Injector cleaning

[Pure Diesel]

Injector cleaning story

I’ve got 221K total miles on this engine (2006 LLY). I’ve put 114K of that since the transplant. I’ve always been disappointed with the fuel mileage compared to the old LB7. Been noticing more & more how the injectors are getting noisier & puffing black smoke, under certain conditions. This is usually when I’m at 60mph 6th gear and push the accelerator pedal. When towing it’s puffing a lot more than before. The throttle response also seemed to be laggy. It felt like the truck was hesitating before it would get going.

Now I wished I had done the balance rates before I did this work, but didn’t have anyone at the time to do it. I bought the AC-DELCO 10-3015 top engine & fuel injector cleaner (32oz.) I mixed it with a ½ gal of Diesel and ran it through the system. This was via the return and feed line. It took about 1-1/2 hrs. to do this. I then went on a test drive to see how it worked. It had some severe injector knocking and black exhaust. I ran the truck hard, easy & hard for about 30 minutes (20 miles). Everything cleared out and this truck is amazingly quiet, way smoother and the throttle response is back. Fast forward 1-1/2 months, 4-tanks of fuel & about 2,600 miles. My hand calculated mileage has gone up almost 2 MPG. I was averaging between 15-15.5 MPG before and now I’m at 17.43 MPG for the last three tanks (mixed city/Fwy). My 4th tank of fuel I did my double tow (10k 5th & 3k side x side trailer). I got a hand calculated 12.72 MPG for this trip. This trip was 190 miles and the first 90 miles was into a 25-30 MPH head wind. I’ve done this same towing trip many times before and the mileage varied between 9-11 MPG.

I thought I’d throw this out here and if helps others great. So far the net results are way more than I expected. I plan on doing this once a year to maintain the injector system. If this is a no-no, someone chime in. I've also added fuel injector additive every tank since I bought this truck brand new.

 

[2004LB7]

it's definitely not a problem doing often or once a year as you intend but many who have done as you did found it didn't last. unusually needing to clean you injectors means they are going n their last leg and you should plan on replacing them in the near future.

please keep up updated on how they are doing over time. it would be nice to know how yours turns out

 

[sneaky98gt]

I did mine a few weeks ago, and it made no difference at all. Engine noise, fuel mileage, balance rates....nada. Not a single lick of difference.

Strangely, during the procedure, all of the balance rates came down drastically. I was doing it to see if it'd help a -4.5 balance rate injector and corresponding idle hazing. When I shut the truck off just as it was emptying the container, the -4.5 injector was at -0.8, and the worst one of all 8 was like 1.2. However, I drove the truck for maybe 5 minutes, then stopped and checked them again: they were back to within 0.1-0.2 of what they were before. Not a single bit of change.

No clue why they all came down so much during the cleaning. I've let the truck idle for like 30-45 minutes since then just to duplicate the situation, thinking there was something going on in the tune regarding rail pressure or coolant temp. Nope. They sat steady (at the bad rates) for the entire time. So still no explanation.

 

[Chevy1925]

the cleaner will act different in an injector and fire differently compared to diesel fuel so im not surprised the balance rates changed.

remember, a balance rate is the balance of power between cylinders, not the actual injector balance. thats why compression between cylinders can throw off balance rates as well.

 

[sneaky98gt]

the cleaner will act different in an injector and fire differently compared to diesel fuel so im not surprised the balance rates changed.

remember, a balance rate is the balance of power between cylinders, not the actual injector balance. thats why compression between cylinders can throw off balance rates as well.

That was the only thing I could think of, but I wouldn't have guessed it'd make that drastic of a difference, especially since it was only about 15% of the mixture.

 

[fl0w3n]

the cleaner will act different in an injector and fire differently compared to diesel fuel so im not surprised the balance rates changed.

remember, a balance rate is the balance of power between cylinders, not the actual injector balance. thats why compression between cylinders can throw off balance rates as well.

Interesting... I no longer have the truck, but I think you just answered why my brand new SAC45's in the 02 had some pretty far off balance rates.

Considering DD'ing 350k mile LB7?

Saw the 04 LB7 I mentioned, the thing is super dang clean. Almost immaculate paint. Interior is super clean, except tear on driver seat. Bone stock except a stereo. Not even an exhaust. Runs and idles super smooth, pulls good. But Tech 2 tells a different story, looks like injectors are on...

www.duramaxdiesels.com

 

[Pure Diesel]

Update.
Have put another 2243 miles and 4 tanks of fuel.
First tank mpg was 15.61 with 75% city and 25% hwy.
Second tank mpg was 13.68 50% city and 50% hwy. I did do a double out to Johnson Valley for King of the Hammers. Pretty much flat driving not much for hills.
Third tank mpg was 10.07 and this was all double towing nothing else. The reason the mileage is crap is due to 100 miles of about 40 mile/hour head wind. It's still better than what I've gotten before for this trip when there is a bad head wind. I've had 7-8mpg before doing this run.
Fourth tank mpg was 16.51 and this was with 60% city and 40% hwy.

The truck is still running and sounding better than before the treatment.

 

[baggedLB7]

Not sure if anyone knows this or not but if you put in Saturn vue top engine cleaner, it pulls up the same part number but only cost 17 and change.

 

[sneaky98gt]

Not sure if anyone knows this or not but if you put in Saturn vue top engine cleaner, it pulls up the same part number but only cost 17 and change.

Are you sure about that? Can you share a link?

I'm pretty sure that the "X66P Upper Engine and Fuel Injector Cleaner", which is what's been prescribed for Duramax injectors since at least 2010, is no longer sold by GM. There is a low-VOC replacement for that (of which I don't have a part number handy) that's a more normal price, but most people say it's not as potent as the X66P. That's why the few bottles of it that you can find are $80+.

However, BMW sells an injector cleaner that IS the exact same as the X66P. Part number 82140428376. I picked some up from the local BMW dealership for ~$25 including tax. It's in the same bottle, same color, and the rear label matches word-for-word other than the AC Delco label. I didn't look it up myself, but other sources online state that the MSDS's show the same active ingredients.

I ran several tanks of fuel through after doing the cleaner on mine. Made no difference whatsoever. Fuel mileage, balance rates, idle haze, engine 'smoothness'. All the same as before. I think that if, for some reason, you have some carbon deposits obstructing the nozzle orifices, then the cleaner may make a difference. But if the injectors are just worn out and/or the pintle isn't sealing up the orifices, no amount of cleaner will fix that.

 

[baggedLB7]

My comment is based off of the part number the original poster posted about.
AC-DELCO 10-3015

 

[2012lml]

Injector cleaning story

I’ve got 221K total miles on this engine (2006 LLY). I’ve put 114K of that since the transplant. I’ve always been disappointed with the fuel mileage compared to the old LB7. Been noticing more & more how the injectors are getting noisier & puffing black smoke, under certain conditions. This is usually when I’m at 60mph 6th gear and push the accelerator pedal. When towing it’s puffing a lot more than before. The throttle response also seemed to be laggy. It felt like the truck was hesitating before it would get going.

Now I wished I had done the balance rates before I did this work, but didn’t have anyone at the time to do it. I bought the AC-DELCO 10-3015 top engine & fuel injector cleaner (32oz.) I mixed it with a ½ gal of Diesel and ran it through the system. This was via the return and feed line. It took about 1-1/2 hrs. to do this. I then went on a test drive to see how it worked. It had some severe injector knocking and black exhaust. I ran the truck hard, easy & hard for about 30 minutes (20 miles). Everything cleared out and this truck is amazingly quiet, way smoother and the throttle response is back. Fast forward 1-1/2 months, 4-tanks of fuel & about 2,600 miles. My hand calculated mileage has gone up almost 2 MPG. I was averaging between 15-15.5 MPG before and now I’m at 17.43 MPG for the last three tanks (mixed city/Fwy). My 4th tank of fuel I did my double tow (10k 5th & 3k side x side trailer). I got a hand calculated 12.72 MPG for this trip. This trip was 190 miles and the first 90 miles was into a 25-30 MPH head wind. I’ve done this same towing trip many times before and the mileage varied between 9-11 MPG.

I thought I’d throw this out here and if helps others great. So far the net results are way more than I expected. I plan on doing this once a year to maintain the injector system. If this is a no-no, someone chime in. I've also added fuel injector additive every tank since I bought this truck brand new.

I'm about to do this treatment. Having a hard time figuring out how much of the cleaner to use with the 1/2 gallon of diesel. Just wanted to confirm that you used the entire 32 oz in 1/2 gallon of diesel

 

[Pure Diesel]

Yes, I put the entire 32 oz in with the 1/2 gallon of fuel.

 

[Bdsankey]

I've always poured the cleaner into a 1 gallon container then topped it up with diesel and let the truck run until it died from fuel starvation/running the jug out of fuel.