[structures]

Just when you thought nobody would ever ask another injector question. I just picked up a 2001 K3500 Crew Cab Dooley with 226,000 miles. It's a fixer upper. Nobody wanted it because it smokes bad and also has the transfer case pump rub leak.

Drives great, seems to have good power, and starts right up no problem. No active codes (my cheap code reader showed some historical codes on the ABS). Crankcase oil full. Small black oil leak underneath up at the front, couldn't see any obvious leaks, power steering hose looked wet with oil. I just crawled underneath for a few minutes. The smoke is pretty thick at idle and kind of clears out once you get moving down the road. He said it's been like this for a while, maybe 6 months. He has owned the truck since 150k, and he was told the previous owner had the injectors replaced. I would assume they have been. But who knows.

Before I go and order a set of injectors and jump in I thought I see what you all think. I saw no blow by smoke out of the oil fill tube. And after driving and letting set the radiator hoses are NOT rock hard. I also gave a cursory look over the turbo pipes for maybe a worn hole.

I saw a video where a guy changed out the fuel filter and also run transmission fluid through the system??? Any thoughts on that? I guess what I’m asking is should a do a little maintenance before I throw down a couple grand on injectors?

Thanks in advance. Robert

 

[OkDually]

Just when you thought nobody would ever ask another injector question. I just picked up a 2001 K3500 Crew Cab Dooley with 226,000 miles. It's a fixer upper. Nobody wanted it because it smokes bad and also has the transfer case pump rub leak.

Drives great, seems to have good power, and starts right up no problem. No active codes (my cheap code reader showed some historical codes on the ABS). Crankcase oil full. Small black oil leak underneath up at the front, couldn't see any obvious leaks, power steering hose looked wet with oil. I just crawled underneath for a few minutes. The smoke is pretty thick at idle and kind of clears out once you get moving down the road. He said it's been like this for a while, maybe 6 months. He has owned the truck since 150k, and he was told the previous owner had the injectors replaced. I would assume they have been. But who knows.

Before I go and order a set of injectors and jump in I thought I see what you all think. I saw no blow by smoke out of the oil fill tube. And after driving and letting set the radiator hoses are NOT rock hard. I also gave a cursory look over the turbo pipes for maybe a worn hole.

I saw a video where a guy changed out the fuel filter and also run transmission fluid through the system??? Any thoughts on that? I guess what I’m asking is should a do a little maintenance before I throw down a couple grand on injectors?

Thanks in advance. Robert

Congrats on your find.
OEM Injectors are a well-known issue with the LB7
I would start by investing in a monitor like an Edge CTS 3 so you can read/clear codes, check Injector balance rates and more...
You need balance rate and return flow info to determine bad injectors
Change out your air and fuel filters. I would also rebuild or replace the fuel filter head, inspect all fuel lines.
Replace any bad rubber line you find.
You can upgrade to the SAC injectors from Lincoln Diesel Specialties. Look online or contact Brent.
I would also recommend that you add a quality lift pump and extra fuel filtration.
I would not recommend that you run ATF through your fuel system...

 

[structures]

Thanks much Dually. I appreciate the help.

 

[TexasTraffic]

Yes - the LB7's have an injector issue.
Replace the bad set of injectors with SAC-style injectors and they should last a whole lot longer than the original VCO-style injectors.
Do a web search and you'll find them.

I strongly recommend replacing the HP lines to the injectors with new ones.
The LB7 design ensures that there will be rust/corrosion at the connection, and re-using the old HP fuel lines will feed that gunk to the new injectors causing an even faster fail.

 

[Spoolin'It]

Thanks much Dually. I appreciate the help.

Before you condemn the injectors just for smoking, try the fuel injector cleaning procedure thats at the top of the forum. Put on a brand new fuel filter before you run the procedure so the cleaner isnt wasted cleaning the deposits in the filter.

 

[structures]

Here's a little update and my plan. It usually smokes quite a bit on start up. After the truck set for a few days I pumped on the filter housing and it was easy to pressurize. After maybe 5 pumps it started to tighten up and I also noticed it started to get wet out of fuel heater. Fired the truck up and no obvious smoke. Idled only for a few minutes.

A few days later (last night) I got a cheap iphone monitor (dash command) and I run the truck and checked balance rates for kicks and grins. cyl 2 and 3 were out of spec like -4.1. I spent most of the evening trying to figure out how to get the balance rates to show up and called it a night. So nothing convincing with those numbers. My plan however is to reseal the filter housing and put a new filter on full of seafoam. I was going to get that AC delco cleaner x66p, but it's $100. I assume it's been discontinued.

 

[TexasTraffic]

Here's a little update and my plan. It usually smokes quite a bit on start up. After the truck set for a few days I pumped on the filter housing and it was easy to pressurize. After maybe 5 pumps it started to tighten up and I also noticed it started to get wet out of fuel heater. Fired the truck up and no obvious smoke. Idled only for a few minutes.

A few days later (last night) I got a cheap iphone monitor (dash command) and I run the truck and checked balance rates for kicks and grins. cyl 2 and 3 were out of spec like -4.1. I spent most of the evening trying to figure out how to get the balance rates to show up and called it a night. So nothing convincing with those numbers. My plan however is to reseal the filter housing and put a new filter on full of seafoam. I was going to get that AC delco cleaner x66p, but it's $100. I assume it's been discontinued.

NO!!
Seafoam is about 25% alcohol! (isopropanol)
We all know alcohol is bad news for diesel engines.

 

[OkDually]

NO!!
Seafoam is about 25% alcohol! (isopropanol)
We all know alcohol is bad news for diesel engines.

Seafoam is perfectly fine to use as an engine/fuel system treatment.
If you plan on using it for a week straight then I would say you might cause some damage..

 

[TexasTraffic]

Seafoam is perfectly fine to use as an engine/fuel system treatment.
If you plan on using it for a week straight then I would say you might cause some damage..

Ah ha!
Filling your fuel filter with Seafoam and feeding your engine a mixture of 75% mineral spirits and 25% alcohol is perfectly fine.
Got it.
I understand now.

 

[Brutus10]

Ah ha!
Filling your fuel filter with Seafoam and feeding your engine a mixture of 75% mineral spirits and 25% alcohol is perfectly fine.
Got it.
I understand now.

Seafoam is 100% petroleum based. No alcohol as you claim. I have ran it in my LBZ many times.

 

[jhornsby3]

I just had the whole fuel system rebuilt with new seals and injectors. The shop that did the work has many years in this industry. He does all the injectors for the local municipalities and major utility companies. He said the first place to start any fuel issues and smoking is the connection from hard line to flex line under the cab. That seal is a known air leak spot. He showed me that the LB7 injectors have a shoulder that air will build around. That air will cause cracking in the nozzle that leads to leaking and loading. Thus the smoking at idle or low RPMs. Also the leaking of the filter head as well.

 

[TexasTraffic]

Seafoam is 100% petroleum based. No alcohol as you claim. I have ran it in my LBZ many times.

From their own documentation, it does have alcohol.
Look at the MSDS for Seafoam.
Isopropanol is clearly listed, up to 25%
More specifically this section -
SECTION 3. COMPOSITION/INFORMATION ON INGREDIENTS

https://seafoamworks.com/uploads/2019/01/Sea-Foam-Motor-Treatment-SDS-v20161205-ENG.pdf

In past years I have looked at this and it was more specific in that It broke down the proprietary hydrocarbon mix. It was primarily mineral spirits and some naphthalene.
You can lookup the MSDS (or SDS) for most any product.

 

[structures]

So far I rebuilt the fuel filter head and changed out the fuel filter. Did the seafoam clean and let the truck idle for over an hour. After reading theferminators thread I'm pretty sure I've got 3 bad injectors. The truck really has to be warmed up for it to start smoking at idle. Attached are my numbers using dashcommand on my iphone. These numbers are after letting it warm up.

Those sac00 or sac45 injectors seem like the way to go. Lot more $$ than I thought injectors would cost.

I'll check the connections under the cab before I pull the trigger, but the connections under the hood and just the general under body is in great shape.

 

[OkDually]

So far I rebuilt the fuel filter head and changed out the fuel filter. Did the seafoam clean and let the truck idle for over an hour. After reading theferminators thread I'm pretty sure I've got 3 bad injectors. The truck really has to be warmed up for it to start smoking at idle. Attached are my numbers using dashcommand on my iphone. These numbers are after letting it warm up.

Those sac00 or sac45 injectors seem like the way to go. Lot more $$ than I thought injectors would cost.

I'll check the connections under the cab before I pull the trigger, but the connections under the hood and just the general under body is in great shape.

View attachment 638880

Looks like #2,3, and 7 are looking kinda rough

 

[TexasTraffic]

......
Those sac00 or sac45 injectors seem like the way to go. Lot more $$ than I thought injectors would cost.
......

It was a while back when I replaced with the SAC45 injectors. The SAC00 weren’t available at that time.
The SAC45s will smoke black under hard acceleration. Otherwise they drive normally.
Yes, injectors are not cheap.
Replace all 8 when you do.
When I did mine, I managed to skip the fuel rail pressure sensor and the fuel rail pressure regulator connectors when putting everything together. It started and ran, but idled very rough and loped like crazy. Those connectors are well-hidden and it took a while to find the problem. Either connector being disconnected will produce the exact same symptoms.
I recommend using some system to ensure that you remember to connect every one of the gazzillion connectors when putting it back together.