[m56valvecovergasket]

hello e46 and bmw community. i recently got a 2004 bmw 325ci with the m56 engine. when i got the car i checked the codes/monitors with a obd scanner. there were no codes and all the monitors were ready at the time. after about a week of driving the service engine soon light came on and it turned out to be a system lean code(s). i believe that code showed because the main intake hose was disconnected, i tightened the clamp properly. unless i have another vacuum leak i believe that was the issue with the SES light. i realized AFTER clearing the codes all the monitors were incomplete. i’ve driven over 200 miles and did two proper cold starts over the last two days. all the monitors are ready except the CCM, Secondary Air System and EVAP are still not ready. even after driving and doing a couple cold starts the CCM, SAS and EVAP will not get ready. i have no codes stored currently. the ambient outside temp is broken and always shows 122 degrees fahrenheit, wondering if that will impact this monitor. can anyone help with this?

 

[m56valvecovergasket]

^^
comprehensive component monitoring - INCOMPLETE

^^
EVAP - INCOMPLETE
secondary air system monitoring - INCOMPLETE

 

[m56valvecovergasket]

thanks for the reply i’m new to the bmw community and am having trouble understanding this chart. how do i utilize this chart to resolve the issue with SAS, CCM and EVAP monitors

 

[m56valvecovergasket]

You look at what is being monitored and what enabling/disabling items there are. Make sure all the enabling/disabling items are correct.

so for example to set the secondary air system monitor the air pump must be on, o2 must be heated up, cold start enrichment must be activated and coolant temp needs to be -10 to 70.5 etc. basically the secondary parameters need to be aligned with enable/disable conditions?

 

[m56valvecovergasket]

Old lazy pre-cat O2 sensors can cause SAP monitor not ready. Are they perky at cold start? How long before they start switching?

what do you mean by perky at cold start? and what do you mean by when they start switching? sorry confused

 

[m56valvecovergasket]

Read up on how pre-cat O2 sensors work and you will understand.

• Fuel Management Dissertation
• Fuel Trims Explained

how can i test my pre cat o2 sensors

 

[m56valvecovergasket]

i’m waiting for the adapter in the mail. here is a video from my obd scan tool wondering if this has anything to do with this. thank you for your help so far

 

[m56valvecovergasket]

1) With a scanner that shows you live data. The sensors should be switching/swinging in value. As you have a 2004 model E46, you will have wide band O2 sensors these swing around a 1 mA mark e.g. 0.94 to 1.06 mA with a hot engine at idle.

2) Check with a scanner that the O2 sensor heating is > 90%.

3) Set up OBD Fusion and run the 3 standard logs. Post links to the CSV files and we'll have a look.

 

[m56valvecovergasket]

First Video, go into 4) Live Data. Find and select the O2 sensors and watch the numbers.

here is a video of the live data. a little bit long but around 1 minute 50 seconds into the video i started increasing rpm

 

[m56valvecovergasket]

Engine coolant showing 154 F is not up to full temperature, so it is still in cold start enrichment.
Get the engine up to at least 200 F and then look at the fuel trims.

alright i will idle the car until coolant temp shows 190-200 fahrenheit and upload another video

 

[m56valvecovergasket]

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

here is a video of the fuel trims when engine is at operating temperature. i noticed when the engine is cold both of the STFT is in normal range but both LTFT is 10.9. 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.

 

[m56valvecovergasket]

i will be doing a smoke test tomorrow. i’ll hook up the smoke directly to the intake for the test. i know i have a leak behind the intake manifold near firewall on driver side somewhere i just need to find it

 

[m56valvecovergasket]

Video 1 - Fault Report

 

[m56valvecovergasket]

Video 2 - o2 sensor control/mixture

 

[m56valvecovergasket]

Video 3 - engine operating values

 

[m56valvecovergasket]

The second video confirms adapted lean condition, so smoke test and leak fixing is the next step. 👍

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 👍

 

[m56valvecovergasket]

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 “mass air flow” value was around 11.3 kg/h
i’m wondering if this maf value is correct?

 

[m56valvecovergasket]

Yes, it's about 3 g/s

^^ after the smoke test i found a massive hole in the lower intake boot elbow. this leak was so big it wasn’t letting me see any of the other leaks due to the smoke.

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

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

^^ 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?

 

[m56valvecovergasket]

Use a mechanic’s 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.

i looked for a long time and couldn’t find anything. also used my phone to record that area. do you think this electric valve is venting when it’s closed?

 

[m56valvecovergasket]

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:

SAP vacuum switch access - solved

A tip for SAP failure when no vacuum is present on the control valve that sends fresh air (pump output) to the exhaust manifold. I've seen a few DYI's that miss a couple tricks. When you have to dive behind the drivers side, rear engine location to remove the switch, you may have difficulty...

www.e46fanatics.com

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’s supposed to happen because “Bali” stated it should vent air out when it’s off.