[Haich]

2004 325xi- The car has constant pending lean codes for banks 1 and 2, short term fuel trim on idle is a steady 27%, it vibrates decently at idle while in drive/ reverse, but not in park/ neutral. It has a whine that appears at a certain, fairly low cruising throttle position (both with my foot and cruise control), sounds like it's coming from the front/ center area of the car. It occasionally runs rough on cold mornings, like it's running missing a cylinder or two, and dips rpms and dies if you try to give it gas. When I fill it up with more than a bit of gas, getting the car started can be difficult- giving it gas helps keep it from dying, but it'll just stumble and die. This one will happen in phases though- it'll start happening, and then it'll be really bad, and then it'll be fine again. The car also has a weird issue where at 2200-2300 rpm and 2800-3000 rpm it'll make a kind of knocking vibration- always at these rmp ranges, and more commonly in lower gears when accelerating.

I feel like these issues are all connected- I've tried smoking/ pressure testing the intake, and I've yet to find any leaks. One thing I did notice is that if I put pressure/vacuum into the intake and then loosen the oil fill plug, the pressure will rush in/ out instantly, either to fill the vacuum or to escape the manifold. I'm not sure if this indicates that my ccv is operating normally or abnormally, as I've only seen posts about it being clogged, but as all the crankcase vents/ valves I have experience with involve a one way valve, I'm not sure whether or not this is the correct way for this one to operate.

The issues after fueling the car have also led me down the path of possibly having a faulty emissions control solenoid, but I'm not sure how to test this.

 

[Haich]

If you've exhausted leak testing and come up blank then something in the fuel system. Testing fuel pressure as Bali said is first thing to do and if low a quality brand filter is the first thing to try as it's the cheapest, then it's the pump. Injectors generally don't have much issues but if it's been left standing for long periods then getting them ultrasonically cleaned should get them working properly again.

I already threw in a filter/pressure regulator, made no difference. I'll start looking at the different fuel system tests soon. I don't think it'd be the injectors, due to misfire codes popping up on seemingly random cylinders.
I already have an obdi2 scanner app that's not obd fusion, I'll see if it'll let me make a proper recording of everything I need. Pretty sure it will. Not sure if the pump has been replaced on the car before as I've never gone and looked at it, but if it's original to the car it'll have 330k km on it.

 

[Haich]

Please describe how you are doing your smoke test, and in particular what smoke test equipment you are using.

I'm smoke testing my car by removing the maf, and hose clamping a strong rubber glove over it. I then put the hose of my fluid transfer pump into the intake through a glove finger. I suck the air out of the system first, and then I pump it back in, this time with the intake of the fluid transfer pump going through a cheap vape with pure glycol to make smoke.

 

[Haich]

Could this be a bad secondary air pump/valve?

Mine is currently failed, box of parts on the to-do list. Rough idles on startup, occasionally with misfire. Smooths out when warm. A bad EGR valve allows air to escape backward, into the SAP.

There would be corresponding codes for this P0492, P0491, ie. banks one and two, variously described depending on the scan tool.

I took mine off a while ago and blanked it. I have the euro tune on the car so I don't get codes for it. Vacuum line to the valve is disconnected.

 

[Haich]

Might be a soft failing fuel pump. Check fuel pressure at the rail, should be 50 PSI.
Have a read through this post.

• Fuel trims, lean codes, misfires, and how to diagnose

Just checked rail pressure- turning the key to pos. 2 immediately makes 50 psi, and approximately 1.5 seconds after that it drops to about 47 psi, and very slowly loses more pressure. After 10 minutes with the key out it had hit 22 psi. I'm pretty sure that this isn't quite right. I replaced the fuel pressure regulator/ fuel filter only a couple months ago as I thought it might be my issue, but maybe I got a bad unit.

 

[Haich]

OP, your initial post indicated you are getting consistent lean codes. I would focus on getting a good smoke test as the most common reasons for lean codes revolve around vacuum leaks. Like Eff, I'm not a fan of the fluid transfer pump with a cigar or vap. It's very difficult to get consistent pressure and smoke with that setup. Think about how much your time is worth. You can get a really good smoke tester on Amazon for like $80 or build one yourself for $50 (assuming you have an air compressor). Failing that, take it to a shop and pay the 1/2-1 hour of labor to get a good smoke test. Lastly don't forget (as noted by NZ) that an air leak right before the pre-cat O2 sensor cannot be found with a smoke test via the intake. Similarly a vacuum leak at the brake booster also cannot be found with a smoke test via the intake.

Good luck.

Thanks, I guess I'll try to find a shop around here that can actually do one. I called a few the other day, and they all said that "hardly anyone around here has the equipment to do it". Probably cheaper to buy one for $90 on amazon or ebay or something, or just make my own- I'm not sure what they use for the heating element, but the rest of it is just a paint can with some fittings, a tube, a universal fitting to connect to the intake, a 1 psi regulator, and some cut-down jumper cables to connect the oil heater to the battery power.

 

[Haich]

Any shop that does not have a smoke tester you should stay away from. It’s a standard required rool (among others) for diagnosis.

Well, I got the car in to a shop. No intake vacuum leaks. Maybe it's evap, but I really don't know.

 

[Haich]

Sounds like you are stuck. Try installing OBD Fusion. Read the PDF file to set it up and run the 3 standard logs. Post links to the CSV files here and we'll have a look.

The reason we like using OBD Fusion is that it gives us lots of helpful engine data without having to ask you 1,000 questions.

Got it here in my dropbox.

 

[Haich]

I've downloaded the file and had a quick play.

That's not an OBD Fusion file. My models are set up for OBD Fusion files.

While I can work with files from other apps, the structure of this file will require me to do lots and lots of manual manipulation on 8,369 rows of data. It will take too much time.

OBD Fusion is cheap. It's what we use around here for data logging. Use something else and you limit the number of people who can help you to between 0 to 2.

Sorry, I'd used the app I already had since it had data logging and said it'd export as a CSV. It had CSV 1 or 2 as options, and I chose type 1. Type 2 looks more like this when opened in excel, if this looks like it's the kind of thing that works with your program. Probably not though.