2002 325I Gas Pedal, final push to floor clicks in

Just a courious question. Right before my gas pedal hits the floor, (pushed all the way down) it sort of clicks down and then rests against the floor. Is this normal and what would the reasoning be behind this design? Thanks. Scott

Should be in the manual, but that's the "kick down" button that initiates the "passing gear" with cars equipped with automatic transmission.

This "gear-down" button is fully described in The Fine Manual , it tells your Steptronic tranny to downshift (if you are not in Manual Mode) to get the engine's RPMs up -- for passing and such.

It's a European thing!

Originally Posted by Test_Engineer

It's a European thing!

It's an AT thing!

The first time I drove an AT DBW E46 at WOT, I wondered WTF this was, too. My car doesn't have it, of course.

It's there because you're missing a pedal.

MB has the same setup I believe. I've owned manual versions of C-Class and now my 330i, but I have a question about the reason for the kickdown switch. I've driven probably dozens of other manufacturer's automatics and I've never seen a physical switch under the accelerator. They all downshift as necessary with partial throttle depression, and I'm sure MB's and BMW's do this as well. I mean, you don't have to floor the accelerator to get a 4-3 downshift at moderate speeds, right? So, why the "extra" switch for WOT? Is it to force the lowest gear possible at the current rpm? It still seems odd that they actually place a switch under the accelerator rather than have some other sensor mechanism, especially with DBW.

I always had the impression that this switch, once activated, also delayed the upshift until maximum RPM's had been reached. Then again, maybe it's just the effect of hard acceleration that does this. I dunno, it' just what it feels like to me, even if my Steptronic isn't in "sport" mode.

--J.

I used to have an 1995 Volvo 850 AT...it had a similar switch which caused the A/C compressor clutch to disengage if it was on...putting a little less parasitic loss on the engine.

Then again, looking at OBD-II data from that car the TB never got above 89% open...

Originally Posted by JonathanIT

I always had the impression that this switch, once activated, also delayed the upshift until maximum RPM's had been reached. Then again, maybe it's just the effect of hard acceleration that does this. I dunno, it' just what it feels like to me, even if my Steptronic isn't in "sport" mode.

Kick Down Switch:
When the throttle pedal is pressed fully to the floor, the kick down switch closes providing a ground signal to the GS 20. The GS 20 recognizes the ground as a request to provide an immediate down shift and to switch to the AGS sport mode shifting program.

Originally Posted by markl53

I mean, you don't have to floor the accelerator to get a 4-3 downshift at moderate speeds, right? So, why the "extra" switch for WOT? Is it to force the lowest gear possible at the current rpm?

Subsitute "road speed" for RPM and you have it right. It'll downshift all the way to 1st if the redline (6,500) allows.

LOL (at myself).

I experienced this when making an over-taking manoeuver (passing a bus) with traffic coming in the other direction, that was moving slightly faster than I predicted.

At first, I thought that the "kick down" - from 5th gear - and sudden increase in speed + RPM, was caused by my right calf muscles cramping as I depressed the accelerator pedal to the floor. This was followed by a strange taste of metal in my mouth, once the over-taking succeeded, and no one was killed in a head-on collision.

That was the first time that my POS E39 has seen something over 6200 RPM.

And yes, I usually drive like your grandmother, on a sunny Sunday afternoon, on her way home from church.





.

Originally Posted by Patrick 520iAT

LOL (at myself).

I experienced this when making an over-taking manoeuver (passing a bus) with traffic coming in the other direction, that was moving slightly faster than I predicted.

At first, I thought that the "kick down" - from 5th gear - and sudden increase in speed + RPM, was caused by my right calf muscles cramping as I depressed the accelerator pedal to the floor. This was followed by a strange taste of metal in my mouth, once the over-taking succeeded, and no one was killed in a head-on collision.

That was the first time that my POS E39 has seen something over 6200 RPM.

And yes, I usually drive like your grandmother, on a sunny Sunday afternoon, on her way home from church.

OK, here's an embarrassing story from my teen years. My first car (lucky me), 1970 Dodge Challenger w/ a nice 340 cu.in. V8 and auto trans. I was 17. All the cars I had driven before would pretty much downshift under part throttle when desired. Turns out Dodge back then needed full throttle to downshift but I didn't know. The car was still pretty new and I hadn't tested at full throttle. I took it to the dealer and complained it wouldn't downshift. The tech drove the car with me and a friend and once on the road floored it. Well, to say the least, the damn thing downshifted and took off like a rocket. My friend and I just smiled big and said, "oh I see"!

Originally Posted by markl53

OK, here's an embarrassing story from my teen years. My first car (lucky me), 1970 Dodge Challenger w/ a nice 340 cu.in. V8 and auto trans. I was 17. All the cars I had driven before would pretty much downshift under part throttle when desired. Turns out Dodge back then needed full throttle to downshift but I didn't know. The car was still pretty new and I hadn't tested at full throttle. I took it to the dealer and complained it wouldn't downshift. The tech drove the car with me and a friend and once on the road floored it. Well, to say the least, the damn thing downshifted and took off like a rocket. My friend and I just smiled big and said, "oh I see"!

That's the funny thing. It seems that most people don't realize that their cars can go past 3000 RPMs. I'm not just talking BMW owners, I mean everyone. Usually if you try to push the car past 3K rpms or maybe it's 4K, it downshifts, and the engine makes a "funny" noise. The car starts moving fast, but maybe people think they're hurting their cars? Anyway a lot of Japanese cars get labelled as slow, simply because people don't really know how to drive them.

Originally Posted by scotthansford

Just a courious question. Right before my gas pedal hits the floor, (pushed all the way down) it sort of clicks down and then rests against the floor. Is this normal and what would the reasoning be behind this design? Thanks. Scott

The purpose of this mechanical detent is to simulate a feel of the TV cable from the days when gas pedal was connected to throttle body by cable. It is there because majority of the people are used to getting this feel from older systems. There is no electrical switch and it serves no purpose other then that. The kick down points are calibrated in the power train controller and are not constant like with cable systems. Some newer contactless pedal designs, Volvo for example, allow each pedal to be calibrated at the EOL point to program start/stop points and output curves.

Regards, Igor

Originally Posted by ebforce

The purpose of this mechanical detent is to simulate a feel of the TV cable from the days when gas pedal was connected to throttle body by cable. It is there because majority of the people are used to getting this feel from older systems. There is no electrical switch and it serves no purpose other then that. The kick down points are calibrated in the power train controller and are not constant like with cable systems. Some newer contactless pedal designs, Volvo for example, allow each pedal to be calibrated at the EOL point to program start/stop points and output curves.

No... well, highly doubt it. Manual transmission BMWs don't have a kickdown button, just those with Steptronic.

The technical guide for the E46 explains:

Kick Down Switch
When the throttle pedal is pressed fully to the floor, the kick down switch closes providing a ground signal to the GS 20. The GS 20 recognizes the ground as a request to provide an immediate down shift and to switch to the AGS sport mode shifting program.

From experience behind a Steptronic, hitting the kickdown will drop as many gears as possible instead of just one (could drop from 5th to 2nd).