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Z3's 3.0L and 2.8L
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when engine is warmed up both of the STFT drops closer to 0 and both LTFT rises past 15. also noticed when i rapidly increased rpm the STFT dropped to -20 for a quick second and returned to normal.
Anytime at hot idle, if the total fuel trim (STFT + LTFT for that bank) settles above 10%, it is indicative of a vacuum leak. Yours is around 15%.

To confirm if it's a vacuum leak, you rise the rev's and watch the STFT. If it drops, might even go negative, then this confirms that you have a vacuum leak.

Your notes above are doing this test.

What is happening? The unmetered air has more impact on the fuel trims at idle than at rev's because the ratio of unmetered air to metered air is greatest at idle. The fuel trims go rich (negative) when reving because that is how the engine works. It adds more fuel to support the increase in load.

Good luck with the smoke test and repairs.
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #26 ·
The second video confirms adapted lean condition, so smoke test and leak fixing is the next step. 馃憤
Anytime at hot idle, if the total fuel trim (STFT + LTFT for that bank) settles above 10%, it is indicative of a vacuum leak. Yours is around 15%.

To confirm if it's a vacuum leak, you rise the rev's and watch the STFT. If it drops, might even go negative, then this confirms that you have a vacuum leak.

Your notes above are doing this test.

What is happening? The unmetered air has more impact on the fuel trims at idle than at rev's because the ratio of unmetered air to metered air is greatest at idle. The fuel trims go rich (negative) when reving because that is how the engine works. It adds more fuel to support the increase in load.

Good luck with the smoke test and repairs.
i linked some videos above with a better obd scanner and it shows the maf sensor functioning in kg/h

doing the smoke test now. thank you for your help so far 馃憤
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #27 ·
Your Scanner is showing the pre-cat O2's as mA values around zero mA. Both are cycling correctly.

Even though the engine was not up to full operating temp, the total fuel trims (STFT + LTFT) for both banks are showing around 20%. This indicated a problem.

The MAF value was in pounds/minute and not grams/second, so I have no idea if the MAF value is correct. Your 325CI should be drawing around 2.9 to 3.4 g/s at hot idle.

Read your first post again.
Whenever you clear the codes, it clears the monitors as well.

Running the required drive cycle usually brings the monitors back into "ready".

Suggested next step is to smoke test the engine and find the vacuum leaks that are causing the total fuel trims to be around 20%. Read: How to Smoke Test
when i did the scan with a different obd scanner the 鈥渕ass air flow鈥 value was around 11.3 kg/h
i鈥檓 wondering if this maf value is correct?
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #29 ·
Yes, it's about 3 g/s
Automotive tire Motor vehicle Automotive exhaust Rim Automotive fuel system

^^ after the smoke test i found a massive hole in the lower intake boot elbow. this leak was so big it wasn鈥檛 letting me see any of the other leaks due to the smoke.

Motor vehicle Car Automotive design Personal luxury car Automotive exterior

^^ i also added smoke to the vacuum line connected to the control valve on cylinder head

Hood Automotive tire Motor vehicle Automotive air manifold Automotive exterior

^^ the line goes back behind the engine into the black plastic vacuum control valve for SAP

Hood Automotive tire Motor vehicle Automotive design Automotive exterior

^^ it leaks in this area when i add smoke to the vacuum hose connected to the control valve

any idea what could be leaking behind the intake manifold?
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #31 ·
Use a mechanic鈥檚 mirror and bright light.
Search and read on here to verify, but I think it is expected that the electric air valve vents to atmosphere when closed.
Auto part Font Electronics accessory Rectangle Plastic

i looked for a long time and couldn鈥檛 find anything. also used my phone to record that area. do you think this electric valve is venting when it鈥檚 closed?
 

Premium Member
Z3's 3.0L and 2.8L
Joined
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Well done in finding the vacuum leaks.

There is a number of soft lines behind the manifold for the SAP, plu the valve and a one way valve. Note how the one way valve is plumbed. It's black and white so that helps.


Some reading:

Post #34: Some new codes! 2002 325i intake manifold removal project

Links in post #3: Retrofitted Old-Style SAP ?? MYSTERY
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #33 ·
Well done in finding the vacuum leaks.

There is a number of soft lines behind the manifold for the SAP, plu the valve and a one way valve. Note how the one way valve is plumbed. It's black and white so that helps.


Some reading:

Post #34: Some new codes! 2002 325i intake manifold removal project

Links in post #3: Retrofitted Old-Style SAP ?? MYSTERY
i could barely reach back there. i might just take the intake manifold off to look at all the lines.

wondering if air is supposed to vent out of that electric vacuum valve? because when i pump smoke it comes out in that area.

wondering if that鈥檚 supposed to happen because 鈥淏ali鈥 stated it should vent air out when it鈥檚 off.
 

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2002 330ci-5HP-19, 2004 325ci-M56
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39 Posts
Discussion Starter · #34 ·
Well done in finding the vacuum leaks.

There is a number of soft lines behind the manifold for the SAP, plu the valve and a one way valve. Note how the one way valve is plumbed. It's black and white so that helps.


Some reading:

Post #34: Some new codes! 2002 325i intake manifold removal project

Links in post #3: Retrofitted Old-Style SAP ?? MYSTERY
basically what i鈥檓 asking is if i actually have a vacuum leak back there or is it normal for the valve to vent air when off???
 

Premium Member
Z3's 3.0L and 2.8L
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basically what i鈥檓 asking is if i actually have a vacuum leak back there or is it normal for the valve to vent air when off???
I do not know. Both of my spare inlet manifolds have been stripped of the SAP valves etc, so I can't test it.

The first thread I linked was about getting better access without taking he manifold off. Maybe try that access and see where the smoke comes from.
 

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2002 330ci-5HP-19, 2004 325ci-M56
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Discussion Starter · #36 ·
I do not know. Both of my spare inlet manifolds have been stripped of the SAP valves etc, so I can't test it.

The first thread I linked was about getting better access without taking he manifold off. Maybe try that access and see where the smoke comes from.
thank you !!

so last night all of my monitors got 鈥渞eady鈥 except the secondary air system monitor. right now i have 7 out of 8 monitors ready.

when cold starting in the morning i try to listen if the air pump turns on and it does not! i tested if the connector is getting power and it does get power at cold start. i tested the fuse and relay. i also took the pump out and put power to it. the pump turned on outside the car when i added power. what could be the fault in this system?
 

Premium Member
Z3's 3.0L and 2.8L
Joined
2,630 Posts
Do you have a loose connection? That's the only thing I can think of.
  • Connector has power but pump does not run
  • Pump runs when powered separately
  • The connector terminal tightness has not been tested
 

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2002 330ci-5HP-19, 2004 325ci-M56
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39 Posts
Discussion Starter · #39 ·
Do you have a loose connection? That's the only thing I can think of.
  • Connector has power but pump does not run
  • Pump runs when powered separately
  • The connector terminal tightness has not been tested
i could try cleaning connector with electrical cleaner spray? i noticed it was a little bit greasy/oily around the plugs but don鈥檛 know if it鈥檚 enough to make a difference.
 

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2005 330xi Auto, 2006 330ci Vert Auto
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2,387 Posts
The SAP only runs when the DME thinks it needs to. That typically means a cold start. So if your engine is warm/hot or the DME thinks it's warm/hot or if the ambient temperature is too hot (too hat actually or the ambient temperature sensor is reporting the wrong temperature), the SAP won't be commanded to run.
 
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