Can the HPFP cause fuel to leak into my oil?

Bmurata90

Specialist
Nov 28, 2019
58
10
0
F.L.
Ride
2010 BMW Z4 35i
I've replaced coils, plugs, and index 12 injectors. How can I narrow this down? I'm tired of changing my oil ever 1000k miles or even less because of this to try and prevent damage to my internals. The motor only has 37k miles on it. When I bought it, the injectors were leaking and I replaced them immediately. Solved all misfire codes, but oil still smells of fuel. I make sure to not take as many short trips as possible, I let the engine run for 5-10 mins before driving it, and I also WOT from time to time to heat up and dissipate the fuel from the oil. I have no idea what to do from here. Can the fuel pressure regulator cause this too? I could really use some help. Also, can black oil after an oil change smell like fuel from carbon deposits and I'm just overthinking this? I'm not trying to blow this engine up because of stupid fuel in oil.

Thanks for your time,
Brandon
 

Bmurata90

Specialist
Nov 28, 2019
58
10
0
F.L.
Ride
2010 BMW Z4 35i
Are you running super rich for some reason? Or maybe a bad burble tune?
I'm definitely running rich and I'm not sure why. I'm FBO with MHD stage 2+. No corn. Is it possible that the O2 sensors were damaged during DP install? I did most of the installs myself, but had them do the catless downpipes. This is a really good shop apparently and knowledgeable. I've dealt with them ever since I got the car 5 years ago. I didn't go to MHD stage 2+ until I got everything I needed to ensure no failure points besides this. I honestly thought replacing the injectors would solve the issue. Who knows how long those injectors were leaking before I bought the car and how many times fuel slipped by the piston rings. I'm really hoping that my piston rings aren't toast. Can a faulty HPFP cause this? It's an 09 Z4 so I wouldn't be surprised that the HPFP isn't doing well. I tried to get it recalled but stupid stealership wouldn't replace it as they saw no issues with it during testing. Drove my car for 500 miles and cost me $200 to have them not recall a known failure point. Never again. Also, when I bought the car I noticed that the exhaust tips were black as hell with less than 20k miles on the car. Again, thought it was the injectors since it solved the misfires. I also brought this up to the shop and they said "they took a lighter to the fuel cap and nothing happened". They also claimed to smell no fuel in my oil when I clearly can smell it every time I change it. Just in case I was tripping, I asked numerous people what my oil smelled like. Immediate response was "fuel". I'm in the process of yet another oil change with a blackstone report to see exactly how much fuel is in my oil. Also, my car has never burned oil. Ever. Which concerns me as I feel like it's being replaced with fuel. From what I've read, an MHD Stage 2+ tune automatically turns off the CEL for the O2 sensors. I have 2 O2 sensor faults right after I clear the codes. Also, I did a cold start and revved up my engine to 1.5k RPM and the RPM was bouncing about 300 to 400 RPM per second for a couple minutes. Did I get a faulty set of index 12s from FCP? Car idles and starts up just fine though. A few days ago there was one time I started up my car while swapping tires and the ignition was jumpy, sluggish, or whatever you wanna call it. There was only 1 time that the CEL didn't come on for about an hour after clearing them. I'm no expert on this matter and could really use some advice.
 
Last edited:

Bmurata90

Specialist
Nov 28, 2019
58
10
0
F.L.
Ride
2010 BMW Z4 35i
I'm definitely running rich and I'm not sure why. I'm FBO with MHD stage 2+. No corn. Is it possible that the O2 sensors were damaged during DP install? This is a really good shop apparently and knowledgeable. I've dealt with them ever since I got the car 5 years ago. I didn't go to MHD stage 2+ until I got everything I needed to ensure no failure points besides this. I honestly thought replacing the injectors would solve the issue. Who knows how long those injectors were leaking before I bought the car and how many times fuel slipped by the piston rings. I'm really hoping that my piston rings aren't toast. Can a faulty HPFP cause this? It's an 09 Z4 so I wouldn't be surprised that the HPFP isn't doing well. I tried to get it recalled but stupid stealership wouldn't replace it as they saw no issues with it during testing. Drove my car for 500 miles and cost me $200 to have them not recall a known failure point. Never again. Also, when I bought the car I noticed that the exhaust tips were black as hell with less than 20k miles on the car. Again, thought it was the injectors since it solved the misfires. I also brought this up to the shop and they said "they took a lighter to the fuel cap and nothing happened". They also claimed to smell no fuel in my oil when I clearly can smell it every time I change it. Just in case I was tripping, I asked numerous people what my oil smelled like. Immediate response was "fuel". I'm in the process of yet another oil change with a blackstone report to see exactly how much fuel is in my oil. Also, my car has never burned oil. Ever. Which concerns me as I feel like it's being replaced with fuel. From what I've read, an MHD Stage 2+ tune automatically turns off the CEL for the O2 sensors. I have 2 O2 sensor faults right after I clear the codes. Also, I did a cold start and revved up my engine to 1.5k RPM and the RPM was bouncing about 300 to 400 RPM per second for a couple minutes. Did I get a faulty set of index 12s from FCP? Car idles and starts up just fine though. A few days ago there was one time I started up my car while swapping tires and the ignition was jumpy, sluggish, or whatever you wanna call it. There was only 1 time that the CEL didn't come on for about an hour after clearing them. I'm no expert on this matter and could really use some advice.
Also, I have stock burbles still and this was an issue prior to MHD.
 

ShocknAwe

Captain
Jan 24, 2018
1,491
1
737
0
Charleston, SC
Ride
N54/3 1er ///Mutt
Need to leak test or just work through all your lines and seals PCV etc one by one... Extra air will cause you to run super rich, likely has ruined your O2s, doubt the O2 sensors are the cause.

Log with MHD if you can, emphasis on lpfp rail stft AFR