tech2

I probably should stop helping you then.

skiziks

My selling dealer stopped helping me, beginning to feel abandoned.

Although I am trying to be optimistic about the outcome after Wednesday's appointment advice from everywhere is always welcome.

Hopefully, this dealer will outperform my selling dealer. Fingers crossed.

tech2

Usually for the i4, it is the injection pump. I Thought you had the v6? The repairs I have done for injectors were on the v6. What does the lab list for allowable fuel in oil spec?

skiziks

The Blackstone Lab report has a column: "Values Should Be".
For "Fuel %" they have "<2.0"

The high pressure pump was replaced last October. Apparently if that doesn't solve the fuel problem the selling dealer service department is bankrupt for alternative fixes.
Tomorrow we shall see if a different dealer's service dept. have other ideas. If not then it means changing the oil every 3k miles.

dtro1

I have used Blackstone for 7 years on my Duramax trucks (2) with a total of 300,000 + miles. I am using Mobil synthetic oil and was very comfortable going 22,000 on each oil changes (with filter at 5,000) with Blackstone results and their good service.
NOTE: If you are religious about using oil sampling be sure to ask for "TBN ANALYSIS" that will report what levels of the oil additive package remain and how far you can go. (assuming wear elements are good) This is a little extra cost with Blackstone, but it's the only way to asses additive package wear.

tech2

What are the fuel trim values at? When you check the dipstick; is the oil diluted and have a fuel smell?

skiziks

I don't know what trim values are. But yes, I smell fuel on the dipstick.
Blackstone report shows a dilution of the oil.
The very first clue to a potential problem was the dip stick showed over full after driving a couple of thousand miles.
I had changed the oil, let it drain for hours, installed 5 quarts. But the next oil change, I measured what drained and it was over 5 quarts.

tech2

if unmetered fuel is getting into the engine, this will enriching the fuel/air ratio. The oxygen sensor detect this and will cut the amount of fuel metered out by the injectors. This fuel cut is shown on the scan tool as fuel trim. Ideal is 0% +/- 10%. When the system is at its adaptive maximum (the fuel trim is so askew the system cannot compensate and correct it) a dtc will set. Is the check engine light illuminated?


give the shop a copy of your analysis. Don't bring the car in after your oil change or everything will appear normal. bring it in when your ready to change the oil and the dilution is easy to detect.

skiziks

Brought the NOX in yesterday with the last two UOA reports and without changing the oil first, 68% still on the OLM. The techs tested pressures, trim, injectors, and some other things that I've forgotten.

The pressure drop was minimal, within the specs they obtained from multiple communications with factory engineers during the day.

They had the vehicle all day trying to find or verify what the UOA reports showed. But, alas, all their efforts resulted in everything falling within acceptable limits.

I sincerely believe that they gave it their best shot.

Future oil changes will be performed by me. Measuring what drains and replacing exactly 5 quarts. The UOA will continue also. Sooner, but hopefully later, premature wear will develop and there will be these documents to fall back on. They discouraged waiting to change the oil until the OLM read "0", 20% would be their max recommendation.

The OLM has never reached "0" since I've owned this vehicle. The oil has been changed at least 6 times within the past year, 16k miles.

Meanwhile, to solve another annoyance, the dealer will replace the rack and pinion assembly. After at least a half hour of straight highway driving the steering will feel notchy or have a slight resistance to being turned off of dead center.

There is a bulletin about this: #PIT-4992C
NHTSA Reference # 10043944

57chevythunder

WOW, reading through this thread is almost scarey,,,, What a bummer of a problem!! -I sure do hope "the right/final" solution is found.

Quick question for "tech2": I have read that even the 3.6 V-6 with it's DI has a reputation for having higher than reasonable levels of fuel contamination in the engine oil. It that really true ??

I guess as an old "ex-mechanic", I don't quite see why this new DI should be any worse than any other "fueling method." I surely would have thought that now with the new "high technology" being what it is, and the computers so closely controlling everything, it would actually be "cleaner." (that's what I get for thinking, I guess,,,)

Of course I suppose if for some reason the injectors were being "overwhelmed" by fuel pressures too high for them to control, then maybe that would be a problem ?? -just wondering,,

-be sure to let us know what solved the problem,,
Thanks !!