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Stock Problems/IssuesDiscussions related to warranty related issues and repairs, or other problems with the OEM parts and software for MINI Clubman (R55), Cooper and Cooper S(R56), and Cabrio (R57).
I am at wits end trying to sort out our 2009 Clubman S. This is a manual transmission car, and a year ago I removed the engine to do clutch/timing chain/decarbon the intake. I have reinstalled the engine and it will occasionally run fantastic, but then I get home and it won’t start. And sometimes it will start and run but have no power to the point that it can’t make it up the hill from our house to the main road. And then other days it will run fine, for example I recharged the a/c system and it sat idling in the driveway for 20 minutes until I was done. I shut it off to get my wallet and phone and it started right up, did a fantastic test drive, and then when I came home it would not start again.
I am getting error codes 2B51 or 2B5B which suggest problems with the MAF sensor. Alternatively, this sounds like the mysterious JBE failure, but neither seem to be invovled.
Things I have replaced or checked:
new high pressure fuel pump
new low pressure fuel pump
new MAF sensor, and verifed wiring harness between MAF and DME
new throttle body
had fuel pump relay in the JBE repaired by Automotive Circuit Solutions
smoke-tested the intake system for vacuum leaks
It seems like something may be failing when it gets warm, but I can’t think what is left to check, other than sending the JBE back to get re-checked.
Any wisdom from the hive-mind?
Collect and save MAF live data with a scan tool when engine runs and starts fine. Compare latter data to MAF live data when engine runs poorly or won't start. Any differences?
The common no-start JBE issue is linked to a failure of the fuel pump to run. Have you checked that?
Collect and save MAF live data with a scan tool when engine runs and starts fine. Compare latter data to MAF live data when engine runs poorly or won't start. Any differences?
The common no-start JBE issue is linked to a failure of the fuel pump to run. Have you checked that?
The MAF codes are intermittent, which is what drives me crazy. They will seem to alternate.
What type of data will the MAF generate. So far I think I just see air flow.
Yes, the MAF sensor measures air flow rate. I have my scan tool set to report grams/sec of air flow, but you can choose your favorite units.
You can also view freeze frame data for the two MAF codes to see whether throwing the codes correlates with abnormal MAF sensor readings and engine performance or starting problems.
Last edited by Maybe, maybe not; Sep 7, 2024 at 03:21 PM.
Also, did you check whether the PCV diaphragm is leaking air into the air intake?
That’s a good idea, I had not checked that yet.
I also am wondering if the fuel injectors might have gotten gummed up in the months that the car was on jackstands. That might explain why here seems to be fuel delivery issue even though the pump has been replaced and the high pressure fuel rail seems be be reading in the normal range.
If there's an intermittent fueling problem, then spraying starting fluid into the air intake would allow the engine to start when the cranks-but-won't-start condition reappears.
Also, did you check whether the PCV diaphragm is leaking air into the air intake?
Is this the PCV diaphram housing peaking out from under the cover on my valve cover? I replaced the valve cover 3 years ago so I assumed the PCV system would still be intact, but it is worth checking. I’m not sure how to test it, as I don’t hear an obvious whistling? Is it worth taking apart to examine the diaphram?
So I’m getting more confused the deeper I go into this. Today I started the car up and let it idle for 20’ while I checked for vacuum leaks, and then it just died. So I hooked up my Autel scanner and recorded fuel pressure, air flow from MAF, and engine rpm, and then tried to start the car. I did this 3-4 times with the same result shown in the screen shot below. On startup all the indicators rise, and then the rpm drops as the engine stumbles. I can blip the throttle a couple of time to keep the engine running roughly, but ultimately it stalls.
I pulled off the airbox and installed a fuel pressure gauge, and the in-tank pump appears to be working as I got 70 psi. The high pressure fuel rail showed between 700-900 psi so I thing the fuel delivery system is fine.
It seems as if the DME is not controlling the injectors so that it loses fuel. I know the wiring from the MAF to the DME is good. I’m left wondering if the charge pressure sensor just before the throttle body went bad and is sending inconsistent data to the MAF, which is then sending incorrect data to the DME. Alternatively, could the DME be bad in such a selective manner? All the other functions appear to be working.
We looked under the exhaust manifold to see if anything might be disconnected, and noticed this port on the throttle body housing. It looks like it takes a push-on connector like the one next to it, but I can’t find any unconnected lines nearbt. It does not appear to be connected on the N14 engine as tapping with a small screwdriver suggested the port was blocked off internally, although I might have felt a depression off to the firewall side internally. Is this port connected on the N14?
Did one or both MAF fault codes reappear during any of the tests?
I am assuming that the graph x-axis (time) is seconds. Correct?
The air flow rate readings around 12 sec and 13.5 sec show as flat topped plateaus. Does this mean that the peak air flow rate readings at those times were truncated in the graph and therefore were actually much higher than shown? You may have to graph the air flow rate data alone to reveal the actual peak values.
...noticed this port on the throttle body housing. It looks like it takes a push-on connector like the one next to it, but I can’t find any unconnected lines nearbt.
Next time you get the engine running, put your finger over the port hole. Do you feel any air movement?
You mention that the engine ran for 20 minutes. Did it start and idle normally? But after stalling, the engine ran poorly. This would suggest that the engine runs well after a cold start but stumbles only after it reaches normal operating temperature. Thoughts?
Next time you get the engine running, put your finger over the port hole. Do you feel any air movement?
You mention that the engine ran for 20 minutes. Did it start and idle normally? But after stalling, the engine ran poorly. This would suggest that the engine runs well after a cold start but stumbles only after it reaches normal operating temperature. Thoughts?
Good idea about putting a finger over the mystery port; we did while the engine was bucking and not starting and did not feel a pulse, but need to repeat when the engine runs.
One other data point: When the engine was running, we got the same MAF readings whether the MAF was plugged in or not. We measured 20 lb/hr airflow at idle, and the between 80-90lb/hr at 3000 rpm with the MAF plugged in or disconnected. This makes me think the MAF is either not functioning (it’s a replacement) or is not getting a good signal from the charge sensor just before the throttle body. Perhaps the charge sensor is going wonky?
But the real mystery is why it runs fine for 20-30 minutes and then fails. To me it seems like something is failing either with time or temp, and the temps are not getting very high after only 20 minutes, the aux fan doesn’t even kick on yet.
One other data point: When the engine was running, we got the same MAF readings whether the MAF was plugged in or not. We measured 20 lb/hr airflow at idle, and the between 80-90lb/hr at 3000 rpm with the MAF plugged in or disconnected. This makes me think the MAF is either not functioning (it’s a replacement) or is not getting a good signal from the charge sensor just before the throttle body. Perhaps the charge sensor is going wonky?
Some questions:
1) With the engine idling, you measured a 20 lb/hr air flow rate. But when you unplugged the MAF with the engine still idling, the air flow rate remained at 20 lb/hr. Correct? With the MAF still unplugged and engine now running at 3K rpm, did the air flow rate increase to 80-90 lb/hr or did it remain at 20 lb/hr?
2) Did unplugging the MAF have any effect on the engine, such as a change in idle speed or rough running, and did it cause a MAF sensor fault code?
3) What was the engine or coolant temperature after 20-30 min of running? Next time you plan to do a cold start, monitor the coolant temperatures before the start, after the start while the engine runs well, and just until the engine begins to run poorly. Are your coolant temperature readings during the 20-30 minute test surprising/abnormal?
Just for comparison, my stock 2012 Mini Cooper with the N16 engine (no fault codes and runs perfectly) idles at 750 rpm and, at this idle speed, the MAF air flow rate is 26.8 lb/hr. Ambient temperature was about 90F.
At 2345 rpm, the MAF air flow rate is 176.7 lb/hr.
Does your MAF sensor issue under report the air flow rate to the DME, thereby causing your engine to run lean?
Last edited by Maybe, maybe not; Sep 9, 2024 at 09:49 PM.
1) With the engine idling, you measured a 20 lb/hr air flow rate. But when you unplugged the MAF with the engine still idling, the air flow rate remained at 20 lb/hr. Correct? With the MAF still unplugged and engine now running at 3K rpm, did the air flow rate increase to 80-90 lb/hr or did it remain at 20 lb/hr?
2) Did unplugging the MAF have any effect on the engine, such as a change in idle speed or rough running, and did it cause a MAF sensor fault code?
3) What was the engine or coolant temperature after 20-30 min of running? Next time you plan to do a cold start, monitor the coolant temperatures before the start, after the start while the engine runs well, and just until the engine begins to run poorly. Are your coolant temperature readings during the 20-30 minute test surprising/abnormal?
Yes, the odd thing was that unplugging the MAF didn’t seem to have any effect on the engine. It idled at 20 lb/hr with the MAF plugged or unplugged. I kind of expected this, but the surprising thing was how the airflow rate was essentially the same at 3K rpm with or without the MAF. Unplugging the MAF from the idling car did not appear to have any effect on idle speed or poor running. I didn’t check for new fault codes, but I should do that when I repeat the test again, along with monitoring the coolant temps. I’ll add that the engine did not seem to be getting hot, as the aux fan didn’t kick in.
Just for comparison, my stock 2012 Mini Cooper with the N16 engine (no fault codes and runs perfectly) idles at 750 rpm and, at this idle speed, the MAF air flow rate is 26.8 lb/hr. Ambient temperature was about 90F.
At 2345 rpm, the MAF air flow rate is 176.7 lb/hr.
Does your MAF sensor issue under report the air flow rate to the DME, thereby causing your engine to run lean?
This is I think part of the problem, but this is a replacement MAF sensor, so unless both MAF sensors were bad, I’m wondering about something else in the process of reporting airflow to the DME. The only other component that I know of is intake pressure sensor (13627540508) just before the throttle body or the manifold pressure sensor (13627535069). I wonder if bad data from the pressure sensor is giving the MAF bad data, which in turn is sending bad data to the DME?
Last edited by idickers; Sep 10, 2024 at 03:43 AM.
Yes, the odd thing was that unplugging the MAF didn’t seem to have any effect on the engine. It idled at 20 lb/hr with the MAF plugged or unplugged. I kind of expected this, but the surprising thing was how the airflow rate was essentially the same at 3K rpm with or without the MAF.
The MAF is clearly able to detect airflow rate differences as evidenced by the lower airflow seen at idle versus the higher airflow seen at 3K rpm.
I'm less concerned about your MAF sensor disconnection observations because I presume that the scan tool just continues to report the last MAF sensor signal received before disconnection.
This is I think part of the problem, but this is a replacement MAF sensor, so unless both MAF sensors were bad, I’m wondering about something else in the process of reporting airflow to the DME. The only other component that I know of is intake pressure sensor (13627540508) just before the throttle body or the manifold pressure sensor (13627535069). I wonder if bad data from the pressure sensor is giving the MAF bad data, which in turn is sending bad data to the DME?
I am getting error codes 2B51 or 2B5B which suggest problems with the MAF sensor.
These^ codes have compelled me to remain focused on the MAF circuit.
Did your scan tool provide similar descriptions for the two fault codes (https://bmwfault.codes/) to those shown below?
Can you summarize all electrical tests that you have done so far on the MAF circuit?
Last edited by Maybe, maybe not; Sep 10, 2024 at 08:11 AM.
I have confirmed that the wiring harness between the MAF meter and the DME is good.
I replaced the MAF and the throttle body and got the same error codes.
If my flow numbers are correct, then at load my turbo car is supplying less air (80-90 lbs/hr) than your NA car (177 lb/hr). Or, my MAF thinks it’s supplying lower values (if the flow rate comes from the MAF) and is decreasing fuel to match.
The only thing I haven’t done yet on the repair options from the BMW fault code tables is replace the DME.
I have confirmed that the wiring harness between the MAF meter and the DME is good.
MAF circuit electrical tests are extremely tricky because both MAF codes are intermittent. Note that you only learn something from the electrical tests when the MAF code(s) is active. If that eventually happens, be prepared to do both end-to-end continuity tests and short to ground tests on all 4 MAF sensor wires. Also measure the DME reference voltage at pin 1 of the MAF sensor connector.
I ran the car again today while monitoring MAF flow and coolant temp. This time, it ran fine for 40 minutes with normal coolant temp; 189F eventually creeping up to 220 when the aux fan kicked on. The airflow looked about the same as yesterday.
However, I did see that yesterday’s shenanigans triggered two new fault codes:
00289D Digital Motor Electronics (DME), boost pressure sensor, electric
002EF2 Digital Motor Electronics (DME), Intake Air Temperature (IAT) sensor signal
They were not present today, but this intermittent sensor error might agree with the theory that the MAF is getting bad data which it is passing on to the DME.
I did see that yesterday’s shenanigans triggered two new fault codes:
00289D Digital Motor Electronics (DME), boost pressure sensor, electric
002EF2 Digital Motor Electronics (DME), Intake Air Temperature (IAT) sensor signal
They were not present today, but this intermittent sensor error might agree with the theory that the MAF is getting bad data which it is passing on to the DME.
I agree that any fault codes potentially related to the problem are fully worthy of pursuit.
