throttle response is sloppy, how to fix?

[Spiff325iS]

my throttle feels a little lazy, and its been like this ever since i got it a year ago. it all works perfect when im moving and such, its just right when i giv eit gas(if not applied smoothly), it sorta chugs down 100 rpms then go up just fine. I was wondering how i could make it a lot quicker(to respond, not drop or raise rpms).

[e30Matt]

Get rid of the AFM.

edit: And replace it with a MAF, NOT remove the AFM all together.

[clutterbucker]

mine does the same thing....punch the throttle then let off the pedal before the motor revs and it gets all kinds of confused....that's really my only gripe with this car...500-600 would fix that you're saying?

[bmwannabe]

yuh, not a cheap fix. Other than that try to fix the slack in your throttle cable.

[clutterbucker]

I don't think it has much to do with slack, because if I barely touch the throttle, it revs....but it's delayed. I think it really is one of those thing that needs some kind of expensive fuel/air/ciomputer modification. COme spring I'll probably man up and try the MAF out.

[MarkD]

Re: throttle response is sloppy, how to fix?

my throttle feels a little lazy, and its been like this ever since i got it a year ago. it all works perfect when im moving and such, its just right when i giv eit gas(if not applied smoothly), it sorta chugs down 100 rpms then go up just fine. I was wondering how i could make it a lot quicker(to respond, not drop or raise rpms).

How old is the O2 sensor? If it is old and has low output, the motor can end up running rich, and that can make it run as you describe. A performance hip can really help with the throttle response, but if the O2 sensor is old that should be changed also.

MarkD

[bmwannabe]

well i mean i have the delay that you speak of, and mines def not the cable. it was just a suggestion

[uofom3]

Throttle cable clips from the dealer might help, if they fit your throttle setup... here is a link to what they are:

http://www.e30m3performance.com/installs/installs-1/throttle_clips/clips1.htm

Have you changed your fuel filter? air filter? o2 sensor? all of these things slow that down.. my m3 still does it a bit, but it's just the AFM.. an MAF is an improvement.. but i can say that the m3 guys all swear ditching the AFM altogether is the way to go... and so did BMW motorsport... all of their race cars are AFM free... you can get a setup like Alpha-N for around 5-600 USD... but i'm not sure what cars they make maps for... the SS MAF kit is a much more easily tuneable solution...

[bmwman91]

The problem IS the AFM. When you rapidly blip the throttle, the AFM "trap door" opens and will have some momentum. When you let off the gas rapidly, the throttle plate shuts prettymuch immediately while the "trap door" will still be open because of the momentum of the incoming air and its own angular momentum. The ECU will see: throttle at fully shut, and AFM reading partially open and think WTF mate? That is the problem. To fix it, either swap to an AFM or just be a real enthusiast and go S-AFC (megasquirt, TEC-3, etc). Anyway, all of us E30 owners will be plagued by the erratic engine behaviours described above if we decide to pound the gas on & off below 1500RPM.

BTW, for what you get the SS MAF kit is waaaaay pricey. One is much better off with the MegaSquirt S-AFC that can run either Alpha-N or MAP+RPM+TPS

[e30Matt]

The problem IS the AFM. When you rapidly blip the throttle, the AFM "trap door" opens and will have some momentum. When you let off the gas rapidly, the throttle plate shuts prettymuch immediately while the "trap door" will still be open because of the momentum of the incoming air and its own angular momentum. The ECU will see: throttle at fully shut, and AFM reading partially open and think WTF mate? That is the problem. To fix it, either swap to an AFM or just be a real enthusiast and go S-AFC (megasquirt, TEC-3, etc). Anyway, all of us E30 owners will be plagued by the erratic engine behaviours described above if we decide to pound the gas on & off below 1500RPM.

BTW, for what you get the SS MAF kit is waaaaay pricey. One is much better off with the MegaSquirt S-AFC that can run either Alpha-N or MAP+RPM+TPS

S-AFC's made by Apex'i. :)

[Rob]

SAFC cant run a MAF can it? I mean I know it can, but can it handle the signal conversion necessary to run a MAF on a AFM based ecu?

[Spiff325iS]

so if i was to look for what i need to make it better, what would it be, i know you guys mentioned some things, but just a post on the actual product could help.


so, what you need to reduce lazyness of throttle is(you fill in space if you have info):

And you can get it here(you fill in space):

It will take about ____ to install.

thanks.

[uofom3]

maxx-alpha N... completely programable... ditches entire AFM assembly and once properly tuned will yield more horse power and throttle response than anything else mentioned here... removing the AFM is the ONLY way to remove the trap door and the poor air circulation setup.. this method operates based on your TPS readings.. i am not certina if this product is available for your car.. but you can click the send e-mail link here

http://www.s14.net/forums/member.php?s=&action=getinfo&userid=280

and he can let you know. This product is run on countless e30 m3's and is now being run on e36 m3's and virtually every high HP engine in both categories is running this setup (unless they have gone motec or other SAEMS). Some other setups may be easier to tune or make work right, but nothing will completely plug and play and ditch the AFM like this will. This is my next engine mod, hopefully next year... ditching the AFM makes the car feel totally different... especially the throttle reponse...