wierd sound in engine

[JLV1717]

all sifu2,i just buy an e46 325i 2004.during a high speed bout 160-180 for about 50km-80km constanly wierd sound come out from engine i think.. the more i push the peddle strong sound follow and the car feel so heavy to accelerate. before that it was very powerful.i stop for a while and continue journey until certain distance with high speed this thing happen again. so2 pening ..... why?

 

[oligokoko]

all sifu2,
i just buy an e46 325i 2004.during a high speed bout 160-180 for about 50km-80km constanly wierd sound come out from engine i think.. the more i push the peddle strong sound follow and the car feel so heavy to accelerate. before that it was very powerful.i stop for a while and continue journey until certain distance with high speed this thing happen again. so2 pening ..... why?

how is d sound like? this might b d DISA valve

 

[JLV1717]

what is DISA valve.how to check? sound like gooooooonggggggggggggg

 

[oligokoko]

what is DISA valve.how to check? sound like gooooooonggggggggggggg

DISA valve is a mechanism tht controls ur intake manifold length. on low revs it will remain closed (short) to provide the engine with better flow of air into the combustion chamber. on high revs, it will open (long) to provide combustion chamber with more air due to the high load of the engine.

to confirm this device is not working, u can try touching on the DISA valve and u might feel a vibration, the sound should be like a flickering sound. u can also try to disconnect the DISA valve socket and hear the noise, if the noise is gone, then DISA valve is the culprit. just 2 remind u before u do this, make sure that u r at any workshop with BMW diagnostic tester unit coz when disconnecting a DISA valve, this might bring up the engine warning light ON.

i cannot confirm this coz i have not heard the sound yet. its hard 2 say coz a faulty DISA valve should sound like something flickering, but in your case, its a gooonng sound. might b something else. please bring it to ur nearest SC to confirm.

happy troubleshooting!

p/s : DISA valve is number 7 in the image

 

[oligokoko]

These few pics might help u also 2 understand n locate DISA valve

Happy Troubleshooting!

 

[JLV1717]

thanks for the info