2015 Tahoe P0172 P1075 Fuel in Oil

[Mmm555]

New the the forum and looking for some advice to make sure I’m thinking right about a problem and don’t get worked by the shop.

Check engine light comes on fairly regularly. Throws PO172 and PO175 codes. There’s fuel getting into the oil. Truck dielsels for a few seconds after shutting off. Car rough idles a bit and has a slow pickup and hard down shifts at times when breaking. Exhaust has a fuel like smell. I swapped in new OEM MAF sensor and got oil changed to check those boxes. Based on reading here, it sounds like high-pressure fuel pump is a common problem, especially when fuel in oil. Could bad 02 sensors or fuel injectors Or even faulty ECM be the issue? Of course more info and testing needed to be sure but anyone have any thoughts?

 

[2017sltXL]

Have you checked your fuel trims? Good place to start, if you have a scanner or something that can monitor those.
Here is a good video.

If it's the HPFP, it's not a horrible job. The worst part is getting the rear wire loom clips loose from the back of the intake vanity cover.
It's actually easier to just loosen that cover, and once the intake bolts are loose, just lift the cover and slide the intake out.
Once that is done it's a little easier to remove those rear wire loom clips.
Tons of good vids on replacing the HPFP

 

[Mmm555]

Thanks a ton. Assuming fuel trims are running super low -10 or lower, probably a safe bet it’s HPFP right?

 

[Fless]

Thanks a ton. Assuming fuel trims are running super low -10 or lower, probably a safe bet it’s HPFP right?

Note that "super low" fuel trims would be between -5% and +5%, which means that the PCM is removing or adding, respectively, a small percentage of fuel to the typical amount. It's not an absolute number, but should be within a small range centered around zero.

 

[Mmm555]

Have you checked your fuel trims? Good place to start, if you have a scanner or something that can monitor those.
Here is a good video.

If it's the HPFP, it's not a horrible job. The worst part is getting the rear wire loom clips loose from the back of the intake vanity cover.
It's actually easier to just loosen that cover, and once the intake bolts are loose, just lift the cover and slide the intake out.
Once that is done it's a little easier to remove those rear wire loom clips.
Tons of good vids on replacing the HPFP

Thanks a ton for the video. Checked the fuel trims. All running very very rich: -35 long term and -25 short term at idle. MAF numbers are good around 5.3 g/s. I checked PCV valve and it seems fine. I am getting close to certain its the HPFP given the codes and fuel getting into the oil and how common that issue is (small chance it is potentially injector(s) or some broader ECM issue). 02 Sensors also reading rich. It just got too hot in Florida to work in my driveway (and I know this is probably just outside of my comfort zone), so I am going to bite the bullet and take it in to the shop

 

[Mmm555]

To close the loop here, I had to take it to a dealer since a number of local mechanics wouldn’t touch it. Turns out it was, in fact, the high-pressure fuel pump. Replace that and running right now. Although $1800 later…

 

[tom3]

How many miles on this machine? This used to be a problem with the 4 cylinder Eqs.and Terrains, out of warranty, destroyed many engines.

 

[Mmm555]

2015 Tahoe LTZ. 5.3L. 111k miles

 

[AJ_Victory_27]

How many miles on this machine? This used to be a problem with the 4 cylinder Eqs.and Terrains, out of warranty, destroyed many engines.

What was the indication/precursor to engine failure in the 4 cyl Equinox? I just read the thread, smelled an hint of fuel in the oil and immediately made an oil change appt after experiencing the after shut off dieseling and P0172&P0175 codes. Took out the 87 Perf tune on the Diablo tuner and set her back to stock and everything seems normal again, no codes and no dieseling. Will continue to monitor. Thanks for the detailed thread.

 

[the 18th letter]

What was the indication/precursor to engine failure in the 4 cyl Equinox? I just read the thread, smelled an hint of fuel in the oil and immediately made an oil change appt after experiencing the after shut off dieseling and P0172&P0175 codes. Took out the 87 Perf tune on the Diablo tuner and set her back to stock and everything seems normal again, no codes and no dieseling. Will continue to monitor. Thanks for the detailed thread.

Am I reading correctly that your tune caused the hpfp malfunction?

 

[jaxscuby]

could be stuck injector.
had a coworkers silverado with the same codes, my cheap code reader only listed
the cels and 0300 for misfire due to the injector.

took it to a shop with hi-end scanner and it identified which injector was causing the cels.