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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Mon, Apr-16-2018, 04:52:33 PM   #1
ClutchKickChris
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Default Throttle Pedal Sticky, "Stiction"

Guys, my DBW throttle pedal has this terrible "sticking" or "stiction" problem. Gets worse in warmer/more humid weather lately.

Modulating it lightly up/down, like when you're on the highway, is incredibly difficult. It sticks and jumps in small increments.

I bought the 5-point security torx bit and opened it to inspect it. Everything looked fine inside, except they're all plastic parts that rub together. I cleaned and re-lubricated with pure silicone oil, re-assembled and although it's a bit better it's still far from what I'd deem acceptable.

My wifes E70 X5 has the same or very similar pedal and it's soo smooth in comparison its crazy.

Has anyone found a way to get these things to move smoother? If not I'm considering to buy a new one which I'd really like to avoid. Is there an updated unit perhaps?

I took some pictures of the inside if anyone's curious.
Attached Images
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File Type: jpg 20180314_190647 (Medium).jpg (185.4 KB, 16 views)
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Last edited by ClutchKickChris; Mon, Apr-16-2018 at 04:56:01 PM.
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Old Wed, Apr-18-2018, 05:56:27 PM   #2
patriot dude
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Default Re: Throttle Pedal Sticky, "Stiction"

I don't have the answer, but I do have the same issue. I also have noticed may gas pedal feeling exactly as you describe. Since I don't drive it much I've never taken the time to dig into it like you have. It does feel like plastic on plastic friction and I would have expected silicone to do the trick. Aerosol white lithium grease might also be helpful, it sprays thin and then thickens up once the solvent evaporates away. CRC makes a good one.
I've owned quite a few different vehicles, german, japanese, swedish, and good ole USA. This is the first car I've had with this pedal feel.
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Old Wed, Apr-18-2018, 06:09:11 PM   #3
Braymond141
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Default Re: Throttle Pedal Sticky, "Stiction"

Try to rebuild it and “lube” it with graphite powder (unless there is already grease in there fron the factory). I’ve never had an issue with these pedals. Our X3 has 250k miles on the original.

The pedal fulcrum is just plastic that is creased to allow for movement. If this is torn at all it will add tilt to the pedal when used. Common failure on the E36.
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Old Wed, Apr-18-2018, 06:53:47 PM   #4
terraphantm
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Default Re: Throttle Pedal Sticky, "Stiction"

What year is your M3? I recall there being a SIB early on for the E46 in general for a sticky pedal. I think the fix was to just replace the thing.
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Old Wed, Apr-18-2018, 08:12:00 PM   #5
ClutchKickChris
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Default Re: Throttle Pedal Sticky, "Stiction"

Hey dudes, so last night I pulled the pedal apart one more time and actually was able to fix this!

My theory/test was if that the tension springs have become weak over 12+ years perhaps adding tension back to them would prevent the sticking.
The spring tensioner design is actually pretty clever, it adds friction to the rotating surfaces as pedal travel increases. It may seem that adding more spring pressure and thus friction would be counter-productive but it totally works for plastic stiction.


To add tension to the springs:

1.
Here's the stock unmodified spring and "bead"


I cut/modified RC ball links to use them as plastic spaces. I then cut then down one side with an x-acto knife. You can use many other alternates for this.


2.
Add these spacers in place between the crimp end and "bead".


3.
Added heatshrink.


4.
Did the same for the opposite side, and reinstalled everything. Here's how the springs sit now with a bit more tension pre-applied to them.



With this extra tension there is zero sticking at all when actuated. The car is easier to drive now.
Attached Images
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Last edited by ClutchKickChris; Wed, Apr-18-2018 at 08:15:05 PM.
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Old Thu, Apr-19-2018, 01:20:06 AM   #6
mrgizmo04
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Default Re: Throttle Pedal Sticky, "Stiction"

That's a cool diy fix

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Discussing Throttle Pedal Sticky, "Stiction" in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)