e46 Lean Codes (227/p0188 228/p0189)

[Hill]

I'm in desperate need of help! For a while now i am receiving lean trouble codes for both banks long term fuel trim values. This is what i replaced/done already:

- A new MAF
- A new DISA
- Lower and upper intake booth
- All vacuum lines
- Throttle body gasket (also cleaned it with the ICV)
- CCV including all pipes that go with it
- Fuel filter/regulator
- Checked the valvecover gasket for leaks, found none
- Removed oil filler cap and tested it with a plastic bag, didn't get sucked in
- Tested the pre-cat oxygen sensors with INPA, seamed to be fine

The current fuel trim values:
BANK 1
Additiv (LTFT): -0.04ms
Multiplicative (STFT): +12%

BANK 2
Additiv (LTFT): -0.05ms
Multiplicative (STFT): +12%

Also while warming up, when the temp gauge reads just above the blue zone the idle sometimes jumps a bit between 1000rpm and 500rpm while idling. When the car is fully warmed up this doesn't happen anymore.

Also the shadow memory contains the following error:

52 Exhaust flap
KS --> Ground of open circuit
Error frequency : 0

I don't know if it has anything to do with the lean codes.

Does anyone know where i should look to find the problem. I'm really getting desperate here...

[bmwdirtracer]

Gee whiz: That's a whole buncha parts you threw at the thing. And a whole lot of information you sought out.

But there's no mention whatsoever of a smoke test of the intake syatem -- and THAT IS THE VERY FIRST STEP for lean codes. Without that test, and a couple of others, you should never throw parts. After the smoke test (which most likely will immediately prove the culprit), a crankcase vacuum test (NOT with a plastic bag, with a slack-tube manometer, vacuum needs to be 3-6 inches of water which would suck your bag, btw), a fuel pressure test are both needed before any parts should be thrown. Have you checked the big oil return hose into the dipstick tube? That's often a massive leak which the smoke test finds instantly.

Smoke it first!

[turbovrGTI]

id also suggest smoking it first-for your values to be that excessive youd need a large leak. Although-your values being opposites often points me towards a MAF...has the vehicle had updated programming?

[stanley]

If you do not find a intake leak, check all wiring to engine eletrical components, as there is a SB about the codes you have but for a X5 and it is a wiring harness problem. On the car it has to be replaced. Good luck!!

[thejlevie]

The apparent lack of crankcase vacuum suggests that something isn't right with the CCV. As Chris suggested a crankcase pressure check will tell for sure, but it could be that there is a leak in the CCV or hoses.

[Hill]

Guys, i already replaced the MAF AND the CCV including all hoses. So how can the CCV or the MAF be causing the problem??
The 'can be programmed counter' is 14 so i guess it has never been updated?

[bmwdirtracer]

Perhaps: or perhaps the new hose came loose. Really, please smoke test the intake/ccv system, that should have been done long before the maf and other replacements, and AFTERWARDS, to make sure no new holes had been opened up. My smoke machine has saved more customers more money than you can imagine.

[Hill]

Well gues what, my bmw dealer says to spray the vacuum lines as what they do to find a vacuum leak. They didn't have a smoke machine of any other tools to test vacuum...

Anyway, today i tested my fuel pressure and this is the result:

When i prime the car (cold) it has a fuel presure of just 44 PSI aka 3 Bar

When i start the car (cold) it had a fuel pressure between 42 PSI and 44 PSI (too low?)

When i shutdown the car it maintains fuel pressure, but rises to 48 PSI after 10 min?! After 30 minutes its still at 48 PSI, but when i start the car again it wil drop to 30 PSI for just a second or two and then rises up again to between 42 and 44 PSI.

As i recall the fuel pressure should rise if there is a vacuum leak when the engine is idling, it does not do that. Also when i give it a little gas (2500rpm) it still stays between 42 and 44 PSI

Does this mean the lean trouble codes can be caused by the fuel pump? The fuel filter that includes the pressure regulator has been replaced about 2 months ago.

[bmwdirtracer]

A fuel pressure regulator should bump pressure briefly by about 5psi whenever you suddenly take away vacuum, (i.e. by opening the throttle). I don't have the fuel pressure stats for your engine at home; but I thought I remembered 3.5 bar (51 psi). If you're truly down 1/2 a bar, that would cause lean codes, but maybe I'm just remembering incorrectly, What engine size /model is your car, and whats the production date?

I'm really heartbroken that a DEALERSHIP has no good way to test for intake leaks (smoke machine), and no good way to test crankcase vacuum (slack-tube manometer filled with water). These are such common failure issues on BMW's that such negligence, on their part, is unbelievable. I'm just a tech in a little independent on a tiny island, but I own both these tools myself, because they are indispensible. I'm sure you can find a good BMW specialist repair shop near you with these tools.

EDIT: I checked, and some cars have 3.5 bar, some have 3.0 (seems like they are some years of some Euro-market). But I wouldn't guess, if I were you. I'd check with someone who will have the specs for your car, in your market: either the BMW specialist, or the dealer. I checked a Euro-market '04 M54 325 convertible at realoem.com, but the filter/regulator does not list the psi/bar.

[Hill]

I checked RealOem and according to them i should get the fuelpump with this OEM number: 16146766942

According to this site: http://www.autocarspare.com/catalog/...146766942.html the fuel pressure should be 3.5 bar.

I looked up some none OEM replacement parts as well with the following specs:

VDO Dayton, partnr: 228-222-009-002Z, Pressure: 3.5 bar
Bosch, partnr: 0 986 580 132, Pressure: 3.5 bar
Pierenburg, partnr: 7.50062.50.0, Pressure: 3.5 bar

I'm guessing i'm going to be needing a new fuelpump then...

[Hill]

Checked the voltage as well today: it spikes to 11.9v. Seems to be the same when i directly read it of the battery with ignition turned on (including exterior and interior lights on).
The other 2 wires read around 5v constantly, is this good??

[erik2003]

please let me know what you find i have the same exact fuel trims, i replaced all parts you mention and all known tests have passed. you

[erik2003]

Im waiting in a battery and both pre cat o2 sensors(as they failed tests). check battery and replace if needed, check exaust for leaks, remove secondary air valve and bench test. let me know what you find

[bmwdirtracer]

Checked the voltage as well today: it spikes to 11.9v. Seems to be the same when i directly read it of the battery with ignition turned on (including exterior and interior lights on).
The other 2 wires read around 5v constantly, is this good??

Well. hell, let's deal with problem 1, first: Your battery is at about 10%. You need to be reading 12.6+ at the battery, and at least 12.5 at the pump. Let's start there.

Second: don't go ordering a fuel pump , this is almost certainly that you have the wrong fuel pressure regulator, or a bad one.

The pump will give about 100 psi, if you pinch off the return line. The REGULATOR (which is built into your fuel filter) is what determines how much fuel is returned to the tank, and therefore how much pressure is retained in the fuel rail.

Or, your guage was reading incorrectly. But the lean mixtures plus those guage readings on a 3.5 bar car would have me replacing the regulator/filter.

[Hill]

I replaced the filter with pressure regulator 2 months ago with a new Mahle KL 149. It states that it's an OEM part and it's for an E46 325 i/xi/ci (01-05) or 330 i/xi/ci (01-05).

When i replaced it, i reset the adaptation values, but after a day they were pretty much the same as before...

When i read the battery with the ignition off, its about 12.6v

[Hill]

Im waiting in a battery and both pre cat o2 sensors(as they failed tests). check battery and replace if needed, check exaust for leaks, remove secondary air valve and bench test. let me know what you find

The secondary air valve is also new, don't have any exhaust leaks. I'm really believing it's the fuel pump, since the pressure is to low and i recently changed the filter/pressure regulator with a new one...

[bmwdirtracer]

Do you have rubber hose joining your filter inlets/outlets to the fuel lines, or just hard plastic quick connects? If you have rubber, pinch the return line while someone watches fuel pressure. If the pressure shoots up to 75 or 100 psi, the pump is likely just fine.

[Hill]

Well i bought a new fuelpump and put it in. Gues what! It reads 3.5 bar!! Instantly i reset all my adaptation values and took it for a drive, i hope the lean codes are history now. I will post my fuel trim values in a couple of days.

[erik2003]

e46 faulty pumps are the norm lately for lean multiplicative mixtures(9-12%) if you check pressures at idle you may missed it but under full load you will feel the hesitation/surging and fuel pressure dropping to 30 PSI. Diagnosing between filter and EKP pump is current ramping the pump with DSO you can see the comutator failure. After I replaced my faulty pump multiplicative drop to 3% after 10 miles

[Hill]

Well i'm glad things finally sorted out. I've been at it since september last year... Made a total cost of €1235,- on parts, some completely unnecessary.

There is a valuable lesson to be learned here, first MEASURE/DIAGNOSE in stead of blindly buying parts to fix the problem like i did... it can save you a lot of money. On the other hand i won't have to worry that the next 200.000km will be a problem since i replaced most parts that usualy break down and cause problems. I will try to write a 'fuel trim diagnose/repair plan' to help everyone fix and diagnose these problems with the fuel trims and vacuum problems.