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Discussion Starter · #1 ·
02 745li

I have been trying to diagnose obd error "minor vacuum leak" for a while. I have been looking for the leak but can't find it.

At the suggestion of some e38 owners, I removed the oil dipstick with the car running - all of a sudden the idle dropped and almost stalled. They say this is a failed OSV for the e38 but does the e65 have one and is it my issue?
 

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Discussion Starter · #2 ·
The OBD errors I am getting are:
Too rich at idle P2187 and P2188 (both piston banks)
P0442 evaporative system emission leak (small)

These two are most likely related. But are they caused by the vacuum in the oil dipstick?
 

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I'm not sure what an OSV is but there have been issues on the E65/E66 with the Crancase Ventilation Valves with similar symptoms.
 

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Discussion Starter · #4 ·
OSV = oil separator valve.

I have replaced my crankcase vent valves a while ago. They were broken at that time, but they did not fix the problem.
 

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A little vacumn is normal. This is part of the emissions related to crankcase ventilation
 

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Discussion Starter · #9 ·
If you didn't check the dipstick with the car running how would you know if there should be vacuum.

I'm not checking my oil cheif, I'm diagnosing my car. Notice the difference?
 

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A little vacumn is normal. This is part of the emissions related to crankcase ventilation
This makes allot of sense, because I had this done when they changed the tranny! They didn't charge me anything at the dealership this morning - maybe they expected that the car would react to a small vaccum leak. I was kindda shocked actually!
 

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Discussion Starter · #13 ·
Comments based on nothing but heresay do not help and may lead to a wrong diagnosis thus I feel that anyone should question such things.

Anyways, I bought a mityvac to check things out. I'm going to read the vacuum in the dipstick and try to find a leak if any.

Also, I will take out the maf and clean it to see if that helps.
 

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Comments based on nothing but heresay do not help and may lead to a wrong diagnosis thus I feel that anyone should question such things.

Anyways, I bought a mityvac to check things out. I'm going to read the vacuum in the dipstick and try to find a leak if any.

Also, I will take out the maf and clean it to see if that helps.
Let's us know what u find!
 

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Discussion Starter · #15 ·
Ok so I've done lots of things.

The good thing about my findings is that they will apply for many cars not just e65 but also E60 545i 550i, as well as to a lesser extent e39 540i.

I have replaced/repaired many of the Vac lines in the engine bay. Some of the smaller 1/4" line crumbled in my hands (100k miles).
There has clearly been issues with my CCV system since I see coolant and oil throughout the vent pipes (likely due to the purge control valves I replaced months ago). Note that With the replacement of the PCVs, i corrected a stalling issue with the car, but the idle was not perfect.

I replaced this pipe:
http://www.realoem.com/bmw/showparts.do?model=GN63&mospid=47785&btnr=11_3259&hg=11&fg=15
item #1
with my own tubing 3/4" heater hose and fittigs. I don't like BMWs pipe. It is made of hard 'shrink fit' plastic that cannot be disconnected. Furthermore the seals are only provided by o-rings. There is no pressure holding this pipe to the engine, thus making it prone to leaking if the O-rings wear out.

Furthermore, I found the VAC PUMP connector (going to the fuel tank I believe) to be leaking (there was oil in and around it). I replaced this with 2" of 1/2" heater hose and hose clamps.
Lastly, I found that the evaporative emissions solenoid valve (that allows the fuel tank vapors to be vented into the throttle body) was leaking! I replaced the connectors, which were probably leaking, but the valve body itself was leaking. Again, stupid BMW design: the valve is litterally made of two hard pieces of plastic clamped together. Not sure why BMW thought that would seal properly. Anyways I used some automotive goop to go around the valve body and seal it up.

My analysis:
I have resent engine lights. I need to let the car do its thing to check the OBD system. However I believe that I will have fixed my engine codes in the following ways
1. Too rich at idle P2187 and P2188 - these were probably caused by the leaks in the PCV system - maybe too much oil coming in, or maybe air coming in.. either way, I believe these have been treated.
2. P0442 evaporative system emission leak (small) - this was most likely due to the leaking evaporative emissions valve that i repaired with the goop.

Ill check back in a few days to see if the light stays out.

Cheers
 

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Discussion Starter · #16 ·
Oh I should also mention that my idle is ROCK SOLID now. NO fluctuation whatsoever.

This is a very objective observation. I am an engineer by trade and I am keen on precision, and I can say that my idle is now precisely constant with the aforementioned fixes.

I highly recommend anyone with aging air hoses to go into their engine bay and replace crusty ones. You will be pleasantly surprised.
 

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Discussion Starter · #17 ·
Okay so OBD did its rediness checks. As I suspected, Errors P2187 P2188 P0442 are all gone.

however there is a new error now (Wtf): p0430 catalyst system efficiency below threshold.
Never had this error before. Why is it coming up now?? Why not before?? argh
 

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Sounds like the O2 sensor thinks your catalytic converter isn't doing it's job. Check your oxygen sensor wiring and/or change it out. If that doesn't work, your cat is probably bad. With all of the work you did, look hard at the wiring/connector. You might have knocked something loose.

Best,

-Mike
 

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Okay so OBD did its rediness checks. As I suspected, Errors P2187 P2188 P0442 are all gone.

however there is a new error now (Wtf): p0430 catalyst system efficiency below threshold.
Never had this error before. Why is it coming up now?? Why not before?? argh
now that the car's idle is corrected an no longer running rich the O2 sensors can measure efficiency properly. Usually when the car is running to rich and the car can't trim the fuel to fix it without detonation it "throws out" the reading after the cat until the previous issue is fixed.

the problem is that when cars run rich, the cat's get soaked in fuel and if the car isn't running properly it can damage them or the O2 sensor. The best thing to do is go to an emissions place and see if they can do the tailpipe sniffer test and see if the car is above what it should be. If it is, it's the catalyst failing. If not, then it's the O2 sensor.
 

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Discussion Starter · #20 ·
now that the car's idle is corrected an no longer running rich the O2 sensors can measure efficiency properly. Usually when the car is running to rich and the car can't trim the fuel to fix it without detonation it "throws out" the reading after the cat until the previous issue is fixed.

the problem is that when cars run rich, the cat's get soaked in fuel and if the car isn't running properly it can damage them or the O2 sensor. The best thing to do is go to an emissions place and see if they can do the tailpipe sniffer test and see if the car is above what it should be. If it is, it's the catalyst failing. If not, then it's the O2 sensor.
This makes perfect sense. In fact, I said it to myself: "maybe now that the other 3 errors are clear, the car can finally get to the rest of the tests"

What I will do is swap the bank1 and bank2 sensors. If the error travels with the sensor then it will be replaced. If the error persists on the same bank, then I will get an oxygen sensor de-fouler/minicat: http://www.bigdaddiesgarage.com/
 
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