BenzWorld Junior Member
Date registered: Feb 2004
Mentioned: 0 Post(s)
Quoted: 3 Post(s)
400E smog problems
Hi MBZ gurus,
I have 93 400E with ~133K miles on it. I am unable to register it as it fails smog. I had it smogged when I bought it and it came up as a gross polluter, my mechanic replaced the O2 sensor, had it smogged at some one he knew and it passed with flying colors. But when I took it to a test only station it failed again. I was told to drive around for a couple of months and try again, I had it tested again and it failed again with numbers bordering on GP again! (I made sure the car was running hot). The NO and HC numbers were really high. The interesting thing is that it runs clean below 15 MPH ( and passes the 0-15 MPH test)but goes crazy as soon as you hit 25 MPH (fails the 25 MPH test).
My mechanic has no clue as to what is wrong, he says all the codes come out good, the fuel pressure is OK, the O2 sensor is OK, the catalytic converter is OK.
This is driving me nuts, my mechanic can't fix it, I can't register the car, and I do not know if a different mechanic would help.
I would appreciate any insights into this.