs that had issues (if there indeed were any).

Regardless, I pulled my balance rates with my Aeroforce Interceptor gauge (and that's what I posted above), and it showed #2 as being out. Shutting off #2 in the EFI Live DVT also cut the smoke out. So with 2 separate scanning methods / softwares showing #2 as the culprit, I feel relatively confident in it.

I have not tried cleaning them. Again, did a bunch of reading over the weekend, and came to the conclusion that a cleaner isn't going to fix a worn injector. That, and the fact that the GM cleaner is now $100+. I might would give it a try at $20, but heck, $100 is absurd.

 

[Bdsankey]

At a minimum I would change the 4 on that side. You're already in there. But at the end of the day you still have VCO's. Do the SAC45's and be done. JMO...

^ IMO if you've got one injector going it's very likely there are some not far behind it. You can try doing an injector cleaning but the GM cleaner is extremely expensive and at the end of the day it's a bandaid. I've never had the cleaning actually do anything but buy a customer 2-8 weeks (my personal experience, other members have had great luck with doing the cleaning method).


I would recommend if you're going to keep it going to a set of SAC nozzles from a reputable company and being done with it forever. That said, the newer VCO remans have major improvements over older remans.

 

[ZeroGravity58]

Save yourself the headache. I did this with my old 01 when I didn't have the money to buy a whole set. I replaced one at a time and it seemed like every month I was pulling a valve cover putting in another injector. After replacing 3 I just replaced them all. All the return seals and all add up over time also.

 

[2004LB7]

Have you had an LB7 in which the DVT numbers didn't match up?

I read through a bunch of old threads regarding that issue when I was looking for info on how to use the DVT function. There was a LOT of he-said-she-said without much definitive proof either way, but the conclusion I came to was that the LB7s were fine, and that it was only the LLYs that had issues (if there indeed were any).

Regardless, I pulled my balance rates with my Aeroforce Interceptor gauge (and that's what I posted above), and it showed #2 as being out. Shutting off #2 in the EFI Live DVT also cut the smoke out. So with 2 separate scanning methods / softwares showing #2 as the culprit, I feel relatively confident in it.

I have not tried cleaning them. Again, did a bunch of reading over the weekend, and came to the conclusion that a cleaner isn't going to fix a worn injector. That, and the fact that the GM cleaner is now $100+. I might would give it a try at $20, but heck, $100 is absurd.

Yeah, several times with my LB7 I had trouble finding the bad injector using the DVT controls. I too saw that all the information and threads pertaining to it where for the newer models.

 

[DuramaxRamRod]

I did all 8 on my dad's '03 at ~140k and then one went with a second one questionable both on the passenger side bank ~20k later. So I change that whole bank and it's been fine since. Even with having a FASS 95 on before changing the injectors with a CAT UHE Filter in the stock location running optilube every tank the VCOs still fail.

 

[sneaky98gt]

That said, the newer VCO remans have major improvements over older remans.

See, that's what's tempting me. They're GM-installed Bosch remans from 2017. I see stories of people only getting 60k-80k before having issues, but I also see stories of trucks getting 125k-150k+ miles out of a set. It seems to me that all, or most, or several, of a 3-year-old set of injectors with barely 50k miles on them should not be on their way out. Assuming that GM / Bosch designed them for more than a 75k life (based on their 200k extended warranty back in the day, and that these newer models are "improved", I'm betting they are), I'd think the more likely scenario is that I had one fail early, rather than this just being the first of a worn out set to fail. It makes me wonder how many of those low-mileage replacements were actually just a single injector that failed early, with the rest of the set still having lots of life left.

I think this is a completely different conversation if I've got 100k+ miles on them, or if some of the other balance rates are out or marginal, or if the main injection rate is less than 5 mm3. But none of those are the case here, which is what's tempting me. It seems like the other 7 aren't just "fine", they actually look pretty good, or at least as good as I can say without doing a return rate test.

I don't know, definitely on the fence about it. As I get older (well, if you call 30 old, lol), I value my time a lot more than I did when I was 20. So there's definitely a lot of value in the peace of mind of doing the whole set once and not having to worry about it again. But, we're talking $300 vs. $3000, and the potential of that $300 lasting me several more years. That's what's making it a hard decision.

Regardless, I'm not going to replace a whole bank. It's either going to be just the one with a reman, or the whole set with SAC45s from LDS. So either really cheap, or really expensive. LoL.

Yeah, several times with my LB7 I had trouble finding the bad injector using the DVT controls. I too saw that all the information and threads pertaining to it where for the newer models.

Well in that case, I may spend some more time definitively diagnosing the correct cylinder (assuming I decide to replace the one).

I did all 8 on my dad's '03 at ~140k and then one went with a second one questionable both on the passenger side bank ~20k later. So I change that whole bank and it's been fine since. Even with having a FASS 95 on before changing the injectors with a CAT UHE Filter in the stock location running optilube every tank the VCOs still fail.

And that's kinda the line I'm trying to walk here. At 20k in your case, that's clearly a premature failure of a single (or two) injectors, not the whole set wearing out. The question is how, or whether, to make that call at 50k-60k miles. Like I said earlier (and you just provided even more proof), there's clearly precedent of sets lasting way past 100k. I've got exactly 0 data to back this up, but it would seem that entire sets failing at 50k-60k would be the exception, not the norm, even if it is common for a single injector to fail prematurely.

 

[zakkb787]

If you replace one injector, you’ll be back in there shortly with others failed from cracking the lines loose and dropping sh!t into the injectors. If you’re fine with eventually replacing them, nothing wrong with doing VCOs. That’s the route I went with my lb7. At 60k you’re borderline on service life of VCOs. Some guys have no issues like you said others do. As big of a pain as it is to get in there the smart thing is do a whole set. Believe me, it sucks pulling valve covers twice within a few months.

 

[fl0w3n]

If you replace one injector, you’ll be back in there shortly with others failed from cracking the lines loose and dropping sh!t into the injectors. If you’re fine with eventually replacing them, nothing wrong with doing VCOs. That’s the route I went with my lb7. At 60k you’re borderline on service life of VCOs. Some guys have no issues like you said others do. As big of a pain as it is to get in there the smart thing is do a whole set. Believe me, it sucks pulling valve covers twice within a few months.

I was about to say the same thing, you’re going to have to crack all 4 high pressure lines and if they weren’t sealed up there’s a good chance you just clog up the remaining 3 injectors.

there’s a possibility the dealership just tried to clean the high pressure lines instead of replacing them, and just one of them dropped some crud and clogged you up.

if you only do one, at the minimum I’d still replace all 4 lines and seal them... but I still think it’s a big risk. My 2nd time doing SACs and a high pressure line leaked after a month and just replacing that was a huge bummer. I can’t imagine getting back in to do an injector after a month.

 

[fl0w3n]

Where are you located? Have you tried calling the dealer to search for the cleaner?

I was able to buy the last few bottles in Northern California or even the state maybe and they shipped it to me. It didn’t really wind up helping much though.

 

[sneaky98gt]

Quick update. Short version: 4k miles on replacing just a single injector and all is well so far.

Longer version:

I ran injector cleaner through them first. Results were super promising, as the smoke disappeared and balance rates came to almost perfect during the cleaning procedure. However, after only a few mile drive, all 8 were back within 0.1-0.2 of what they started at. Bummer.

I decided to do the dumb thing and only replace the one injector. At $250 and a casual weekend's worth of my time (a.k.a. beer drinking time), it was too tempting to try versus $3k-$4k.

The high pressure lines were severely rusted. However, I decided to roll the dice on them as well. EvapoRust and an ultrasonic cleaner had them looking (nearly) brand new.

I understand now what everyone talks about with regards to crap falling down into the injector inlet. There's really no way to avoid it. I did, however, disassemble the bad injector (to see how everything works), and from that I was able to figure out a good way to clean the remaining three. I took some pictures detailing it which I intend to post up at some point. I also disassembled the nozzles and ultrasonic cleaned them.

All in all, the job was pretty easy really. I did pull and reseal all 4 cups. I think the worst part was scraping the old RTV off the valve cover. I swear that took two hours by itself.

I've got about 4,000 miles on it since replacing the injector, and all is well so far. For unknown reasons, the #8 injector went from roughly +2 before to now -2.8, though it has held steady at that number. The other 7 are all +/- 1.5. Main rate went up a bit to 6.5 mm3. Haze is 90% gone, can really only see it if you're really searching for it in the dark with a flashlight. Can still smell it somewhat (like if you're standing near the back of the truck), but nothing like before (could smell it in the cab sitting at a stoplight for 15 seconds).

I'm keeping my fingers crossed, but so far things are looking good. If I can get 10k-20k miles out of the set, that'll allow me time to learn how to tune the truck myself (for when SAC45s go in) and hopefully I'll have more space and more time to work on it by then as well.