I would think it's that singular injector that you see jumping around has either worn or is stuck and dumping fuel into the cylinder and the excess is causing your problem. One cheap way to test it is to buy some nuts to block injector lines off amazon (a six pack is like 20$) and then block that injector at the rail, start it up and observe for changes

 

Are these special fittings or just standard hardware. I don’t follow fully and would like to try this to be 100% sure , turning the smoke on and off

 

Stuck injector.

 

Looks like the typical LB7 smoke/haze due to return rates that would probably be out of spec if you test them. Balance rates only tell part of the story. But I would say you’ll be needing to put injectors in it

 

good point on balancing rates only being one dimension of injector performance. I

 

My 2003 LB7 has hazing and needs new injectors. SAC25 or SAC45, and roughly $2000.

 

I think I’m going to go with SAC style myself. Seems like you got to go oversized. Read about many problems with “00” stock size

 

So I’m exactly 3/8 through changing my injectors. ( 1 was giving me a hard time on the passenger side, so I jumped back over to drivers)
I noticed different colors to the injectors. New to diesels - I wonder if you could read the color like you would a spark plug to indicate how that cylinder is running.

I noticed 1 in particular has a different color to the crud that was on it.

 

If you're still having a hard time getting that one out, it's probably because it was dribbling pretty bad and has carbon built up around the nozzle that's keeping it from coming through the hole in the cup. You can try a couple of things to get it out.

Slowly twist back and forth with light upward pressure to break the crud loose. I have down this once and it took a while but worked and did not dislodge the cup - saving me even more work.

I haven't tried this way but seems like it ought to work: Pour a little Sea Foam into the cup. Now that the injector is not pinned down to the compression washer, the Sea Foam should run down the injector tip and loosen that crud up. Sea Foam is made to clean carbon deposits in your combustion chamber. Usually, you mix it into the fuel tank but I see no reason at all that you couldn't use it like this - sparingly. I plan to try this myself if I ever have that problem again.

 

I appreciate this tip. It is the injector in cylinder #2 - the one that was most negatively imbalanced compared to the rest. I think you are spot on. I sprayed some pb blaster on it. I’m going to give it another go tomorrow

 

Maybe it will help someone one day - the rear- most injectors on both passenger and driver side gave me a tough time removing them.

How I got them off was tightening a line on them and, using a wrench for leverage, twisted them Cw, ccw while pulling like hell. On the passenger side I was able to use a small pry bar to just apply some gentle steady upward pressure. I got both out without the cups so I felt like I won for the day.

 

Yeah, the injectors that were hard to get out were the reasons for your hazing and poor mpg. The needle / seat interface inside the injector gets "sandblasted" by tiny particles in diesel fuel that are smaller than the finest filter media available.

With pressures around 26,000 psi, it's kind of easy to understand what's happening and over time, the needle / seat starts leaking and dribbling fuel into the combustion chamber causing hazing because you're over-fueling and carbon build-up because there is raw fuel on the nozzle at combustion and it's not atomized like fuel injected at 26k psi and thus does not fully combust / burn and leaves a carbon "crust" on the tip.

After reading and reading and researching this problem for the past 21 years (my first set of injectors failed 2 years after I bought my truck) I've tried a few things. I've had my injectors replaced 5 times so far. Twice under the 7 year, 200k mile warranty and did it 3 times myself. Nothing I've tried really prolonged my injector life. Every set has been replaced at around 80k miles - give or take a few thousand miles. EXCEPT my current set! I now have 95k miles on this set and while my mpg is currently down a little, I'm not hazing and I'm a ways off the 2 mpg loss I normally see when it's time to replace injectors. I'm down about .5 - .7 mpg right now.

What did I do differently this time? I added a second fuel filter back by the tank. I had added a lift pump years ago and while I love the thing and how much easier it makes bleeding fuel filters and such, it didn't prolong my injector life a bit. I added the extra fuel filter probably about 40k-50k miles into this set of injectors so hopefully, next set will last even longer. Of note though, without a lift pump, I doubt even a strong CP3 would be able to pull sufficient fuel through both filters to keep the truck running right.

To be a little more specific about my current filter setup: I am running OEM Delco filters on the factory filter-head under the hood. I am running Donaldson P553203 filters in the back. I tried the Donaldson up front for a while all by itself. That didn't help but 2 separate filters seems to have done the trick. When I was running the single filter, I was changing it every 10k miles. Now that I'm running 2 filters, I change the OEM one under the hood every 20k miles and the Donaldson every 10k miles. I just figured that the one under the hood is now getting pre-filtered fuel and therefore should last longer. Seems to be working. Again, there is no filter media out there that will catch all of these tiny particles and keep them from sand-blasting the insides of your injectors but it appears that 2 separate filters at least catches more than a single filter. Enough to actually make a difference. I intentionally went with 2 different brand filters thinking that maybe the combo of 2 different filter medias and 2 different filter designs and manufacturing may be more effective than using 2 of the same brand and part number. I have no data at this point to tell me one way or another - I'm just happy as hell to be running the same injectors for 15k miles (so far) longer than any set has lasted for the past 23 years.

 

Correction: 105,000 miles on these injectors now. I checked my repair log. These injectors were installed at 365k miles. So I'm 25k miles on the plus side now. I'll take it!

 

Question. Did you replace your injectors with the new improved style SAC injectors or the OEM style VCO injectors? Thanks, Chris.

 

Following up on this -

No more smoke !

After the fresh injectors I primed her up and she fired up without too much drama.

No smoke initially but I got to say I went through a few layers of hell when I went for a test drive. For some reason i got something coming out of the tailpipe. It looked a lot like the white smoke of before. But after coming up to operational temperature it was gone. I’ve put over 200 miles on the truck and I haven’t seen any sign of the smoke. It idles smoother, that little hiccup is gone, and I like to think it runs better.

thanks for all the help.

 

Congratulations on fixing your truck. What injectors did you buy VCO or SAC injectors? Also where did you buy them from & total cost? Thanks, Chris.

 

The smoke was probably any stuff you sprayed in the cups to loosen carbon buildup or maybe even some antifreeze left in the combustion chamber from all the work you did. As long as it's not smoking now, pat yourself on the back! Lot of damn work!!

 

I think you are right and thank you! You ain’t lying about a lot of work

 

I had an LB7 last year that I did injectors and cp3 on that smoked for nearly 30minutes while the exhaust and and everything that was coated inside the manifolds/uppipes/turbo/downpipe all cleared out and burned off. It’s amazing how much that stuff can stick in there and take to burn off

 

Thanks for letting us know about the left over fuel in the exhaust smoking. I would have been thinking that something was not installed properly when I do them in the future. Thanks, Chris.

 

I am on my third set of injectors on my 04. The truck only has 220,000. This time I put Stock S&S SAC injectors in her. Truck runs great. It fixed the issues, but so did the Bosch VOC's for a short time. The only issue I have now is I have lost 4-5 mpg's when running empty. I was getting around 20 mpg before, now around 14-16.
When pulling a tandem utility trailer with a small zero-turn, I'm getting 12-13 mpg. I was getting around 16 mpg. When pulling my 40 foot fifth wheel loaded with Harleys, fuel, water and gear I get the same as I always did: 10-11 mpg. Does anyone have an idea what happened?

 

Something changed, but what? I know that S&S makes good injectors and can't imagine that the cause is only the injectors themselves, assuming the product choice was at the very least close to stock, not 30% - 50% over.

 

Yes. Stock injectors.

 

I have no first hand experience however I will summarize what I have gathered from my hours of research on the S&S -stock sized- SAC injectors… problems.
I have read numerous accounts on forums about fuel mileage being negatively affected. I think you are #3 or #4. I reached out to S&S and didn’t get a warm fuzzy feeling from their response.
For whatever reason, I think the 00 SAC injectors that were supposed to solve all the problems for LB7s never panned out. Look at the warranty they offer and compare it to NEW OEM Bosch… it’s shorter.
Again, not knowing the reason, but the 45 SAC seem tried and true IF you need the extra fuel.

When you reach out to the independent vendors, their opinions on the matter seem to be for near stock applications, stick to New Bosch.