E39 M5 problems - HELP!
Discussion
I posted a while back saying that I was having a problem with the car 'misfiring' at about 4500-5000rpm then going into 'safe mode'. This was widely regarded as being due to an issue with the MAFs. I got a second hand pair out of the same age and model of car and these seemed to do the trick - the car ran fine up to the redline.
HOWEVER, another problem immediately began. The car now 'surges' on idle and will sometimes stall when coasting up to junction etc in 1st or 2nd gears. A mechanic that I recently took it to thought that it was also surging during normal driving too, although it's more noticeable at low revs. He also thought it wasn't as 'sharp' on open throttle as previous E39 M5s he's driven.
It's very odd that one problem goes away by changing the MAFs but another one begins! It does appear to be an MAF issue given the immediate effect when the MAFs are inter-changed. Or could it be a bigger ECU issue? At the moment I'm stumped. Any advice would be most welcome - I've had the car for 3 months now and it's never run right. Cheers in advance.
Stevem5 said:
I had the cutting out problem, turned out to be a CPS (Cam poisition Sensor) I belive there are 4 (preparing to be shot down). The other one is Oxygen sensor.
Has your mechanic read the fault codes, as both these should register?
Steve
Mechanic read the codes and the O2 sensor came up but I think that was an old code as the sensor was replaced quite recently (I'm assuming after the code originally came up). Never came up with a cam position sensor code though...Has your mechanic read the fault codes, as both these should register?
Steve
ViperScot said:
I've had the car for 3 months now and it's never run right. Cheers in advance.
Hope you get it sorted soon... I saw your car at JD's when I was picking up my Evo at the weekend.... Dave was pretty puzzled to the problems, he did think it may be related to you fitting non genuine BMW MAF sensors, did you not fit the equivilant VAG part? He said they are very fussy engines when it comes to MAF's. Good luck. Edited by scz4 on Thursday 10th July 09:40
scz4 said:
ViperScot said:
I've had the car for 3 months now and it's never run right. Cheers in advance.
Hope you get it sorted soon... I saw your car at JD's when I was picking up my Evo at the weekend.... Dave was pretty puzzled to the problems, he did think it may be related to you fitting non genuine BMW MAF sensors, did you not fit the equivilant VAG part? He said they are very fussy engines when it comes to MAF's. Good luck. Edited by scz4 on Thursday 10th July 09:40
ViperScot said:
I posted a while back saying that I was having a problem with the car 'misfiring' at about 4500-5000rpm then going into 'safe mode'. This was widely regarded as being due to an issue with the MAFs. I got a second hand pair out of the same age and model of car and these seemed to do the trick - the car ran fine up to the redline.
HOWEVER, another problem immediately began. The car now 'surges' on idle and will sometimes stall when coasting up to junction etc in 1st or 2nd gears. A mechanic that I recently took it to thought that it was also surging during normal driving too, although it's more noticeable at low revs. He also thought it wasn't as 'sharp' on open throttle as previous E39 M5s he's driven.
It's very odd that one problem goes away by changing the MAFs but another one begins! It does appear to be an MAF issue given the immediate effect when the MAFs are inter-changed. Or could it be a bigger ECU issue? At the moment I'm stumped. Any advice would be most welcome - I've had the car for 3 months now and it's never run right. Cheers in advance.
Cam sensors by the sounds of it.HOWEVER, another problem immediately began. The car now 'surges' on idle and will sometimes stall when coasting up to junction etc in 1st or 2nd gears. A mechanic that I recently took it to thought that it was also surging during normal driving too, although it's more noticeable at low revs. He also thought it wasn't as 'sharp' on open throttle as previous E39 M5s he's driven.
It's very odd that one problem goes away by changing the MAFs but another one begins! It does appear to be an MAF issue given the immediate effect when the MAFs are inter-changed. Or could it be a bigger ECU issue? At the moment I'm stumped. Any advice would be most welcome - I've had the car for 3 months now and it's never run right. Cheers in advance.
Do you get a change in exhaust note followed by a power drop?
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