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BMW 120D E87 2007
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Discussion Starter · #1 ·
My bmw 120D exhaust is hitting the bumper hard when I move off in gears 1 and 2 (1500 to 2000 rpm) . When accelerating there is a heavy vibration sound coming from the engine. Feels like there is a loss of power because of such vibrations. Has been gradually getting worse. Engine is vibrating excessively when looking at it at idle. I've been trying to resolve this for the last 4 months and have thrown a lot of time and money into trying to resolve this with no luck. I've been to many garages but they suggest I replace components I had already changed in the last 4 months trying to resolve this issue. Here are the things i've already done trying to resolve this with no luck:

-Engine and transmission mounts
-Oil, oil filter, air filter change
-Clutch and flywheel
-Crank shaft pulley vibration dampener
-Both prop shaft couplers
-Aftermarket exhaust realigned with new rubbers, flex pipe, plenty of clearance
-Engine mounts AGAIN (thinking the initial ones were defective)
-All glow plugs and glow plug module
-Injectors deep cleaned and reseated with new copper washers and O-ring
-Air inlet manifold gasket
-Engine mounts for the 3rd time as they had already worn out due to high vibrations

-INPA diagnostics:
Error codes: 4B1C,4DFF,4E09 ( fuel heater will be replaced later, had swirl flaps deleted)
engine roughness: all cylinders in limits, all rpm constant,
sensor values look ok but not too sure what to look for here to diagnose the engine vibrations.
I spent countless hours and over £2k trying to resolve this. Holding onto a car for sentimental value, but I'm afraid I might have to let it go if I'm unable to resolve or burn more money on this. Car still drives and economy is as usual but feel like it can fail at any time. The vibrations, shaking and banging bumper is driving me insane. Please help me, I tried what i can and feel defeated

I appreciate the time and effort to help me, thank you.

current engine mods: BMW 120D, E87 2007, 155000miles
  • Stage 1 remap (220hp, 420nm)
  • EGR, swirl flap delete
  • DPF back straight pipe (2.5”)

54 Posts
I can't offer a definitive solution but the 4B1C error does appear to have caused owners some head scratching. Googling around, this appears to have put vehicles into low power mode (rather than limp mode), the error has not always been cleared by replacing the heater due to other causes such as broken wires in the heater connector. I'm also seeing that people have suffered severe battery drain due to faulty heaters that remained permanently on and were subject to a limited recall.
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