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Discussion Starter #1
Hey all,

This would be my second post on this issue as I have wandered through countless posts with no avail in reaching a solution


My car is a 2004 325 with 101,xxx miles on it

General description of the problem:
- Whistling noise on acceleration, varies with throttle, most noise between 2000 and ~4500 rpm
- Service engine light has gone on
- Have checked that DISA + MAF sensor are plugged in, they are
- MAF looks perfectly clean, possibly even replaced by previous owner, but have not attempted using MAF cleaner on it
- **** Bouncing idle ****
- Lower (thinner) vacuum hose to F-piece on upper intake boot is not present (previous owner was an idiot?)
- Have already replaced lower intake boot
- Upper intake boot has cracks that do not go all the way through (tested also with smoker, no leaks)
- I notice some gunk built up around the seal of the DISA valve:bump::bump:
- Noise began almost immediately after installing CAI, service engine light went on ~1 week after installing the CAI




Could anyone diagnose this problem? The whistling is incredibly annoying and the rough bouncing idle is worrying me :/ ANY help would be greatly appreciated.

Cheers! :thumbsup:
 

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Discussion Starter #3
Thanks for the reply man. I doubted the CAI was the problem too; I assumed greater air flow = problems in this area becoming much more obvious (noises especially). I will be getting an OBD reader soon, will either get back to you via PM or update this thread. Appreciate the help!
 

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Thanks for the reply man. I doubted the CAI was the problem too; I assumed greater air flow = problems in this area becoming much more obvious (noises especially). I will be getting an OBD reader soon, will either get back to you via PM or update this thread. Appreciate the help!
Smart phone App and interface for $35 or less is a wise way to go.

In the short term, borrow an OBDII tool from the auto parts store. At least you can get a jump start on the issue.
 

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Cai is the cause of the whistling and perhaps occasional hiccups in idling. Your valve cover gasket is leaking and your spark plugs or a couple of them drenched in oil
 

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BEFORE YOU LIFT ANOTHER WRENCH, why don't you pull codes so you have a clue which bolt to put the wrench onto?

You said you installed a cold air injection, so odds are very high that this is where the train jumped the rails. You likely have caused an intake leak -- vacuum leak -- that is setting a lean code, P0171 & P0174. But, there is no way to know what the cr is mad at you about UNTIL you pull codes.
 

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Discussion Starter #7 (Edited)
okay, after a weekend camping, i'm back working on my car.

Update:
- SES light is still on
- Replaced DISA O-RING, inspected entire DISA assembly, no problems
- Whistling has subsided slightly, but still very noticable
- Rough idle is GONE, throttle is more responsive
- Forgot to add this: I replaced the sparkplugs a few days ago with OEM Bosch Platinum 2+


FAULT CODES:


P1512
P0111
P0071
P0102
P0128

Any help would be greatly appreciated

Cheers!
 

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okay, after a weekend camping, i'm back working on my car.

Update:
- SES light is still on
- Replaced DISA O-RING, inspected entire DISA assembly, no problems
- Whistling has subsided slightly, but still very noticable
- Rough idle is GONE, throttle is more responsive
- Forgot to add this: I replaced the sparkplugs a few days ago with OEM Bosch Platinum 2+


FAULT CODES:


P1512
P0111
P0071
P0102
P0128

Any help would be greatly appreciated

Cheers!
Google is your friend.

P0128 - Probably need a thermostat, see 3rd link in my signature.

Get Freeze Frame info, log data and mileage, clear codes, see what ones pop first again.

Need to see Fuel Trim info as well.
 

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Diagnosis: almost positive it's a vacuum leak. It also could be an exhaust leak.
Location: intake elbow, intake manifold gasket, exhaust manifold gasket or pre cat exhaust leak.
The accordion style intake boot that comes with these cars is prone to cracking. That would be the first place to look. Pull apart the folds of the boot and you'll probably notice tears. Replace the boot with a silicone (smooth) boot from an aftermarket vendor like ecs or turner, or get an oem accordion style if that's what you prefer. If it's not a vacuum leak, then you're experiencing an exhaust leak. Which will give you almost identical symptoms (whistling and lean codes). With a vacuum leak or exhaust leak, the o2 sensors are reading more air than normal at the given rpm and fuel delivery. The dme will compensate for this and adjust your fuel trim to try and even out the air/fuel ratio. Once it realizes that it can't, it throws a lean code and illuminates the ses light.
First check your intake boot, then check your exhaust manifold. Listening to the engine while feeling for suction will help you pinpoint the location of the leak. Then if all else fails, pull the intake manifold off and examine the manifold gasket.
Good luck and let us know what you find

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Discussion Starter #10 (Edited)
Sorry for being so slow with my updates, i've been very busy lately. So I was able to clear all of my codes except P0071. This corresponds to the ambient air temp sensor, which I don't even think is faulty -- as my AC works perfectly fine and the temperature is accurate (compared with what's listed for the weather). My whistling continues, I have the hunch that it is an exhaust leak. Would P0071 really be causing the SES light? Seems weird to me. I've attached my fuel trim data per Torque, not sure if this is what you were looking for. Also, I noticed my oil light goes on yellow at times during driving but usually just after the car starts rolling; and it only goes on for ~10 seconds. May this be related? To reiterate, on the upper intake boot where there is an "F" connector, only the top, larger vacuum hose is connected, and the smaller, lower vacuum hose is no where to be found. It isn't even found on the opposite side of the car where (I believe) it should be connected with the butterfly valve in the exhaust. I really want to get rid of this dumb noise, as it's keeping me from doing tons more to this car. Thanks for reading.


Fuel trim data



Please post if you have any input on the aforementioned issues

- illuminated
 

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The smaller hose on the F connecter connects to a hard line back on the drivers side firewall that runs vertically under the drivers floor and connects to the fuel pressure regulator.

NOTE, this hose is nothing more than a vent line in case the fuel pressure regulator diaphragm fails and/or keeps a clean, unobstructed, atmospheric air on the opposite side of the fuel pressure regulator. Do not let anyone tell you anything differently. The fuel pressure regulator is not vacuum controlled in the later cars with the combo fuel filter/fuel pressure regulator which you have unless for some reason you have a SULEV vehicle.

You oil light is coming on either due to the oil level sensor starting to fail or the engine is a bit low on oil. You could add 1/2 quart of oil and see if the yellow oil light goes away.

The Fuel Trims are a bit high, not high enough in the screen shot to trigger Lean codes at this time. The 99% Fuel Trim values are likely not the correctly values. There are multiple Fuel Trim values that Torque displays and I do not think the 99% values are correct.

Likely you have a vacuum leak you have failed to located.

Short story here - https://www.youtube.com/watch?v=zMok2y05jNE

Or you can look at other things on the search and make yourself a test tool.

Need to reread the 1st link in my signature, covers all the common E46 issues.
 

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Discussion Starter #12
wait so, the fact that the lower smaller hose isnt present on the F connector...doesnt matter?

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wait so, the fact that the lower smaller hose isnt present on the F connector...doesnt matter?
Yes and no.

Yes if the F connector is not capped off. No, if the F connector is capped off and the port side of the fuel pressure regulator is open to atmosphere.

The hose is to port raw fuel into the intake path if the diaphragm fails, it will not leak fuel on the ground. Maybe less likely to be a fire hazard, but this I am not sure of if raw fuel in being fed into the intake path before the throttle body. Might cause the engine to stall out?

Ideally you should find the hard line along the firewall hear the brake booster, reconnect the line to the F connecter as designed and repair anything that is cracked, broken or leaking.

You also have a 325xi and FYI, the 325 does not have an exhaust butterfly, only the 330's from my understanding.
 

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my car most certainly has the butterfly valve, i can see it.
Like I said, my understanding was only the 330 had the butterfly, but as usual I could be wrong. As I recall most of the early 325 did not have the valve, maybe the XI have them, maybe they added this on the facelift cars?? I am sure one of the experts can chime in here about the history on the muffler flap!

Here is the deal on the butterfly valve in the rear muffler.

1. The valve should be open when the car it turned off, if it is closed when the car it turned off, there is a problem with the valve being stuck and it needs to be opened up. You may have a BUNCH of carbon built up inside the muffler. This can kill performance and needs to be address if the valve is stuck closed.

2. If the valve is open when the car is off and closed with the engine running, then this kind of implies the vacuum to the valve is working and things are operating as expected.

3. If the valve is open when the car is off and when it is running, this means either the valve is stuck open, someone has done the golf "T" mod on the car or there is a problem with vacuum source/line to the valve.

Anyway, not sure what to tell you about the mystery whistle, you need to address this as ANYONE from the Internet is really a guess.

Fuel trims are a bit high, you have at least 1 vacuum hose missing in action, unclear if the F connector is capped of at this time. Freeze Frame info will be helpful once the CES/SES/MIL comes on again.
 
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