1M newby question

[Fahrvergnügen]

Just got my 1M last week and been driving it around a bit. I noticed when I have the AC on and shifting between 2k-4k rpm (normal driving) there is a slight jolt or bucking that occurs. If I let the clutch out real slowly I can eliminate it but when I just shift fast or normal it does this. At higher RPMs everything is fine and the same things happen regardless if in M mode or not.

Am I just getting lazy shifts or am I low on trans fluid or what? I've driven all sorts of manuals with no symptoms like this including e89 Z4, M4, e36 M3 thanks.

[Mdawood]

Originally Posted by Fahrvergnügen

Just got my 1M last week and been driving it around a bit. I noticed when I have the AC on and shifting between 2k-4k rpm (normal driving) there is a slight jolt or bucking that occurs. If I let the clutch out real slowly I can eliminate it but when I just shift fast or normal it does this. At higher RPMs everything is fine and the same things happen regardless if in M mode or not.

Am I just getting lazy shifts or am I low on trans fluid or what? I've driven all sorts of manuals with no symptoms like this including e89 Z4, M4, e36 M3 thanks.

I could be completely wrong but I think you just have to get used to the car.

[CarJunkie]

RPM's drop faster when the AC is on, so revmatching shifts will definitely feel different than without AC. You'll feel it more that other cars because there isn't as much sound deadening or soft bushings to absorb the mechanical jolt.

[OneM]

Maybe the previous owner changed to an aftermarket clutch..?

[champignon]

Originally Posted by OneM

Maybe the previous owner changed to an aftermarket clutch..?

I think there is a dead mouse in there. The best way to dislodge him would be to have few hard shifts, since his remains are likely somewhat attached to the gearing.

Don't drop the transmission, but give it a jolt, and I think you will find that he will fall off the gears and exit the car underneath you. Don't try this at home :-)

[Dackelone]

I think what you are feeling is the CDV. I think you should do the "CDV delete" mod. It will make the clutch feel so much better.


See my post #97...
http://www.1addicts.com/forums/showt...82#post6872882

Also read this thread of what other 1M owners think of this mod.
http://www.1addicts.com/forums/showthread.php?t=558362

Dack

[Fahrvergnügen]

Originally Posted by Dackelone

I think what you are feeling is the CDV. I think you should do the "CDV delete" mod. It will make the clutch feel so much better.


See my post #97...
http://www.1addicts.com/forums/showt...82#post6872882

Also read this thread of what other 1M owners think of this mod.
http://www.1addicts.com/forums/showthread.php?t=558362

Dack

Thanks, this is what I think it is, too. I was searching around a lot last night and I finally came upon articles around the CDV and there seemed to be some articles about it for the 1M and how it makes a world of difference. Checked in with the previous owner he said he never messed with it and hated driving around with the AC on and mainly sweat his ass off. I am not that handy at the moment and am taking it in to my mechanic to replace with a modified CDV.

[ayao]

Originally Posted by CarJunkie

RPM's drop faster when the AC is on, so revmatching shifts will definitely feel different than without AC. You'll feel it more that other cars because there isn't as much sound deadening or soft bushings to absorb the mechanical jolt.

I'm with CarJunkie on this one.
Does the phenomenon go away if the AC is off? If so, there's your answer.
If the phenomenon remains with the AC off, then go chasing other causes, like CDV.

[CarJunkie]

Originally Posted by Fahrvergnügen

Thanks, this is what I think it is, too. I was searching around a lot last night and I finally came upon articles around the CDV and there seemed to be some articles about it for the 1M and how it makes a world of difference. Checked in with the previous owner he said he never messed with it and hated driving around with the AC on and mainly sweat his ass off. I am not that handy at the moment and am taking it in to my mechanic to replace with a modified CDV.

The CDV can be modified on the spot with a small punch. The valve restrictor is metal and sits within the housing, and can be punched out easily. Then replace the empty valve housuing and voila. Very easy DIY also.

[nachob]

Originally Posted by Fahrvergnügen

Just got my 1M last week and been driving it around a bit. I noticed when I have the AC on and shifting between 2k-4k rpm (normal driving) there is a slight jolt or bucking that occurs. If I let the clutch out real slowly I can eliminate it but when I just shift fast or normal it does this. At higher RPMs everything is fine and the same things happen regardless if in M mode or not.

Am I just getting lazy shifts or am I low on trans fluid or what? I've driven all sorts of manuals with no symptoms like this including e89 Z4, M4, e36 M3 thanks.

Sorry you're having this issue and all of the people replying are great resources on here. I have done CDV deletes on two previous e46 BMWs and they made a difference but I have NOT done it on either of my two 1Ms. Unlike the e46 I felt the clutch engagement was great and very firm. Sometimes you even feel a thump which is normal so I did not want to pass a bigger jolt through the drivetrain. Also I purchased a brand new 1M with .3 miles on euro delivery. 4 years after I purchased a used one with 9k miles. I drove both great distances with AC on. The used one I drove in August with 4 people in the car and AC on from Toronto Canada to San Diego California through hot monument valley, Utah New Mexico and 112 degree Arizona. I have never experienced this in either 1Ms. I have experienced it with older cars that are not running at their prime. I don't want to guess too much but perhaps injectors are not at their peak or plugs might be off a bit or something like that. We are supposed to run BMW system cleaners in these cars pretty regularly due to direct injection so it's a longshot but try buying a couple of bottles and see if it runs better under the AC load and keep us advised. Again I know you gave up an m3 for the 1M so hate to see you having weirdness. Also find another 1M owner near you and have him drive your car and you drive his to compare. My money is that the other car won't do it. If you are in SoCal let me know.
Best wishes

[nachob]

Originally Posted by nachob

Sorry you're having this issue and all of the people replying are great resources on here. I have done CDV deletes on two previous e46 BMWs and they made a difference but I have NOT done it on either of my two 1Ms. Unlike the e46 I felt the clutch engagement was great and very firm. Sometimes you even feel a thump which is normal so I did not want to pass a bigger jolt through the drivetrain. Also I purchased a brand new 1M with .3 miles on euro delivery. 4 years after I purchased a used one with 9k miles. I drove both great distances with AC on. The used one I drove in August with 4 people in the car and AC on from Toronto Canada to San Diego California through hot monument valley, Utah New Mexico and 112 degree Arizona. I have never experienced this in either 1Ms. I have experienced it with older cars that are not running at their prime. I don't want to guess too much but perhaps injectors are not at their peak or plugs might be off a bit or something like that. We are supposed to run BMW system cleaners in these cars pretty regularly due to direct injection so it's a longshot but try buying a couple of bottles and see if it runs better under the AC load and keep us advised. Again I know you gave up an m3 for the 1M so hate to see you having weirdness. Also find another 1M owner near you and have him drive your car and you drive his to compare. My money is that the other car won't do it. If you are in SoCal let me know.
Best wishes

I just saw that you're in Dallas area. I think M3 Adjuster is in your area. He might be willing to drive your car and give you a better idea of normal or not.

[Dackelone]

Back in January I bought an e39 540i 6 speed manual... for a few weeks I was wondering why the clutch action was so jerky in 1st/2nd gears. I then remembered the CDV delete mod. But I thought surely a 15 year old car(w/150K miles)... that someone would have deleted the cdv by then. Nope. On my next oil change I deleted it... I've been so happy.

[Fahrvergnügen]

Originally Posted by CarJunkie

The CDV can be modified on the spot with a small punch. The valve restrictor is metal and sits within the housing, and can be punched out easily. Then replace the empty valve housuing and voila. Very easy DIY also.

Thanks, I am just having trouble understanding the value that places like Zeckhausen add since it seems like all you need to do is puck the restrictor plate out.

[Fahrvergnügen]

Originally Posted by nachob

Sorry you're having this issue and all of the people replying are great resources on here. I have done CDV deletes on two previous e46 BMWs and they made a difference but I have NOT done it on either of my two 1Ms. Unlike the e46 I felt the clutch engagement was great and very firm. Sometimes you even feel a thump which is normal so I did not want to pass a bigger jolt through the drivetrain. Also I purchased a brand new 1M with .3 miles on euro delivery. 4 years after I purchased a used one with 9k miles. I drove both great distances with AC on. The used one I drove in August with 4 people in the car and AC on from Toronto Canada to San Diego California through hot monument valley, Utah New Mexico and 112 degree Arizona. I have never experienced this in either 1Ms. I have experienced it with older cars that are not running at their prime. I don't want to guess too much but perhaps injectors are not at their peak or plugs might be off a bit or something like that. We are supposed to run BMW system cleaners in these cars pretty regularly due to direct injection so it's a longshot but try buying a couple of bottles and see if it runs better under the AC load and keep us advised. Again I know you gave up an m3 for the 1M so hate to see you having weirdness. Also find another 1M owner near you and have him drive your car and you drive his to compare. My money is that the other car won't do it. If you are in SoCal let me know.
Best wishes

Adding some Techron through today and possibly the CDV mod later this week. Will keep you posted.

[CarJunkie]

Originally Posted by Fahrvergnügen

Thanks, I am just having trouble understanding the value that places like Zeckhausen add since it seems like all you need to do is puck the restrictor plate out.

Maybe none? :

[OneM]

I put Caltex Techron in once ..and a week later ended up changing all plugs & coil packs. Symtoms were hesitation n bogging