Sloppy/stiff throttle pedal

[K Fox]

Hooray for my first DIY!!! OK, I know there are things on all of our cars that we hate. Things that we think will be tough, or take too long to fix ourselves so we put them off. Isn't it funny how on the end some of those 'hard' jobs end up being easy, and far more fulfilling when we're done? This is one of them for me - fixing my throttle issues turned my 540i6 into a whole new car.

Background - I had a slight delay in my throttle applications. I pressed the pedal and it seemed to hesitate a bit before the engine responded. I figured that the throttle cable itself was getting old and sticky so I ordered a new one at the dealership. But in finding a thread someone else had wrote on the process, I started getting waffley on doing it - too much work for something that might not work. Once I got in there though, I found that my problem wasn't the cable, but the linkage inside the car that pulls it. I'll let the pics do the talking now, and describe the job.

The first step which will make things much easier is to disconnect the throttle cable from the throttle body. Just pop the black plastic holder out of it's slot, then remove the holder from the cable - one side is split for this.



Now for the fun part. This is what I was greeted with when I got the lower cover off - dust and dirt on everything, and a broken bushing on the linkage itself (under that arrowed clip). On mine, that plastic bushing broke completely apart and fell out, allowing the bar to flop around, which was ultimately the cause of the slack/delay in my throttle. There are 2 of these bushings on the bar, and they are actually the retention mechanism for holding it in place as they are a tight fit in the channels on the pedal box.



It's probably easiest at this point to remove the cable from the linkage - with all the slack from unhooking it in the engine bay, just pull the linkage bar towards you and work the end thru the grommet. The walkthru I found before trying this says to pull the end of the cable through and remove the grommet, but mine was very tough to get out, and when I tried just prying the cable end through it worked easily.



Now for the bushings (what's left of them, anyway). After popping the retaining clip off, all you have to do is slide

them to the right to remove them - they have a tall lip on one side so you can't slide them the wrong direction (not that it really matters if you're replacing them). I was replacing both bushings as they're $1.60 at the dealership, though they didn't have them in stock and had to order them, so call ahead to save a trip (part # 35411154172). Also, that retaining clip keeps the bar from sliding around left and right - removing it allows you to slide the bar to get more room when removing the bushings.



Now the bar is loose, but it's still held in at 2 points - the throttle pedal and the spring. The spring is next, just unhook the top 'hook', then pull the bottom arm straight out towards the rear of the car - there's a small kink on the bottom if it to make sure it can't come undone in normal use (this was tricky until I figured out it had that kink - forgot to take a pic, sorry).



The pedal is easy to deal with at this point - there is a channel on the pedal for a tab in the bar - pics show details, just line them up and the bar slides right out.




Now the bar is out, so you can slide off the spring and any bushings still left on it and clean the bar and the spring really well. My bar was pretty chewed up from being used with no bushing at all, but in the end it seems OK - I just made sure to lube everything well with heavy grease.




At this point if all you are doing is replacing the bushings, then installation is the reverse of removal (LOL - I've always wanted to say that...). The trickiest part is getting the spring hooked up right, but just get the bottom part in first, then use pliers and pull the top hook back into place. But since you're already this deep, why not replace the cable too? Read on for the few steps it takes for that.

To replace the throttle cable on my 540, it was pretty simple all in all. It looks intimidating when you try to trace it's route in the engine bay...



And while it goes behind the heater valves, it's not that bad.




With access to the cable in the engine bay accomplished, the hardest part is now at hand - you need to get the plastic clip through the firewall from inside the car. After much fussing I found that needlenose vice-grips were the weapon of choice for this battle, and worked quite well, really. Just clamp down on the clip top and bottom, then push outwards at the same time (which is where the vice grips shined - you can lock them and then push easily without having to hold tightly to compress the ears on the clip). Once loose the clip will pop right through the firewall, and the rest is easy.



At this point, the cable will come out without much fuss, and again, reassembly is the reverse of removal, though it's a lot easier. Just snap the cable clip into the firewall after routing it behind the heater valves, then put the valves back where they belong. reconnect the cable to the linkage in the car, and then to the throttle body.

This is what everything looked like after reassembly in the car.





I thought this was going to be a lot harder than it actually was. The end results are well worth even the harder job I was expecting - this is truly a big deal. My throttle is now completely smooth, and there's no delay whatsoever in engine response. Also, I had always thought that my throttle was too stiff, and this greatly reduced the effort of the pedal. Had I known about these bushings and their issues I would have done this months ago, but I had no idea until I got under that cover and looked. Now that it's fixed, I can tell I need new engine mounts as there is a palpable thump when going from coasting to power, but I had previously attributed that to the throttle. Next up is those engine mounts - just need to get them here. Hope this helps someone - I'll bet this is a more common problem than we all think.

Fox

[gdaE34]

Awesome! Nice work. Just another thing to add to the list.

[K Fox]

Awesome! Nice work. Just another thing to add to the list.

Hopefully it goes in the DIY section - if it's not worthy then I'll tweak it till it is. Now if I could just find a way to properly demonstrate the before and after feeling of the pedal, it would be perfect. I'll have to ponder on this...

Fox

[AZDinanE34]

Great DIY K Fox! I had the same thing, a sticky throttle cable where after pushing the pedal down would take alittle bit longer to come back up making my car rev much more at idle until the motor was warmed up. I purchased my cable and just have to install it but these pics and diy helpout greatly. I'll prolly add to your thread on the install for the M50, thanks again!

[K Fox]

Great DIY K Fox! I had the same thing, a sticky throttle cable where after pushing the pedal down would take alittle bit longer to come back up making my car rev much more at idle until the motor was warmed up. I purchased my cable and just have to install it but these pics and diy helpout greatly. I'll prolly add to your thread on the install for the M50, thanks again!

You're welcome! And any changes between the 525 and my 540 are very welcome, just post them up!

Fox

[gcb]

Awesome pics and info!

I have some play on that cable and a )!(#@$! squeak noise when starting to press the pedal... i will see if I can beat AZDinanE34 with pics for the M50

[attack eagle]

Looks great, great pics.
Should be DIY'd imo.

[jehu]

I did mine in a parking lot in about a half hour.. I never looked at the pedal arm bushings though.. New 540 seems fine but now I know soemthing else for which to look. I was likewise blown away at the night and day difference in the ease of depressing the pedal after the new cable went in.. well yah it was like Butta..

[3axap]

Just went through this exact thing with my 535i. The bushings were MIA. I went full retard and ordered only one bushing instead of two. Ended up manufacturing a bushing from a piece of hose w/ a matching ID. Seems to be working ok for now. Pedal feel is definitely much improved and way smoother.

[jbondbmw]

Is it true that if a 540i has ASC, it has EML, and then doesn't have a throttle cable? Or am I way off base here?

[jehu]

Is it true that if a 540i has ASC, it has EML, and then doesn't have a throttle cable? Or am I way off base here?

Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaay
off base...

[jbondbmw]

Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaay
off base...

Ok, sorry.

[jehu]

Ever open your hood?lol..

[K Fox]

Ever open your hood?lol..

Some of the 540's out there have engine covers. Actually, I took mine off as I like the look of the runners on the manifold. But to be fair, the stock engine cover does hide the cable very well...

Fox (appreciating the comments and compliments)

[jbondbmw]

I have never taken the plastic engine cover off. I am doing spark plugs soon, so I'll have to do it then.

[GIANUCCI E30]

dumb question time. I haven't took a look down there on my 535i. But can anyone verify if it's possibly the same procedure?

[gcb]

If you are clueless, like me, on how to remove the panels, this is great http://forums.bimmerforums.com/forum...5&postcount=69

(also, a great thing to do while you are down there)

[raceyBMW]

Why isn't this in the DIY section? Awesome write-up!

[K Fox]

dumb question time. I haven't took a look down there on my 535i. But can anyone verify if it's possibly the same procedure?

While stranger things have popped up as model differences before, I'm willing to bet that all E34's have the same throttle pedal layout. With that said, I have no way of being sure as I don't have (or have access to) a 535. Maybe someone with one will chime in???

Why isn't this in the DIY section? Awesome write-up!

Thank you. And tell the mods to move it if it's deemed DIY worthy.

Fox

[johnnye23]

Great writeup!!! I just did all this on my Touring and the throttle was night and Day better !

[jgdynamics]

best mod and best write up ever. everything was exactly the way you wrote it and pictured it. Thanks for the instructions, the difference, was indeed, night and day!

[gcb]

Started doing this as a 'breather' project while trying to fix my blower motor. just something to actually DO instead of TEST :/

don't think this DIY needs any improvement, so i will just put a pic that gives a better view of the sizes of the components... don't know why but i was expecting that axle to go over most of the floor width

ok, so here's the pic. don't mind the lack of one pedal...

[Sherman]

This should really be in the DIY section. I completely forgot about this, but mine's in the same condition.

[NedMW]

So how do you get the accel. pedal back ON the shaft?

[Analog]

If it takes any more motivation.....

REPLACE YOUR BUSHINGS AND THROTTLE CABLE!


I did this yesterday, and I cannot describe how much more enjoyable driving the car is.

The pedal is light and smooth. Engine response is absolutely on point.

Rev-match downshifting is twice as easy now.

After 197,000 miles, my throttle cable was a 1/2" longer than the new one, and I only had 1 pedal bushing!


Thanks for the DIY K Fox!


For the plastic clip on the firewall, I used a long screwdriver and a 5lb hammer and knocked it out towards the engine. Took 4 or 5 taps.