Strange exhaust NOISE..... - The Unofficial BMW M5 Messageboard (m5board.com)

m5 rus · 9th August 2004, 12:06

Hello everybody..

..I need some help...

1) Ok. My car runs fine most of the time....last time I diagnoisted..it showed some CAMS sensor faults...or other sensor...I dont know how to call it in English...M5 has 4 of them, 2 on top, 2 at bottom...

...

2) Other mistake was throtle potentiamer....looks after throtle balance....when standing steel...Rev would start jumping 0.5-1000RPm's...then disappear...

3) And the last thing I notice when I start the car in the morning...I turn on...it wont start....then 2nd time...it start fine...and then all day is fine..next morning the same story... what can this be

Sometimes my car start to make wierd exhaust noise....loose power...sound like a Subaru, burbling sound...B-r-r-r...then it disappears...espacially when its HOT...and driven slowly...

Does anybody know what can cause my car to make this strange noise and some loss in performance....IS this change is sound caused by one of those Sensors...or

...

Overall everything fine...but noise prob start to occur more often...

Anybody have any ideas???

SC'dKellenersM5 · 9th August 2004, 13:18

sounds like a cam shaft position sensor or a vanos control unit has let out on you

m5 rus · 9th August 2004, 14:04

Quote:

Originally Posted by RennSportSC'dKellenersM5

sounds like a cam shaft position sensor or a vanos control unit has let out on you

Diagnostic showed left bottom CAMS shaft sensor faulty... Strange exhaust noise can come from CAN COME FROM it been FAULTY...

Vanos control unit??? CAn it be diagnosted??? Is it expensive???

SC'dKellenersM5 · 9th August 2004, 14:08

the vanos unit may be expensive..dont really know

but it sounds like the position sensor for the cams

Tin · 9th August 2004, 15:21

Quote:

Originally Posted by RennSportSC'dKellenersM5

the vanos unit may be expensive..dont really know

but it sounds like the position sensor for the cams

If is the camshaft sensor (Bluebomber) did a quick howto to changing the sensor your self.. try a search on his username. its only a 5mm hex bolt and wire clip holding the sensor in. Sensor itself is around £50.. but there are 2.. inlet and outlet sensors (different mounting positions etc).. find out which one you need..

Tin

m5 rus · 9th August 2004, 17:17

Quote:

Originally Posted by Tin

If is the camshaft sensor (Bluebomber) did a quick howto to changing the sensor your self.. try a search on his username. its only a 5mm hex bolt and wire clip holding the sensor in. Sensor itself is around £50.. but there are 2.. inlet and outlet sensors (different mounting positions etc).. find out which one you need..

Tin

Thanks guys....I think I need a left outjet sensor...

So you guys think this sensor can cause that RICE ROCKET EXHAUST NOTE sometimes

DrewKeen · 9th August 2004, 19:25

Everyone that has had one go has posted about a terrible exhaust note. I consider a rice rocket exhaust sound terrible so my thoughts are yes.

Ahmed · 9th August 2004, 20:24

m5 rus..

I have the exact same problems you are having.... EXACTLY!

My RPM plays when idling, i lose power and engine and exhaust noise changes while driving.... and sometimes goes back to normal while driving as well. I lost power at high RPM..... i hate my car right now!

New MAF's are going in this week.... but i want to get to the bottom of this ( which should not include VANOS unit hopefully )

m5 rus · 10th August 2004, 11:26

Quote:

Originally Posted by Ahmed

m5 rus..

I have the exact same problems you are having.... EXACTLY!

My RPM plays when idling, i lose power and engine and exhaust noise changes while driving.... and sometimes goes back to normal while driving as well. I lost power at high RPM..... i hate my car right now!

New MAF's are going in this week.... but i want to get to the bottom of this ( which should not include VANOS unit hopefully )

Ahmed...

I thought that one of those CAM sensors cause our BEAST's to make that B-r-r-r-r sound.... NOW I am Sure...Will order new sensor today...

If you REV's jumping 0.5-1000 RPM...and diagnoistics say it's throtle potentialmeter..then...TRY 1st to balance your throtles...it takes a technician about 3hours....and need a special equipment that only BMW has...although in some cases BMW will say that they only balace NEW throtles when they are installed, the OLD one can be balanced as well...cost $200 for labour..new throtles would cost about $1000+...

I've diagnosted my M5 over 5 times over 2 months...as soon as my car went into failsafemode...throtle mistake shown 255times....then it disappeared...now it fine 99%...Rice rocket sound occurs once a day then disappears...

1st will replece a sensor, do diagnostic's....if throtle mistake...then will balance a throtles...if doesn't help then

will need to get new throtles...

Good LUCK...