2001 Injectors - Self Healing?

My truck now has about 115,000 miles on it. A couple of years ago this truck began setting injector related trouble codes - like P0302 and sometimes P0089/93. This code setting process was getting worse as time passed - over about a 2-year time period. It looked like the engine had a bad #2 injector. The engine also ran a little rough and we frequently smelled the acrid gases of incomplete combustion in the cab. I began preparing for an injector replacement.

For most of the truck's life I had used some sort of fuel treatment - mostly Stanadyne and/or Power Service. I also used some ATF. Once the code setting began I stopped adding anything to the fuel. Then... the problem went away all on its own.

It's been more than 6 months since the codes went away and the engine returned to running smoothly and normally.

Some could argue that the ATF might have fouled the injectors. Maybe. I also think the problem could be attributed to an easy life in a cool environment. I know that the 6.2L/6.5L diesels I've owned all ran smoother after a towing trip where the engine was worked hard or a period of time and number of miles. I know that hotter combustion temperatures and higher fuel flow rates help clean the injectors, though I haven't towed with this '01 GMC for quite a while.

We'll see what develops....

Had the same experience, documented elsewhere here in TDP forums with my 2001 K2500HD. It got the first warranty set at 170k miles, and only 80k or so more was smoking at idle. I'd treat the fuel with ATF, and the smoking would go away for a few thousand miles. That was still the case, no worse, no better at 280k or so when I sold her and last I knew she was north of 300K and still running like a top.

A couple of years ago I received a phone call from a member who was a diesel shop owner.

He told me that one of his Duramax owning customers added a little ATF religiously to every tank of fuel. For some reason his truck came in for an injector replacement, and the shop owner had an opportunity to carefully examine the injectors, knowing about the ATF use.

What he reported was that the moving parts of the injectors were clean and looked normal. He said that injectors from trucks that were run without any fuel treatment always produced a film of residue on the moving parts that may have in some cases caused the injector failure.

His conclusion.... Adding ATF helped to keep the injectors clean.

Quote:

---

Originally Posted by More Power

.... I also think the problem could be attributed to an easy life in a cool environment. I know that the 6.2L/6.5L diesels I've owned all ran smoother after a towing trip where the engine was worked hard or a period of time and number of miles. I know that hotter combustion temperatures and higher fuel flow rates help clean the injectors, though I haven't towed with this '01 GMC for quite a while.....

---

FWIW, my '04 LB7 is my first high mileage (115k) diesel, and I find it seems to run more smoothly towing the 38' trailer than it does bobtailing around town.

Back a couple of decades ago, a local trucker and I talked about my 6.2L diesel pickup that I owned at the time. He told me then that diesels were meant to work hard and that a life of leisure isn't good for a diesel engine. I chalked it up to his experience being all with OTR trucking and not light-duty diesels.

While I think modern high-pressure common rail consumer diesels are still different than over the road truck diesels, there may be some truth to the notion that diesels need to work hard - at least every now and then...

When you hook the trailer to the 2001 the P0093 will likely come back. It tends to be load related.

Quote:

---

Originally Posted by Kennedy

When you hook the trailer to the 2001 the P0093 will likely come back. It tends to be load related.

---

You're likely right. I have no illusions that whatever caused the original codes has permanently fixed itself. It's more an interesting factoid in the grand scheme of things.

The P0093 is easily fixed with ECM programming and no hard parts provided your injectors are not really bad. Even then it seems once the P0093 bug bites parts changing will not fix it.

Does 2 cycle oil work as well as ATF ??

Quote:

---

Originally Posted by Roy W

Does 2 cycle oil work as well as ATF ??

---

I know that synthetic 2-cycle oil tends to keep pistons, rings and combustion areas clean in a 2-cycle engine. This is partly because of the higher combustion temperature of synthetic when compared to petroleum based 2-cycle oil. There may be other additives in synthetic that help too.

Better results through chemistry.... The chemistry used in approved diesel fuel additives provides better lubricity and cleaning than do urban legend type fuel treatments. And, when treating according to directions, could be less expensive over the long haul.

That said, I don't have a problem with those who want to use ATF or 2-cycle oil as a fuel treatment. I just think there are better choices.

Quote:

---

Originally Posted by More Power

Better results through chemistry.... The chemistry used in approved diesel fuel additives provides better lubricity and cleaning than do urban legend type fuel treatments. And, when treating according to directions, could be less expensive over the long haul.

---

Well said.

Regarding fuel additives, do you believe lubricity is the greater concern? Or is the additive's cleaning ability as important?

Reason I'm asking: One new engine supplier (known to this forum) mentioned to me that I could use "low-ash, 2-cycle snowmobile oil" as a good fuel lubricity additive. (aka: "snowmachine" oil, here in Alaska) From what little I've read, it should meet API-TC ratings (not merely TC-W3). If it's a mineral-based oil, it's supposed to stay well-mixed with diesel in cold weather.

Other well-respected product suppliers (also known to this forum) use diesel fuel treatments with lubricity additives included.

On YouTube, there are some "lubricity tests" utilizing a simulated bearing being skidded across a rotating race, with force being applied and measured using a torque wrench lever. Scarring of the bearing surface is less with certain products. I'm left wondering if these tests are even applicable for fuel treatment lubricity purposes.

Thought the good folks, here, would know best.