1995 540i fouled plug
 

My problem is - the rear spark plug on the lefthand bank is fouling. I changed all the plugs and replaced the ignition coil on the cylinder with the fouled plug. Also changed the driver side O2 sensor. Fault codes were 1222 before the O2 sensor change and 1212 after the O2 sensor change. I get a lot of smoke at startup and idle. I evidently have a 7 cylinder 540.

Compression check as follows:

Left bank, front to rear = 200, 200, 202, 222

Right bank, front to rear = 200, 210, 204, 212

Engine was up to temp when I did the compression check, throttle was side open, cycled each cylinder thru 12 revolutions.

Any suggestion as to what I should be looking for?

Tom

Turns out the problem was with the DME - a defective relay that fires the #8 plug. Diagnosed and repaired by ecudoctors.com located in Florida. I sent the DME to them, it was repaired and returned within a week - $475 - expensive, but cheaper than a new DME - hope the repair keeps working.

Tom