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Discussion Starter #1
Greetings Everyone,

I've been dealing with a persistent oxygen sensor adaptation limit error on my 2003 325i. Having read numerous posts I see I need to do a smoke test to find the intake leaks that are triggering this error.

I have access to a good smoke machine, but I need to learn how to use it on the 325.

Could those of you how do know, offer any suggestions or links?

Thanks,

Juan Ochoa
Harvard, MA
 

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Smoke works for some things, however, I find that a better way is to get a cheap can of brake cleaner, the cheaper the better, and us that to spray around the intake and hoses at an idle. Your idle will usually smooth out and increase in RPM when you find a vacuum leak.

Make sure you use some sort of fender cover to keep the brake cleaner off the paint and it would be a good idea to remove the main plastic top engine cover to protect it from the brake cleaner as well.

Another option is propane, get a propane torch and use some vacuum hose to adapt the torch to allow you to put the vacuum hose in areas to test for vacuum leaks. But keep the torch upright so you do not dump liquid. Propane can be a bit more difficult and dangerous to use as well.

I have found unusual intake gasket leaks and other problems that a smoke test would not have located using the brake cleaner method. I find this method to be much more sensitive than smoke testing.

YMMV
 

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On the other hand, I was NOT able to find this moderate leak in my lower intake boot by using the brake cleaner trick - I had to disassemble to find it. A smoke test might have worked, not sure. (in retrospect, the propane might have worked too).



 

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I hear you on the intake boot crack, the problem is with the crack on the bottom it is hard to hit that spot directly with any kind of spray, however, that is such a well known problem, I would probably just replace the elbow at 4 years just to eliminate the problem.

How old are the boots when folks are typically seeing them fail?

I think age is more of an issue than miles with this type of thing. Also climate may play into the failure a bit.
 

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The crack on the intake boot is so common and usually REALLY easy to feel. It would be the first place I'd check. I had the exact same problem before. After that the spray test should work well.
 

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Discussion Starter #6
Thanks so much for the ideas and help.

When it is not raining and the engine is cool, I'll poke around and check for the boot problem. This winter, when it was really cold, the engine would whistle at certain throttle settings. Cracks this big would certainly do it.

Juan
Harvard, MA
 

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What a nice clean pics. What a camira R U using. it's really helpfull.
Thanks
 

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But I have Q.
Is it necessary to change the sealing every time you remove the DISA?
 

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Intake boot cracks are a common source of intake vacume leaks as these rubber parts age. Another problem with these particuliar codes is that you may need to reprogram your DME to the newest software. Indy or Dealerships can do this for a small fee...$75 at indy shop.
 

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pull out the brake booster vacuum line from the booster, insert smoke probe in the hose. thats it.
Mind giving bit more info on this?

Basically here's whats going on
I just got "P0171 and P0174" Codes via Hand held Reader and "SAE Code P0189|BMW-Specific Code 228|Description Fuel Trim Bank 2, O2 Control Adaptation Limit" via CarSoft and based on the research it looks like I either might have:

a) Vacuum leak
b) Dirty MAF
c) O2 sensors about to go and not responding quickly enough but still good not to throw CEL (car has 90k miles)

I am really pointing to vacuum leak as I have small idle issue (when coming to stop, once in a while idle drops to 500, the goes up, then bit down, then it finally settles). My car is supercharged

I've found the shop that will smoke test my car but I want to make sure it's done right. I believe there are two tests that can be done. Obviously one test to smoke my intake and 2nd to test crankcase, correct?

So my questions are:
1) To test intake for leaks, hook up smoke machine to intake hose that goes SC unit?
2) To test crankcase, hook up smoke machine to top of dipstick tube?
 
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