95 318i Emission Lambda Control issues
I have a 95 318i 1.8L 4 cyl. w 211 k miles. I recently experienced real bad idle issues surging up and down. Gets better after warm up but still bad. Fuel economy is gone. It is blowing black smoke out of exhaust. (Running Rich) It first happened intermittently when I would surge acceleration, it would run rough at idle but then it would go back to normal. I noticed a decrease in MPG. So I kept track and was getting only 17 MPG (Normal 25+). Upon initial error code reading got a 2A(Knock sensor) 46 (o2 sensor) 49 (Vehicle speed signal not present). I have replaced all these items and codes are clear on these. The final code I am getting is a C9 (Emission lambda control) error from my R5 code reader. I have replaced the O2 sensor, Water temp sensor, Fuel pressure regulator valve,vehicle speed sensor(in differential), new rubber boot from MAF sensor to throttle intake, new Knock sensor 3-4 cyl. I have removed and cleaned ICV(idle control valve) i can hear it run when car is on) I checked Throttle positioning sensor (Electric) perfect reading. Removed upper intake and checked all hoses for air leaks, NONE FOUND. Cleaned the throttle body, upper intake, MAF sensor.Check ECM, (clean contacts/no water) PLEASE SOMEONE HELP !!! I AM AT MY WITS END AND MY WALLET HURTS EVERYTIME I GO TO THE FUEL PUMPS. Quick question ?? Could the Catalytic Converter be causing this? I noticed code reader for my car model does not have a code for a "Bad CAT" Anything is appreciated.
PS. Recent repairs, New Fuel pump, fuel filter, alternator, crankcase ventilation valve & hose
Last edited by iamdonjuan; 10-04-2012 at 11:22 AM.
Reason: forgot to add recent repairs