99 328i interesting happenings ...

Hi. Got a friend who has a '99 328i. It's got an interesting problem, here's his deal. MIL lamp is lit, a scan reveals O2 Bank 1 Sensor 1 and O2 bank 2 Sensor 1. Engine idles real rough, runs fine at higher RPM.

Some history on this car - we've replaced both cam position sensors over the last 5 years, and two years ago the double VANOS assembly was rebuilt using Viton seals.

When the engine is cold, there is a popping/clunking noise coming from under the intake, by the throttle body.

He says he replaced both O2 sensors to no avail; and he also replaced the MAF sensor. I'm not familiar with these cars too much, so if someone has any ideas, please feel free to share!

Anyone?

Hi. Got a friend who has a '99 328i. It's got an interesting problem, here's his deal. MIL lamp is lit, a scan reveals O2 Bank 1 Sensor 1 and O2 bank 2 Sensor 1. Engine idles real rough, runs fine at higher RPM.

Some history on this car - we've replaced both cam position sensors over the last 5 years, and two years ago the double VANOS assembly was rebuilt using Viton seals.

When the engine is cold, there is a popping/clunking noise coming from under the intake, by the throttle body.

He says he replaced both O2 sensors to no avail; and he also replaced the MAF sensor. I'm not familiar with these cars too much, so if someone has any ideas, please feel free to share!

sure it's not a bad injector they will click when there bad.

sure it's not a bad injector they will click when there bad.

No, it's a loud noise. It sounds like someone's hitting the intake with a hammer.

i was going to say did it sound like hammer hitting metal. so now thinking your harmonic ballancer and they do make a hell of a sound.

Yeah, it's more like a hammer hitting the plastic of the intake, not metal. It's not the harmonic - the sound is under the middle of the intake on the driver side. Right where the throttle body is.