M30 Running Too Rich and Misfiring

[AsharC]

Hey,

My e28 is running really rich and I can't get figure out why. It also misfires under load, it won't at idle. Runs rich at idle but no misfire.

Parts I've replaced:
Ignition Coil
Spark Plugs
Distributor Cap and Rotor
Spark Plug Wires
Fuel Injectors
In-tank fuel pump
Fuel filter
Coolant Temp Sensor
Replaced the crank sensors
Tried a different ECU
Tried different AFM's with no luck

Any help is appreciated.

Thanks
Ashar

[ahlem]

What's your compression numbers?

[AsharC]

Haven't done a compression test yet.

[AndrewBird]

O2 sensor. When they go bad, the car will run rich.

[AsharC]

Unplugged it, made the car run a little more rich.

[1craze30]

535, 533, 528? Euro, or American? What engine number? B32, 34, 35? All have different engine systems, although very similar.

[AsharC]

85 535i, M30B34, American.

[1craze30]

Have you also checked te coolant temp switch? Not sensor. It's the two prong guy next to te cts. A good way to check temp switch is to jump te connectors and if idle changes and smoothes out you know what to replace. Just a free check to see if it's bad.

Also check for vac leaks around the intake tract, those rubber pieces may not show signs of being cracked, but once warm, can begin to cause all kinda of vac leaks.

[1craze30]

Any update? You get this sorted out?

[AsharC]

Any update? You get this sorted out?

Yup, I swapped out the ecu with an edu out of my parts car and it runs well. Still a tad bit rich, but nothing serious.

[george graves]

Does it run rich after warmed up? My M30 runs pig rich at warm up - so much so, you can smell it. I think my cat is worn out, and maybe the OCV valve need a cleaning. But still pulls strong that I don't wan to mess with things right now.

My guess for you would be the o2 sensor. It will go open loop, and just spit fuel in.