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LB7 new injectors but bellows white smoke during warm up

weldguy

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SO I have been reading the various duramax forums for several months now as that is how long I have been dealing with my issue. I did land on this forum to post though :)
Truck: 2003 GMC 2500HD with muffler delete and banks 6-gun 132xxx miles, GM injectors at 70K, replace #3 and #7 at 120K
Long story:
Last March, I was driving my truck hard and as I slowed down for the corner, it started running rough. Then missing, and blowing black smoke. Plug in with my Foxwell scan tool and it reads all zeros for balance, and 1mm3 or less for fuel rate. Was able to figure out that means injectors are stuck open and the ECM threw its hand in the air. Bought some Standard Motor Product reman injectors because the had a 3 year warranty (insert Tommy Boy warranty skit). Fast forward a couple months before I could find someone to work on it since the reputable diesel shop in Michigan is several hours away, and I now have no tow vehicle. I found that the local injection shop guy does swaps on the side - perfect. He did the swap and one injector is junk out of the box. He replaced that one with one of his Bosch remans. He put it back together and it had a fuel knock - no biggie he said, leaky injector.

Drive it, and research is telling me injector knock is very bad. But, it also BELLOWS white smoke, spits and sputters from about 165 ECT to 175 ECT, via the dash gauge. I have not been able to scanning while it is doing this, so i do not have good details.

I have trended fuel pressure, and it generally follows, but is probably more than the 150 psi that I believe is called out for replacement. Balance rates are: Cyl 1: -1.9 to -2.1, Cyl 2: .5, cyl 3: -3.1 to -3.5, cyl 4: .7 to .9, cyl 5: 2.2 to 2.3, cyl 6: -.5 to -.7, cyl 7: 1.0 to 1.8, cyl 8: .6 to 1.0. These are at idle, in park, 8mm3 delivery, but may not have been over 185F ECT. MAF reads within spec at idle.

I have before and after pics and videos of scan data if anyone is interested, minus blowing white smoke.

I have been directed to check the turbo, high and low pressure ducting, verify functionality of the boost pressure sensor, and check the MAF sensor. I have bought and hope to use some BMW injector cleaner that was more or less verified to be the same and the old GM/Techron cleaner on a different forum.

I am going to stop driving because of the knock, but I hope to do better diagnostics and a cleaning this weekend.... if my toddler lets me.

I am sure the shortest of the short answers is junk injectors, but I am worried that transition white smoke could be a deeper problem.

Does anyone have any thoughts?

Thank you
 

MrMarty51

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Welcome to the forum Weldguy.
I dont know how much it matters with the LB7, but, whenever the 6.5 is having problems, everyone tells the owner, clean those grounds and battery cables.
Get those terminals to bright and shiny and same with the contact surfaces of the studs, bolts and batteries.
 

THEFERMANATOR

FRANKENBURBAN
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Use ONLY Bosch injectors. If the problem started with your injectors, then it is most likely your injectors. Balance rates are a diagnostic tool, but not the end all be all of diagnostics. I like to ramp up the rail pressure and see if they stay steady. Weak injectors will go all over the place when you raise rail pressure.
 

weldguy

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Thank you all for your replies

Ok, she has electrical demons that I do know of, so I will run down the the grounds

The more I read, the more I question why these non-Bosch injector are still available. Do people get lucky and have them run good, or does everyone just live with a little knock and haze after they spent $3500 instead of $4000...

Bosch only, lesson learned. What about the S&S SAC00 injectors? According to their site, they worked with Bosch to develop the nozzle, but I do not see where they advertise that they are Bosch certified.

I do have to give props to the online autoparts dealer that starts with an R and ends with auto. I sent them an email complaining about my situation and the idea of warrantying out what I have only to install more junk. They replied with their warranty policy includes full refund. SO, it sounds like I can get a full refund, which would include my original core charges that, due to other things, I had to eat. That would almost cover the whole job with Bosch remans, or cover the injector cost with the SAC00's
 

WarWagon

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What about the S&S SAC00 injectors?
They appear to know their stuff offering a CP3 conversion for the '19-20 RAM Cummins CP4 disasters.

Stop running the engine with bad or suspect injectors. Quit "playing with it" for diags as well: again stop running it before damage gets worse. A stuck open injector can melt a piston before you can turn the key off, so, it may not matter sometimes. With the possibility it wouldn't hurt to do a compression test just in case "Warranty on bad injectors" owes you an engine not just a refund. A Borescope inspection may be a good idea as well looking for melting damage on pistons.

Check your fuel: Does it smell like gasoline? Drain the filter into a glass jar: Does it have water in it?

Look on CL for inexpensive towing options. U-Haul and rent a truck and car trailer.... Get it to the shop that can diagnose it and warranty the labor on the repair.

Injectors are expensive, second only to an engine rebuild and sometimes the rebuild needs injectors*, so everyone "wants a deal on the cheapest they can get their hands on." Sadly Garbage Injectors can take the engine out and vendors are happy to sell em.

* Engine and a new set of injectors can be a total loss expense being as much or more than the truck is worth.

So with the risk of ruining the engine and your depending on other's labor I would suggest you find a way to get it to the shop and have "A" shop handle the repair and warranty the repair(s) needed. The shop may even have a deal with a tow Co to pickup vehicles: ask.
 

MrMarty51

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It os okay to mention Rock Auto in this forum. They are, I believe, the owners of this forum and a main sponsor.
I could be wrong on the owner part but it seems I have seen that somewhere. 🤷‍♂️😹
 

weldguy

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Good to know about Rockauto.
I am a long time forum lurker, first time joiner/poster in any forum. Trying to find my bearings

WarWagon - Thank you for telling me what you really think. People at work say that I do that as well. Diabetic friendly for sure🤣
Part of my concern over this white smoke issue is I did exactly what you are saying not to do after the 3 injectors stuck open in march - I never drove it, but it ran while I was trying to make sense of it.
I have sampled the fuel recently and it looks and smells fine; and the test swab thingy said there was no water.

I would love to do a compression test and stick my bore scope in there. But the guy who did my injectors the first time says that with vintage of truck (thank you road salt), I would have have to pull the heads to get the glow plugs out; why he won't change glow plugs anymore. He told me even made a vibrating wrench to try and get them to accept penetrating oil. That and cash work and discount injectors from Rockauto I don't imagine would help with a rebuilt cost.

I am getting the feeling that there is a lot of dice rolling in working on these things when money is tight. I could check compression and find out it is fine and the injectors are the only issue, I could find I need a complete rebuild, or I could break off a glow plug and be a half tear down and injectors. A total loss expense verses truck worth - agreed. Current replacement cost has shown me a LBZ with 328k miles for $17k and the only older vintage trucks listed as part-outs.

So, your points are all taken, including figuring out how to get it to THE place, but I think I am going to roll the dice and not mess with it anymore, send it to my new mechanics of choice (2 GM trained guys who hung out a liscened shingle and have already done a lot of work elsewhere in my fleet) and have them do their best, and pray it's like THEFERM said. I just have to decide if I go Bosch or SAC00 since I have seen where THEFERM said they are the greatest thing since sliced bread back in 2019.

I understand why there are so many 6.5's here. Different place, different time, different source of income and I think I would have a 6v53T in my 85 one ton chevy... I like me loud and obnoxious trucks.

Thank you all for your input
 

THEFERMANATOR

FRANKENBURBAN
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There is nothing wrong with SAC injectors, IMHO they are the ONLY way to go if you can afford them. I put SAC 45 overs in mine before the SAC00 were out(would have went with them instead had they been available). Some people get lucky with the cheaper injectors, but others get pissed off and unload the truck because of them, or they break a crankshaft and scrap the truck because they're tired of pouring money into them. Even GM stopped selling Bosch injectors and cheaped out with an aftermarket injector trying to save money. LB7 injectors are one area where I will ONLY buy Bosch from a Bosch dealer(nothing against site vendors, but my engine is to important to me to take chances). I know I learned my lesson early on when I bought a set of injectors from pensacola diesel, I ended up having to go and buy a set from GM plus core charge(back when GM sold Bosch) since I had sent my cores back to pensacola so I could prove to them it was there injectors making my truck run like crap, then I had to threaten to take them to court to get a set of cores back from them to give to GM to get back my $1200 in core charges.
 
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