1995 BMW 540i Rough Idle Check Engine Light

Tiny
E34LIVES
  • MEMBER
  • 1995 BMW 540I
  • 4.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
Hi, I have a 1995 540i automatic with 194,600 miles

I am a bit stumped. Rough idle occurs at stop light with car in Drive (idle 600rpm), triggering a check engine light with the following fault code 1221 - O2 Sensor 2 and 1213 - Lambda Control 2. The car drives well at higher rpm, but this rough idle re-occurs after repeated resetting. Check engine light would sometimes go away after driving at higher rpm as well. Not sure if this is related, but also experiencing stalling during cold start when I engage into Drive, and requires warm up of 2 – 3 + minutes in Park before shifting into Drive without stalling.

Replaced Following Items With No Resolve:
PVC Plate & Gaskets for PVC + Throttle
Hoses Going To PVC and Throttle
Intake Manifold Gaskets
Head Cover Gasket
Mass Air Flow
Throttle Control (both of them)
Throttle Position Sensor
Engine Crank Sensor
Spark Plugs
Coils
O2 Sensor (both of them)
Idle Control Unit
Engine Temperature Sensor
Fuel Pressure Regulator
Oil Filter & Pan Gasket
Transmission Fluid Filter & Gasket
Fuel Pump Relay
Fuel Filter
Air Filter

I have cleaned throttle unit with lots of carburetor cleaner and a rag. I have checked for leaks by spraying throttle cleaner throughout engine intake areas looking for potential leaks but found none. I also put in I gallon Lacquer Cleaner to ½ tank of gas and run hard to clean out the CAT. Clean off the injector tips free of oil crud and tested with EFI electronic injector tester to make sure they were working ok. I checked coils with EFI electronic coil tester to make sure they were also working ok. I put in one bottle AT205 reseal into engine oil.

Not sure what to do or check next to address this issue, any suggestions is appreciated.

Thanks!
Saturday, March 14th, 2015 AT 8:42 AM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hi, have you performed a leak down test on each cylinder, it sounds like the engine could have a leaky intake valve which could be causing the misfire.

Let me know what you find,

Best, Ken
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Thursday, March 19th, 2015 AT 7:46 PM

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