Rev hesitation on low rpm

[cyne]

Hi All,

Recently, felt the car has a judder feeling on cold starts while idling. And when revving without in gear, there's a slight hesitation below 2K, and rev smoothly after that.

After warming up, judder feeling is gone but rev hesitation still persist.

Could it be the Ignition coils ? 3 weeks ago, I did a scan with INPA (mech's laptop) it didn't have any errors.

Need help..

Thanks

 

[slyder]

compression test? cam sensor? crank sensor?

 

[jarance]

ICV?

 

[kw930]

Could be Vanos issue?

 

[cyne]

I will leave Vanos out... since it happens on low RPMs. Cam or crank sensor should throw out some error codes right ?

ICV... hmm...

 

[bimmerholic]

Possibly coils or plugs. If plugs are faulty by visual inspection, change them. May solve.

 

[huskar3399]

DISA is associated with low rpm. Get that checked as well.


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[kw930]

Yup DISA is possible. Can hear whether got rattling sound or not during reving?

 

[cyne]

Odd enough... I used my newly acquired cable and INPA to reset the adaptation values last night. This morning, it was smooth... This DISA is kinda new to me. Do I need to dismantle to see if its bad ?

I don't hear a rattle sound by revving. Just some sort of a misfiring sound below 2K rpm.

I've rerun the check again using INPA, no error codes on the engine, as per what my mech scanned 3 weeks ago.

 

[kw930]

Odd enough... I used my newly acquired cable and INPA to reset the adaptation values last night. This morning, it was smooth... This DISA is kinda new to me. Do I need to dismantle to see if its bad ?

I don't hear a rattle sound by revving. Just some sort of a misfiring sound below 2K rpm.

I've rerun the check again using INPA, no error codes on the engine, as per what my mech scanned 3 weeks ago.

I've created a topic in E46 forum about DISA, maybe you may refer it :
http://www.bmwclubmalaysia.com/newforums/index.php?/topic/36640-adjuster-unit-disa-failure-replacement/

 

[cyne]

Alright.. just confirmed.. 1st coil shot ! replaced 1 pc RM94 BREMI. Now its smooth again.
Now I am wondering, why didn't it throw any error codes with INPA ?

 

[huskar3399]

Alright.. just confirmed.. 1st coil shot ! replaced 1 pc RM94 BREMI. Now its smooth again.
Now I am wondering, why didn't it throw any error codes with INPA ?

that's my observation as well. some errors only appears using BMW scanner and not INPA. no idea why.

 

[anakin]

Alright.. just confirmed.. 1st coil shot ! replaced 1 pc RM94 BREMI. Now its smooth again.
Now I am wondering, why didn't it throw any error codes with INPA ?

Cyne..how to confirm?

 

[cyne]

Mech opened up the cover. I reved, and the first coil was giving tak tak tak sound. Took it out and it had a bad burnt smell