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Discussion Starter #1
I used cn90's vacuum method to try to find my intake leak, and I have two main questions, hopefully somebody has done this and can help me.

I have a 2002 530i with about 145,6xx-ish miles on it. Did the VANOS gaskets last year, installed brand new plugs (just checked them again by removing and cleaning them before the vacuum test.)

I bought a mechanic's stethoscope from Harbor Freight for $3.99. It seems to work really well. I ended up testing it on all sorts of things around my house...fridge, computer, etc...

Anyways, I removed the filter box, sealed the shop vac to the MAF, taped up the tailpipe and let the shop vac rip. Here's what I noticed:

1) I hear almost nothing anywhere on the rubber intake boots.
2) The intake manifold has some slight hissing noise away from the engine, which gets louder as you move towards the engine side.
3) The distribution piece (thingy on top of the manifold that splits into six little tubes, that's what RealOEM calls it,) is fairly loud too.
4) But the loudest of all comes from the tube in the photo that the silver stethoscope probe is touching. It seems to connect to a splitter and goes to a tube that goes almost straight down, and a thinner insulated tube that runs back along the intake manifold. I tried, but can't disconnect the tube here, it's pretty tight in there for my fingers.

Question #1:
I'm just not sure what the source of the leak is, although I'm fairly certain it's the tube in the photo (#4)

Question #2:
And since I tend to overthink things, :confused: Do you think the noise from the distribution piece (#3) is a separate issue. I'm confused on this as the airways are smaller, and I can't decide if it's air being pulled from the tube (#4) rushing at higher pressure due to the narrow diameter of the airways in the distribution piece, or separate leaks.

Any ideas?
Steve

The silver rod with the glare is the stethoscope probe.
 

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Looks like your having a vac leak somewhere in the CCV valve system--when one of these hoses go, you pretty much have to replace them all--where the steth is , is going to the valve itself.
 

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Just for background, why do you think you have an intake leak?

To test the CCV, let the engine idle, and remove the oil filler cap. Place you palm over the hole. You should feel a slight vacuum. The engine should not stall, but may change its sound.
If you can get access to an OBD scan tool, what is your long term fuel trim?
 

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Why don't you simply remove the entire Intake Manifold and replace every single seal and gasket as in my DIY?
On the long run it saves you alot of time to diagnose leak.
These seals are not expensive.
 

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Discussion Starter #5
Just for background, why do you think you have an intake leak?

To test the CCV, let the engine idle, and remove the oil filler cap. Place you palm over the hole. You should feel a slight vacuum. The engine should not stall, but may change its sound.
If you can get access to an OBD scan tool, what is your long term fuel trim?
Hi,

Sorry my fault, I forgot to post about the CELs. I had the codes checked, and I have
P0171
P0174
P0313
P1083
P1085

From reading other posts about this combination of codes, I'm guessing it to be an intake leak.

I also changed the pre-cat O2 sensors a few months ago, that did away with two other codes, I think P102 and P103 or something like that.
 

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Discussion Starter #6
Why don't you simply remove the entire Intake Manifold and replace every single seal and gasket as in my DIY?
On the long run it saves you alot of time to diagnose leak.
These seals are not expensive.
I'll check it out. Thanks.
 

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Discussion Starter #7
If you can get access to an OBD scan tool, what is your long term fuel trim?
I do have an OBD2 scan tool.
When in idle:
My long term fuel trim is:

Bank 1 = 5.5%
Bank 2 = 7.0%

These didn't change in the 5 minutes I scanned them.

Just for info (and I don't know if these mean anything)
Short Term Fuel Trim both Bank 1 and Bank 2 were initially around 16% - 20% with some slight fluctuations, then after about 30 seconds, both dropped to 0% over the course of 5-8 seconds, and both stayed at 0% for the remainder of the time (about 4 minutes.)
 

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I do have an OBD2 scan tool.
When in idle:
My long term fuel trim is:

Bank 1 = 5.5%
Bank 2 = 7.0%

These didn't change in the 5 minutes I scanned them.

Just for info (and I don't know if these mean anything)
Short Term Fuel Trim both Bank 1 and Bank 2 were initially around 16% - 20% with some slight fluctuations, then after about 30 seconds, both dropped to 0% over the course of 5-8 seconds, and both stayed at 0% for the remainder of the time (about 4 minutes.)
I have a Peake Tool to check codes, but what do you guys recommend to check fuel trim?
 

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Here is a list of common problems that occur with the double vanos engines and some diagnosis methods.

The idle control valve air intake boot branch gets cracks in the outer elbow accordion valleys. This can be inspected with a flashlight and mirror.

The idle control valve gets gummed up and sticks. Take it out and clean it with brake cleaner and towels.

The DISA valve is problematic on 01+ cars.
The DISA is a black box 4" high 6" wide on the side of the intake manifold adjacent to the MAF. Remove it. The flap should rotate with resistance and spring back when released. It shouldn't have any play. It breaks at its base axis. If it***8217;s broken, the flap end axis pin can be removed and the flap will fall off.
The 01+ DISA has a base gasket built into the DISA. It shrinks over time and creates a small vacuum leak. Place an 8" piece of electrical tape on a table top. Cut the tape half width with a razor knife. Place one layer of half width electrical tape over the base gasket. This will thicken the gasket and create a tight seal with the intake manifold.

The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1***8221;, the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad.
With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hole. You should hear oil bubbling in the oil pan. If you don***8217;t hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses.

The MAF sensor can be dirty and not perform well or can be failing. After market oiled air filters foul the MAF.
Take out the MAF and clean it with CRC MAF spray cleaner. Spray the MAF lightly. There are delicate wires that can be damaged. Let the MAF fully dry before reconnecting.
Cold air intake setups can drive the MAF beyond its intended operating limits and cause it to fail.
The MAF can be tested by disconnecting its electrical cable connector. If the performance problem resolves it might be the MAF. But this test can be deceiving and should be used with great care. When the MAF is disconnected the DME will err on enriching the air/fuel mix. This can easily cover up another performance problem like a vacuum leak. If the problem is unchanged after disconnecting the MAF the problem is not the MAF.
Aftermarket MAF sensors don***8217;t work.

The fuel filter gets clogged and inhibits the flow of fuel. Replace it every 60-100k miles.

Sparkplugs should be replaced every 60k miles.

Replace air filter every 15k miles.

Pre-cat O2 sensors have a lifespan of 100k miles. They have a significant effect on fuel consumption. They also affect performance. When they start degrading they cause a rich air/fuel mix. This will degrade performance some but will not cause any rough running symptoms. The main symptom is degraded fuel consumption.
The pre-cat O2 sensors are not used on cold weather cold start. The O2 sensors don***8217;t function when cold and are thus not utilized by the DME.
Aftermarket O2 sensors don***8217;t work.

Camshaft position sensors can fail and cause problems. They will usually produce a code, but they might initially malfunction without producing a code. A failing exhaust CPS will cause light performance problems. A failing intake CPS can cause significant performance problems.
Aftermarket CPS sensors don***8217;t work. OEM CPS sensors are only available through BMW. OEM CPS sensors have a BMW logo and this can be used to check if a CPS sensor is OEM.
 

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I do have an OBD2 scan tool.
When in idle:
My long term fuel trim is:

Bank 1 = 5.5%
Bank 2 = 7.0%

These didn't change in the 5 minutes I scanned them.

Just for info (and I don't know if these mean anything)
Short Term Fuel Trim both Bank 1 and Bank 2 were initially around 16% - 20% with some slight fluctuations, then after about 30 seconds, both dropped to 0% over the course of 5-8 seconds, and both stayed at 0% for the remainder of the time (about 4 minutes.)
I suspect your MAF. As stated above, try cleaning it.
I will get the flow #s at idle and WOT with my scan tool and we can compare numbers.
 

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I am doing intake gasket, ccv, vacuum hose, etc. replacement on my 2001 530. I broke the plastic tube that nyclad is referring to. It runs the length of the manifold and is wrapped in styrofoam, which dries and crumbles. Anyone know what this tube is called or have a part number? I followed cn90's diy, but I don't think his has this tube. Also looked on realoem and can't find it there.
 

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I am doing intake gasket, ccv, vacuum hose, etc. replacement on my 2001 530. I broke the plastic tube that nyclad is referring to. It runs the length of the manifold and is wrapped in styrofoam, which dries and crumbles. Anyone know what this tube is called or have a part number? I followed cn90's diy, but I don't think his has this tube. Also looked on realoem and can't find it there.
Did you check Post #16 by Max_VQ:
http://forums.bimmerforums.com/forum/showthread.php?t=1062875
 

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Yes, thanks. It's the top horizontal hose labeled as going to the intake manifold. I have a new ccv ordered, hopefully that hose will come with it. Do you know what it's called?
Thanks for your DIY, very thorough. On the M54 it's very different after you get the MAF and stuff out of the way.
 

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Oh, I think it is the return pipe, number 11617504536. Confused by the reversed diagram at oemparts. Thanks for the help.
 

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Discussion Starter #15
CCV replacement.

From the responses I get on here, and other threads I've researched, I'm moving towards replacing the CCV and the attached hoses. I'll probably order the parts this week and let you guys know how it goes.

I'm leaning towards not removing the intake manifold, just because I don't want to mess with the gaskets there. I know cn90 said it's probably a good idea to replace them, but I'm looking at doing the least amount of work possible to fix this. :snooze:

BTW...I'm in southern California, and it does get cold here at night, does anybody recommend getting the cold weather CCV or the regular one? Is there an improved replacement CCV to buy so I don't have this problem again?

Thanks!
Steve
 

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From the responses I get on here, and other threads I've researched, I'm moving towards replacing the CCV and the attached hoses. I'll probably order the parts this week and let you guys know how it goes.

I'm leaning towards not removing the intake manifold, just because I don't want to mess with the gaskets there. I know cn90 said it's probably a good idea to replace them, but I'm looking at doing the least amount of work possible to fix this. :snooze:

BTW...I'm in southern California, and it does get cold here at night, does anybody recommend getting the cold weather CCV or the regular one? Is there an improved replacement CCV to buy so I don't have this problem again?

Thanks!
Steve
HAHA cold in SoCal? I think not. You should have no reason for the Cold weather one.
 

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From the responses I get on here, and other threads I've researched, I'm moving towards replacing the CCV and the attached hoses. I'll probably order the parts this week and let you guys know how it goes.

I'm leaning towards not removing the intake manifold, just because I don't want to mess with the gaskets there. I know cn90 said it's probably a good idea to replace them, but I'm looking at doing the least amount of work possible to fix this. :snooze:

BTW...I'm in southern California, and it does get cold here at night, does anybody recommend getting the cold weather CCV or the regular one? Is there an improved replacement CCV to buy so I don't have this problem again?

Thanks!
Steve
Steve,

The reason I recommend removing the I.M. is that: at that mileage, alot of seals and gaskets will start leaking soon (search the forums!).
By doing everything all at once, it saves you so much labor later.
 

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May I ask what's cn90's method for diagnostics intake leaks? I am suspecting a leak in my 2002 530iA and would like to discard that just to focus on sensors, etc.

Thanks!
 
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