DallasDave

I was informed by a fellow forum member, that the reason I have had three new O2 sensors may be due to fuel contaminating my oil. A quick removal of my oil filler cap and a big whiff definitely smells of fuel. So now the adventure starts. New HPFPs are anywhere from $280 to $900/each. I don’t want to go cheap, but I don’t want to waste money either. I plan on doing the repair myself and have a few questions.

1. Can someone confirm that I have the correct part number with 079-127-025-AJ? This one sells for $750.00 each.

2. Is there a lower cost option available that should be considered?

3. Should both units be replaced, or shall I attempt to determine which one seems to be the problem and just replace it?

4. Are there any replacement tips that should be shared? I assume disconnecting the battery is needed, but what’s the best way to relieve the fuel pressure without making a big mess?

Any guidance will be greatly appreciated. BTW, my car is a 2016 with ~90,000 miles and the fuel pumps have never been replaced before.

ScaryMoldyToast

I know I already responded, but just making the info more available.

It looks like the original part number (that shipped with our car) was "079127025AK", new part number is what you have there "079127025AJ". eEuroparts lists the old part number but should still be correct.
https://parts.audiusa.com/p/70048164...27-025-AJ.html
https://eeuroparts.com/product/delphi/HM10039

I can grab the official ELSA instructions when I get back from work. Fingers crossed my oil doesn't smell like gas.

DallasDave

Thanks for posting. The difference in price for the two links you mentioned is $260/pump. This is a great example of my dilemma, which one(s) to get. I also found a Hitachi unit that sell for under $300

Mike911A8

I just responded on the other thread, and to restate here, I experienced two O2 sensor failures on my 2018 S8+ at about 45,000 miles. The dealer couldn’t figure out the source of the problem, there were no codes other than the O2 codes. The dealer techs conferred with the technical support people at Audi, who told them to smell the oil for the smell of gasoline, which they did , and they did smell gas in the oil, and based on that, the HPFP was replaced. And I changed the oil! That was about three thousand miles ago, and my S8 has run perfectly ever since.

I thought it was significant that there were no codes identifying the HPFP as malfunctioning. Mike

statgator

DallasDave,

Please put the final resolution here if you don't mind. If the HPFP is the issue and didn't throw any codes would be really interesting.

I have an F150 that runs amazing but has the smell of fuel in the oil reservoir. I barely drive it and I was told that the cause is from lots of short cycles and not giving the PCV system time to pull the fuel out of the oil along with the moisture.

DallasDave

Thanks for adding your comments. I have spoken with a couple of my buddies (all car enthusiasts) and here's what they recommend. Replace the O2 sensor to eliminate the P2096 code. Although it hasn't been that long ago, replace the spark plugs with NGK units (I currently have APR spark plugs) gapped at 0.024". Once both of those are done, delete call codes and get the oil changed. Drive for several hundred miles or even more.

Check for fuel smell again in the oil. If it still occurs, go to the HPFP replacements (both, not a single unit). If there is no longer the fuel smell, attribute it to a faulty O2 sensor and/or bad spark plugs.

The new plugs and sensor will be installed this weekend and an oil change forthcoming!

ScaryMoldyToast

Took a whiff of my oil when I got home, thank god it's only oil. Started to second guess myself too, but it's oil.

Dallas here is the procedure to remove the high pressure fuel pump, it doesn't look too bad, it does say you need to turn the engine over by hand though.

A8L_New_England

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Feeling lucky? https://www.aliexpress.us/item/3256804470605617.html
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$200.
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DallasDave

Ahhh, don't share that with me!! AliExpress? LOL

A8L_New_England

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Many parts on these cars are made in China, OEM. I kind of gave up on that a while back. Do we even know who is the OEM?
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It would be a crap shoot, though
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