Getting bad fuel mileage.

[G1GGLEZ]

Need some help. So out of nowhere my 135i(n54) started eating gas ex: I was at 109miles 25min drive ended up at 88miles! Curious on if anyone has/had any similar problems or know what could be the issue. Thanks in advance

[ShocknAwe]

Vac leak or injector leaking

[GoRomeo]

Originally Posted by G1GGLEZ

Need some help. So out of nowhere my 135i(n54) started eating gas ex: I was at 109miles 25min drive ended up at 88miles! Curious on if anyone has/had any similar problems or know what could be the issue. Thanks in advance

Check your tires air pressure? Maybe not the culprit but a low air tire pressure will kill your MPG. Could be a factor.

[jdog006]

I recently changed injectors and my MPG has increased significantly. I didn't expect that to happen. But I can attest that bad injectors hurt fuel economy. Thinking through the reasons why that would be the case, I think that you would also see other problems (misfires, engine running rough, etc).

[G1GGLEZ]

Originally Posted by jdog006

I recently changed injectors and my MPG has increased significantly. I didn't expect that to happen. But I can attest that bad injectors hurt fuel economy. Thinking through the reasons why that would be the case, I think that you would also see other problems (misfires, engine running rough, etc).

That’s was I’m lost on I haven’t had any misfires, no rough idles, just loss in gas would I be able to possible change just the seals?

[jdog006]

Originally Posted by G1GGLEZ

That’s was I’m lost on I haven’t had any misfires, no rough idles, just loss in gas would I be able to possible change just the seals?

I assume that you could just pull the injectors and reinstall with new couplers. But I wouldn't jump to that conclusion without evidence. All of my experience has been with injectors that leak fuel internally, not externally. You should be able to find evidence of leaking fuel if fuel is indeed leaking. Gas has a pretty strong odor. I think you would smell it, if nothing else.

When I got my car back after the shop had changed injectors, I had a strong smell of gas for 50 miles or so just from the fuel that had overflowed when they changed the injectors.

[G1GGLEZ]

Originally Posted by jdog006

I assume that you could just pull the injectors and reinstall with new couplers. But I wouldn't jump to that conclusion without evidence. All of my experience has been with injectors that leak fuel internally, not externally. You should be able to find evidence of leaking fuel if fuel is indeed leaking. Gas has a pretty strong odor. I think you would smell it, if nothing else.

When I got my car back after the shop had changed injectors, I had a strong smell of gas for 50 miles or so just from the fuel that had overflowed when they changed the injectors.

Got you I ordered some coils and spark plugs, because I did get the car couple months back. Sensors are fine checked those, seen some other post of some using injector cleaner. Might give that a shot for the time being.
I did check where the injectors where and seen little puddles(red circle on image). And thanks for helping

[jdog006]

If it doesn't smell like gas, I would suspect that you are seeing oil. Either spilled from the fill cap or from a leaking valve cover. You will know if your valve cover leaks. The smoke and smell will drive you crazy.

Maybe a valve cover isn't a consumable on most engines. But I'm now on my third one with my N54. So they do need to be changed every 5 years or so.

I've never had problems with coils or plugs, except when I had a valve cover leaking oil onto them. BMW purists kind of look down their nose, but I'm running Autozone coils and they work just fine for me. I like them because they have a rubber coating the full length. All other coils seem to have just a rubber boot on the end that fuses to the plugs and becomes a nightmare preventing you from extracting the plugs down in the small plug wells.