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LifeOfDesire

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About LifeOfDesire

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Garage

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    2002 E39 525d Touring SE

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  1. LifeOfDesire

    Unplugging the MAF on a 525d

    Looks like I'm going to have to test the wiring then. Could the hesitation be something to do with the battery voltage? Mine often reads 13.5V which is low and the battery has been flattened several times in the past few years. I don't think the charging capacity is that high either. @Clavurion It says on that link the DDE supplies the MAF with battery voltage so if the battery is knackered could it be interfering?
  2. LifeOfDesire

    Unplugging the MAF on a 525d

    Currently I have a problem no garage seems to be able to diagnose, where the car hesitates significantly at random moments on acceleration when the MAF is plugged in. If I drive the car with it unplugged it goes away completely, but obviously it uses more fuel and there is little power below 2k RPM. From what I have read so far unplugging the MAF disables the MAF sensor, MAP sensor, and EGR activation. I have replaced both MAF and MAP sensors, and plugged the vacuum tube on the EGR so it stops working, but the hesitation still occurs. It also occurs with the MAF plugged in and with the MAP unplugged so I do not believe it is the MAP at the moment. I am looking for a full list of what unplugging the MAF actually does so I can try and narrow down what is causing the problem. Thank you!
  3. LifeOfDesire

    Oh no! Touring rear suspension gone flat

    When I replaced one of my rear air springs I used Arnott, they seem to be the best. https://www.onlinecarparts.co.uk/arnott-13243666.html Not sure how to fit it as I got a garage to do it for me. Just be aware right and left are different part numbers. Left ends in 3, right ends in 4.
  4. LifeOfDesire

    525d MAP Sensor Brand

    Just wondering what brand is OEM for the MAP sensor? Can't see a Bosch, Pierburg, or Siemens one anywhere. Thanks.
  5. LifeOfDesire

    2002 525d Hesitation problem

    Here is an update and some pictures of the times that I have managed to catch the stuttering in the data. I already knew the charge air pressure was dropping well below specified when it stuttered, but I have now noticed that actual air mass is dropping well below specified when it stutters too. I had a new Bosch MAF sensor fitted last year so it shouldn't be that, unless it somehow needs coding. Would that be done in ISTA/P?
  6. LifeOfDesire

    2002 525d Hesitation problem

    Additionally I have a laptop and cable ordered for tomorrow that I will put Rheingold on so I can look at all the data myself.
  7. LifeOfDesire

    2002 525d Hesitation problem

    I am replacing the turbo pressure converter and the vacuum lines for it as well this week, will see if that fixes anything. I looked at the charge pressure when it was driving, and when it stuttered, it dropped well below where it should have been, so obviously the turbo is dropping out when it stutters. Given that no such stuttering ever occurs when the MAF is unplugged, it seemed more likely to me that it would be a sensor (or the pressure converter) fault rather than a mechanical fault like a vacuum line splitting. I would have thought that, if there were a mechanical issue as opposed to an electrical one, it would still stutter with the MAF unplugged. Can anyone confirm whether unplugging the MAF forces the turbo pressure converter to use a 'default' or failsafe setting? Obviously unplugging the MAF causes the ECU to use a failsafe mode but I was unsure whether this affected the pressure converter.
  8. LifeOfDesire

    2002 525d Hesitation problem

    If it can get past 3k RPM then it tends to keep pulling, but quite often when the hesitation gets bad it can't even accelerate hard enough even if I put my foot to the floor.
  9. LifeOfDesire

    2002 525d Hesitation problem

    Thank you for your help, I am just wondering what would happen if I were to unplug the fuel rail pressure sensor on the end of the fuel rail towards the bulkhead? This is just to test and see if this sensor is the culprit. I have tried unplugging the fuel filter pressure sensor but it didn't solve it. No. 8 on this diagram: https://www.realoem.com/bmw/enUS/showparts?id=DP02-EUR-01-2002-E39-BMW-525d&diagId=13_2041
  10. LifeOfDesire

    2002 525d Hesitation problem

    For a while now I have had a problem with my 525d hesitating a lot when cold and also hesitating when turning left. Recently I discovered that the MAP sensor had literally snapped off almost and was causing the hesitation when turning left, however, it did not solve the hesitation when cold and now it hesitates for at least a second at around 2000-2500RPM. Today it got so bad for some reason that it would barely accelerate, and I had to pull over and pull out the MAF sensor because for some reason that cures it (although it goes into a failsafe mode). I have replaced the MAF sensor entirely so I do not believe this to be the issue. I have done a smoke test, replaced the intercooler to EGR pipe and the EGR is disabled so this is not the issue. I also blanked off the swirl flaps last week so this is not the issue. MAP sensor is new and I have tried driving with it unplugged and it still stutters so that is not the issue. Here is an example of the hesitation, bear in mind it doesn't matter how hard I go on the throttle it still does the same thing: https://www.youtube.com/watch?v=Z0U848tOw14 The only other thing is that two injectors seem to have values that are massively off, though given that the car never hesitates with the MAF unplugged I don't see how this would be causing it: https://i.imgur.com/iwbAlfo.jpg Thanks
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