Hello Scott,
I have a BMW 328i N20 F30 2016 with 59k miles on it, I bought my car from the dealership used with 24k miles and always made around 450-500 miles per tank of gas. Around 6 months ago I had to leave my car at my driveway for about a month and a half just standing there on half a gas tank. Came back to it, and for the next few months I was getting only 220 miles with a full tank. The car had a rough idle and it went into limp mode twice, I checked the code and it gave me a P0087 code. I changed the fuel rail sensor and still the same outcome.
I took it to the dealership hoping they would solve this issue (knowing they would suck every penny out of me). I get a call back from them saying it needed a software UPDATE. Got the car back and STILL!!!! 220 miles per full tank. I do not know what to do anymore, I want to try and replace the low pressure fuel pump see if that works but, if not I would be lost. I am wasting about $100 every week of gas.
Thanks Scotty big fan.
before replacing parts, make sure they're actually broken. Get a fuel pressure gauge on it.
I tried putting a pressure gauge on it but, either I don't know where the check valve or test valve is on my vehicle which I have tried looking for or it just doesn't have one.
I was thinking it might be a Bad OX sensor
a diagnostic tool will show that
Quick update: Ended up taking it back to the dealership to get it checked out since they got all the fancy software and special tools. After 5 days they call me back saying they can't find anything wrong with the vehicle .
I wanna guess its a part that is probably not showing any faults and will fail in the future.
Start simple. You said -
I had to leave my car at my driveway for about a month and a half just standing there
Check your air filter to verify it isn’t clogged/dirty.
Since you have a P0087 code, check the fuel lines & fuel filter too, incase something damaged them during your absence -
https://www.carobdcode.com/p0087-bmw-fuel-rail-system-pressure-too-low
Quick update: Ended up taking it back to the dealership to get it checked out since they got all the fancy software and special tools. After 5 days they call me back saying they can't find anything wrong with the vehicle .
I wanna guess its a part that is probably not showing any faults and will fail in the future.
What all did they really ‘diagnose’?
With that code for low pressure after sitting for a month and half, I'd check the fuel filter, has it ever been changed?
Could also be the fuel pressure regulator...Schrader valve ought to be on top of the fuel rail, similar to the photo (325i)
No, it has never been changed, I've been thinking of changing the Fuel pump assembly which in this case contains the fuel filter inside, but I've been cautious of doing that just because the dealership might have been able to find the actual problem. BUT THEY DIDNT.
if there's no code many tech's that work at dealerships don't really know how to troubleshoot. Break it down into smaller sections...tank, pump, filter, pressure regulator, fuel rail, injectors. Find that Schrader valve on the fuel rail and verify if the pressure is indeed low and sensor is correct in reporting low pressure and then go from there.
I tried to look for the schrader valve but, its not there, my model is a 2016 328i F30 N20 engine. pressure regulator on the fuel rai, I changed that myself with original part. It no longer shows that low pressure code but, still chugging gas.
I fix a Mercedes clk months back that had something similar. Cylinder 1 fuel injector was faulty and cylinder 3 o ring was broken. It didn't throw a code or anything. Did same thing as your car.
What made you think it might be the O ring?