Jeff928S4

Been having some bad auto shifts and plan on getting the car up on a hoist soon to do a fluid change/filter/vacuum check/maybe adjust that modulator thing very soon.

In the meantime, I saw a thread today about throttle cables;, so I went searching on Rennlist and discovered lots of info on the throttle linking, etc. Up until today, I had no clue there was a transmission cable amongst that group.

I have an 89' S4; my throttle cables look like this...




So, I went at it.


1. I unhooked the bowden cable.


2. I adjusted the "from pedal" cable by twisting the plastic nut by the firewall (removed air box to get better access). This cable was quite loose, as when I wiggled it, the metal piece it attaches to made a "cling" sound as it hit the other metal it appears it should rest upon. The metal plate it attaches to was not snug. *Note - my car idled around 450-550 and I always felt it lacked a "crispness" when first rolling. I adjusted this cable until it was snug and the metal plate was juuuuuust touching the other metal plate - no more "cling" if I wiggled the cable and the cable felt snug. I could push the cable towards the intake about an inch before the assembly moves, so it wasn't too tight I don't think.


3. I then adjusted the "to throttle" cable using the plastic nut. Following info I learned, I tighten it, then backed it off one turn at a time until I could hear the TPS click if I moved the throttle slightly. Got a nice click both ways - left it like that.


4. After doing this, I could feel by touch that the bowden cable was loose - when unhooked, one can easily pull the ball about a half-ball distance past where it is supposed to go. The metal adjuster won't turn freely anymore.


QUESTION - in doing some reading, I see some have snapped the bowden cable in an attempt to adjust it (holding the cable with vice grips and trying to turn the ball). What is my best plan of attack in getting this cable tighter (from the engine bay....for now)??? Do I do the vice grip thing and just be very gentle? The bowden cable adjuster is soaking as I type this.


5. I did not adjust the cruise cable much - just enough to snug it up like the "to pedal" cable (it also makes a "cling" when loose). *NOTE - I also found you can raise/lower the idle by adjusting the cruise cable, as it pulls back on the entire mechanism when tightened (thus raising the idle). Does this sound correct? Not that it is meant for this, but it is a side-effect.


So, after all was done, I started her up and she snapped to a start like never before. As soon as I hit the gas, there was an instant "jump" I never felt before. The "snap/pep/crispness" I always expected from a roll was finally there. I assume this was because of the "to pedal" adjustment.

Didn't really feel a difference in the transmission, but the extra pep seems to equal somewhat better shifts. Less "clunk" on downshifts.


Here is another thing - after making these adjustments (and making sure the cruise cable was not causing it), my idle is now around 900ish - just hovers under the 1000 line (or the 4th line). Before it would hover between the 2nd and 3rd line...closer to the 2nd line, which would put the idle at under 500. There was always a "stumble/hesitation" when applying the gas at first at the lower idle.

The idle stays at 900ish if I rev the car. Now thinking I may have made a bad adjustment (the idle seemed too high?? - I was so used to the lower idle), I simply took my foot and pulled outwards on the accelerator slightly, and BAM, the idle went back down to 500ish. Rev the car and it settles back at 900ish.

Is the cable too tight? Shouldn't the RPM drop until the pedal is allllll the way released, or does pulling the pedal outwards always cause a slight dip in RPM on all cars? As in, if the pedal is just left alone and it bounces back at settles at 900ish then leave it like that? Sorry if this is confusing - lol


So, that's about it......basically in summation.....

- How do I adjust the bowden cable with a stuck adjustor
- What should my idle be at normally and would pulling slightly outward on the accelerator cause an RPM drop or is the cable too tight?

Thanks all!

MainePorsche

No, no Jeff.
Your throttle cable must be the FIRST cable adjusted.

MrMerlin left this on one of my postings.


"SO you must start with the throttle plate cable, this is the cable that goes around the wheel.

first once the quadrant is moved slightly you should hear a click from the TPS,

SO adjust this cable so when the quadrant is moved slightly you get the click,
same for releasing the quadrant you should hear a click, this must also happen,
then fit the Bowden cable

NOTE if the throttle plate cable is loose it makes the bowden cable effectively too tight.
and visa versa.

a small change on the T plate cable changes the adjustment on the Bowden cable.

NOTE any adjustment you make to the throttle cable will affect the bowden cable adjustment,
and thus any of your adjustments will now have to be redone.

NOTE I am not talking about the gas pedal cable adjustment,
this should be done after the T plate and Bowden are fitted,,
then make sure you get full throttle operation with the pedal put to the floor.

Connect the Cruise control last with some slack in the cable"


Worked like a charm.

The order of cable adjustment is: Throttle, Bowden, Pedal, then Cruise.
Adjust the Bowden so that it is ball to the cup initially. Then when your 'done' with all four you will most likely have to re-adjust the Bowden, but this will be done to speed and shifting timing. We'll deal with that later. Get you throttle cable done RIGHT first.

westija

Check this to see if it helps

http://jenniskens.livedsl.nl/Technic...7/MyTip774.htm

And this:

http://jenniskens.livedsl.nl/Technic...1/MyTip162.htm

Jeff928S4

Does this work with my set-up? I don't have "wheel", do I?

Also, I'm failing to see how loosening the throttle cable tightens the bowden cable? They both seem to be on the same metal plate. When I loosened the throttle cable all the way off, the bowden cable didn't seem any more tight. ???

Jeff928S4

Thanks!

Sadly, that appear to be for a 87'.....and a 5-speed. The description of the set up sounds different than mine. He only mentions 3 cables and there is some pulley by the engine? I don't have that.

MainePorsche

Here is a pic of the wheel that the throttle cable uses.
Tightening the throttle cable will loosen the kickdown (Bowden) cable. Like my organic chemistry professor once said, "you have to see it in your mind's eye".

Bill Ball

As to the high idle - if pulling back on the pedal lowers the idle, then the cable/pedal/throttle linkage is sticking somewhere. Now, I've never had to lube these parts, but who knows, maybe you need to try squirting some WD40 (or some other superlight lube/cleaner that will not gum up the cable) onto the cable and/or pivot points. You could put a tiny amount more slack in the throttle cable and see if that helps too. You have demonstrated that the high idle is from the throttle plate not returning and seating.

The cruise cable MUST be LOOSE with a good amount of slack.

MainePorsche

Yes, you may be 'sticking' somewhere.
Yes, your cruise cable must have slack in it.
But what is undeniable, your THROTTLE CABLE MUST BE THE ONE SET FIRST. All others are set to this.

Jeff928S4

This wheel is located under the air box towards the drivers side, yes?

I'm going to re-adjust tonight....starting with the throttle cable.

I think the "to pedal" cable is too tight, as I am getting a fluctuating idle. I assume that the idle should be where the car idles when the "to pedal" cable is as loose as it gets (0 pedal input).

I'm going to set the throttle, then back off the "to pedal" cable all the way and adjust it until it tight AND the idle doesn't change. Cruise I will loosen a tad also.

As for the bowden cable, I'm just going to assume that my only option to unstick the adjustor is to vice-grip it and work the ball end till it turns.


....I will say, the throttle response/crispness of the car now is AMAZING - like driving a completely different car!

GregBBRD

OK guys. Let me see if I can help.

Disconnect the kickdown cable.

Disconnect the throttle cable.

Have someone push down on the throttle pedal to full throttle....without hitting the "full throttle" kickdown switch, on the inside of the car. The "compression" spring, on that cable, right at the throttle assembly, should not compress. Adjust this cable, at the firewall adjuster, until the compression spring is just ready to compress. This spring should only compress when the kickdown switch is activated. Adjust at the firewall, until these two things happen.

Hook-up the throttle cable to the engine.

Have someone push down on the gas pedal to almost full throttle.....don't have them "mash it"....just gently push down to right around full throttle. (Trying to not break that cable or do any damage, with this step.)

Push down on the short exposed portion of the actual cable, right at the throttle assembly, with your fingertip, and see if the cable has any "play' or movement. It should have some "play" if properly adjusted. If it doesn't, make it longer. If it has lots of play, make it shorter.

Now have your helper push the throttle to full throttle....without hitting the kickdown switch. Re-check the throttle cable with your fingertip. It should be tight and not have any play (the butterfly should be wide open.)

Now "mash" the throttle to the floor and active the full throttle switch. Nothing should change, outside....except the compression spring should compress. The compression spring is simply there so that the cable from the inside of the car doesn't break....when the kickdown switch is activated! You should have full throttle (butterfly opened completely) with or without the kickdown switch activated.

Now have someone hold the gas pedal on the floor. Pull on the kickdown cable as hard as you can...with your hand. Adjust the ball socket, until this cable snaps onto the ball.

Start the car. It should idle.

None of these adjustment should change your idle. If they do, there is something wrong....these cables have nothing to do with idle speed. Idle speed is set by a separate idle stop, at the butterfly, and then controlled by a separate idle stabilizer.

You can now go drive the car. You might need to increase or decrease the tension of the kickdown cable a couple of turns to get a perfect downshift at full throttle and "hold" that downshift until the proper rpms are reached......without hitting the kickdown switch! When you hit the kickdown switch, you should get a second downshift, up to 65-70mph.

Jeff928S4

I have a "kickdown switch" that was installed up by the drivers seat. I can flip the switch and the car is in kickdown mode without having to mash the pedal. Will this effect adjustment?

GregBBRD

No. You just don't have to worry about making sure the spring compresses at the bellcrank....past "normal" full throttle, where you would usually hit the kickdown switch.....you just have to worry about what is happening inside your transmission, when you flip that switch.

Jeff928S4

Even though I have the extra switch for kickdown, the car still kicks down when I floor it.........normal?


I tried last night with all my might to get that bowden cable adjustor to turn and it will not budge. Hopefully I can get it a tad tighter from the other end (or perhaps the tranny fluid/filter change will help).

I re-adjusted what I could starting at the throttle....then "to pedal". I have a steady idle around 650-700 now and the crispness is still there. Backed off the cruise a tad.

I am beginning to think the new crispness/better overall throttle response is not so much due to the "to pedal" adjustment as it was getting the throttle cable in the correct "click" position. I don't think it was adjusted correctly before I started all this.


BEFORE....

- Most of the time, I had to apply slight pedal when starting or the car would semi-flood and not start. If I turned the key and waited 5-6 seconds (to let the fuel pump push gas up), sometimes it would start right up. It didn't start well is the point - lol

- As I mentioned before, there would be a "stumble" when first applying throttle when in drive. I mean, the car drove fine, but until I was at a full roll, it felt like it was getting gas through pantyhose or something....it was just sluggish. From time to time, I drive the folks Intrepid and I always liked how crisp/fast and light the throttle response....no real power, but the car felt "jumpy" compared to the 928.

- When I would release the throttle while driving, the car would "burp".....in other words, it would feel like a rush of air or something followed the release of the pedal.....it made a noise - almost like the transmission geared down ever-so slightly, but there was no change in wheel speed - if any of that makes sense.

NOW....

- Car starts with no throttle input.
- Better idle
- Light/crisp throttle
- No more "burp" when off-throttle

I swear, it's night and day how the car drives. I was always impressed with the 928 on the highway, but felt it was sluggish from start till around 40klms/h. It felt very "heavy" from a roll. Now, it's VERY responsive from start. Before, if I floored the car once rolling, it would jump forward violently with lots of noise and gusto and felt like it wanted to go somewhere, but it just wasn't "right".

Last night I floored it at about 20-30 klms/h and the rear end spun out, it made a much louder noise and, overall, scared the **** out me. COMPLETELY different car now.

I recommend everyone to go out and check the adjustment on the throttle cable - it seems if that "click" isn't set up right, you may be losing lots of performance/joy in driving the car overall. Best adjustment I've made on the car so far!!!

...now, if I could just get that bowden cable adjustor to break free.

MainePorsche

Jeff,
Sounds like you've done well.
If you can't get the kickdown (Bowden) cable off the lever at the ball/cup union, you can do this -> Once your throttle, pedal, and cruise cables are 'adjusted' (and removed them from their ball/cup unions), remove the E cilp and the lever apparatus comes off in three pieces. You can then rotate the piece to loosen/tighten to what you need on the kickdown cable. The locking nut is 8 mm and a small 7 mm wrench will secure the the neck of the cup unit. It is a bit cumbersome, but it will work. Reassemble carefully and recheck the 'click' position of your throttle cable.

MainePorsche

There is no kickdown cable adjustment at the transmission end.