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Old 12-21-2010, 07:59 PM   #17
Registered User
Join Date: Feb 2010
Location: Virginia
Posts: 28
My Ride: 2001 325i
Originally Posted by xi_ter View Post
Great DIY for a non-working secondary air pump. Under the CPO warranty I had my Secondary Air pump replaced, but continued to throw CEL codes due to low secondary air flow.
If the pump is working, and making the leaf blower sound for 2 minutes after a cold start, use the secondary air pump to blow Seafoam into the exhaust ports and valves. This will clear the secondary air passages enough in the engine to allow the second O2 sensor to detect a higher secondary air flow.

Then let the engine sit 15 minutes and warm up the car. There will be significant amounts of Seafoam carbon burnoff in the form of white smoke. The carbon burnoff will clean exhaust areas in the path to the O2 sensors that measure secondary air flow.
xi_ter and all,

This DIY is very helpful. I am trying to track a problem. Symptoms are intermittent rough idle, sometimes at start, sometimes not - also happens under any kind of stress, i.e. going up a hill, etc. Once it starts running rough, it won't clear itself until car is turned off and restarted. I was thinking vacuum leak so replaced ccv and hoses. One hose had hole and leaking oil, so that was worth the effort but did not fix problem.

I tried the Seafoam procedure just as you explained and I noticed that the fluid is not emptying from hose. I connected back up and let it idle for 12-15 mins. and still in hose. Drove for about 15 mins. (still running rough) checked again when I returned and still full of the Seafoam fluid. No white smoke at idle or while driving.

Would this seem to indicate bad or clogged SAP?

I took it to dealer out of desperation because I need to get to work and back and it's been too cold to spend much time on it. Dealer said something like low pressure on lifters causing misfire on all cylinders. Said that the cam needs to be pulled and rebuilt with new lifters and other stuff... whopping cost of *$5,200*. Car runs really well when it's running, but I think that the computer is compensating for a too lean or rich condition.

I am going to invest in the Peake code reader, but that will have to wait until after Christmas this year. Thanks in advance for any help...

BTW, the mechanic at the stealership was nice enough to offer me $1,000 to take the car off my hands. Once I fix this problem I'm going to register a complaint to BMW of America, but I need to find and fix the problem first.

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