Low RPM Power & Black Smoke, no codes

[rockien]

Long story as short as I can make it. Thanks in advance for your help.
This 2007 LBZ is my nephews truck that has about 250,000mi & has been sitting for months now. I have EFI Live to datalog it and I told him I would scan it and see anything that doesn't look right. I have only programmed gas engines with EFI, so no diesel experience. The truck ran perfect for 12 years with EGR delete, AirDog FP/filter, EFI Live DSP5 with IdahoRob tune. There was a problem with antifreeze, or something and the shop he took it to said it needed head gaskets. They replaced gaskets, installed rebuilt heads-ARP bolts and that's when all the problems started. The shop worked on it and said he needed Fuel injectors. He had the shop replace them with Bosch injectors from Injectors Direct. Not knowing how it ran after the head gasket changed, this is how it sits now. The bad thing is his wife got involved and yelled at the shop (very badly) and they told them to take the truck and they will not work on it any further.

It starts fine, but not smooth (like chugging). It runs like that when accelerating up to about 2400rpm and blows black smoke. Over 2500rpm it clears up and runs with lots of power. Cruising it blows black smoke every time you give it pedal to go up a hill or increases speed.
We pressure tested the intake tube from turbo for leaks and found none. It holds 20 psi and leaks down in about 1-1 1/2 minute, guessing through the rings, intake-exhaust, and overlapped valves. We cleaned the MAF with CRC Cleaner. I data logged the truck and commanded&actual fuel is the same along the complete log. Baro and MAP track fine with MAP a little less psi. Turbo desired & vane position track very close. Fuel pressure desired&actual are the same. Injector balance and Calculated Fuel Rate, don't seem to be out of tolerance. I have access to the truck and can datalog any additional PIDs.
At idle Baro-12.9, MAP=10.9-31.3, MAF= ,FRP=30Mpa idle- 4300-26,400PSI, Boost 12.9 linear up to 36.9PSI
I have the scans to share for pros to give any advice.
The good thing is, my brother has a 2007 LBZ for us to compare datalogs and maybe swap sensors to test with.

 

[2004LB7]

I'm going to guess injectors direct is your issue

 

[rockien]

really, Injectors Direct are not good replacements? So he spent 5k to have bad injectors installed? Wouldn't the balance rates show something way off? I can disable each injector and the motor stumbles, indicating they are at least firing. The original injectors were working fine until the shop installed rebuilt heads and gaskets. Can anyone tell me how I can Identify or measure for a bad injector?
I would think some PIDs should be able to help diagnose this type of issue. I am not inclined to spend another 5k to replace all the injectors just to find out it still runs like crap. Anyhow, we'll keep looking

 

[08lmm72mm]

What are the balance rates? What about fuel mm3 at idle? I'm leaning towards injectors direct aswell

 

[TheBac]

X3. Injectors. As said above, post balance rates and mm3 at idle.

Why do people keep buying those crap injectors from that company?

 

[rockien]

The EFI Live scan of these are attached in the first post, but here are the numbers. Guessing you guys have had or heard of a lot of issue with that companies injectors. Fuel pressure is 4351psi at idle
calculated fuel rate is 7.8mm3
1= .39
2= -2.14
3= -2.31
4= 3.35
5= -2.20
6= 0.36
7= -2.34
8= 3.77

 

[rockien]

X3. Injectors. As said above, post balance rates and mm3 at idle.

Why do people keep buying those crap injectors from that company?

Probably because they don't know about the bad junk they sell, I wouldn't have known until I started searching around.

 

[2004LB7]

main rate looks a tad low which can be from leaking injectors. is that in gear or neutral?

 

[rockien]

Those number are idling in neutral. I have the truck here and am going to take a couple of other datalogs. Anything in particular to scan that might help identify a leaky injector. Or should we start looking for a complete set of injectors? what brand or where to get good ones.

 

[Dozerboy]

Make sure it's up to operating temp to check balance rates.

 

[rockien]

Make sure it's up to operating temp to check balance rates.

Thanks, all of our scans have been up to operating temp.

 

[rockien]

Ran some drive tests and scans. changed the MAF and it fixes the chug and some of the black smoke. However an injector stuck open a few different times, it knocked and blew white smoke big time during that 5-10 seconds. I guess you are right about these injectors. I used EFI to increase the fuel pressure to 13,000PSI at idle and it started knocking. Then I disabled each injector to see if the knock went away. It quit knocking when I disabled #1. Not sure if that is a valid test or not, but seems like that injector has a problem. comments?

 

[2004LB7]

that method sometimes helps locate bad injectors but it they are leaking then turning them off doesn't normally stop the leak. but based on what you've found I'd say it's even more likely to be injectors.

why did you have the injectors replaced if they were running good? seems like an expensive mistake

 

[TheBac]

Probably because they don't know about the bad junk they sell, I wouldn't have known until I started searching around.

Oh, they know alright. Far too many people have had bad experiences with them that theres no way they dont know. Sorry.

 

[rockien]

that method sometimes helps locate bad injectors but it they are leaking then turning them off doesn't normally stop the leak. but based on what you've found I'd say it's even more likely to be injectors.

why did you have the injectors replaced if they were running good? seems like an expensive mistake

The truck ran great before they changed the heads and gaskets. Then it ran like it does now and the shop said the injectors were bad and they needed to be replaced. It's looking like the new injectors are not any better, or maybe worse than the original injectors. man I hate when people get taken because it seems like so many mechanics these days just replace parts until it runs right. I was not involved when this all took place, but I would have not been inclined to replace the stock injectors since it ran perfect before the heads. What really good brand of injectors do you guys recommend using for this engine?

 

[2004LB7]

Dynomite Diesel (DDP), Exergy, or S&S or the dealership are all viable options

contact Bdsankey here. he's a supporting vendor and can hook you up with injectors

 

[rockien]

Thanks for the help Jason. I'll pass along the info, but it might be awhile before my nephew has the money to put into new injectors. Maybe Santa will bring some for Christmas.

 

[Dozerboy]

The problem with LBZ injectors is sometimes they're bad, but it doesn't really present itself as an issue. Oftentimes they start returning too much fuel which isn't a big deal until you hook up to a trailer or you start driving the truck hard in hot weather. My truck made over 500 horsepower on the stock injectors and never missed a beat. 17 years later and 200,000 miles I replaced them mostly to upgrade to 100overs. After I did that it was obvious those injectors were returning a ton of fuel. My fuel system keeps up with my 100overs better than it kept up with my stock injectors becsues they were returning so much fuel.

Good luck!

 

[KyleC4]

That shop they took it to was bad from the get go. I’m yet to find a need to replace a cylinder head, let alone two, when it’s been diagnosed as a head gasket issue on one of those trucks. And if that’s the company the shop used for injectors I can’t imagine who they used for cylinder heads.

 

[08lmm72mm]

Those balance rates and idle mm3 are terrible. Expensive lesson learned. When it comes to injectors always buy from a reputable source either the stealership or a supporting vendor.