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Old 01-18-2013, 03:31 PM   #3
Registered User
Join Date: Jan 2012
Location: Nashville, Tennessee
Posts: 2,106
My Ride: 2002 330ci
My SAP may have been bad for a long time and I not know it because i dont know what its supposed to sound like. I know ive never heard any distinct noises from that area while under the hood ever.

The SAP sends fresh air to warm up the cats....also sends fresh air to help burn the rich fuel when cold starting. This is where i could think they are related.

Did running rich for a long period of time on cold starts carbon foul the o2 sensor.....which is past its replacement date anyway. only speculating here.

my thoughts on this are that one or both of my precat o2 sensors are bad and went bad over time due to lack of SAP and wear and tear.

i would like a diagram or picture of which connectors go to all 4 o2 sensors just to make sure they are in the right spots. i believe they are but i want to be sure. Who knows who worked on this thing before i owned it. Whoever it was neglected it and ive had to sort all kinds of stuff out.

It could be the MAF....i found an app to measure MAF in g/sec. havent done this yet.

Last edited by glhx; 01-18-2013 at 03:57 PM.
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