Continuation from an earlier thread: turns out that adjusting the cables wasn't the whole fix. When I later hooked up the laptop, I learned that I was still only getting 88% throttle. A lot better than <50%, but not enough! Some more adjusting there got me to 95%, but it seems I've got something weird going on with that last 5%.

On a traction-control-equipped F-body (TCS on a Firebird, ASR on a Camaro, RPO code NW9), there are three throttle cables:
1. One from the pedal to the pulley on top of the traction control servo (I'll call this the "pedal cable")
2. One from the cruise control servo to that same pulley ("cruise cable")
3. One from that pulley to the throttle body ("throttle cable")

The throttle and cruise cables have adjusters on them, and I adjusted those in the previous thread. The adjustment procedure is:
1. Slide the clip up
2. Extend the sheath until the throttle begins to open
3. Let it relax until the throttle closes
4. Snap the clip back down

As noted above, I adjusted them again, more carefully this time, and got from 88% to 95%. This is definitely as much as I'm going to get out of these.

The pedal cable has no such adjuster; it's just a fixed length. I've confirmed in the factory service manual: in the accelerator cable replacement procedure, there is no mention of any adjustment, nor is any adjuster visible in the corresponding parts diagram (it's the cable labeled "1"), whereas the adjuster is plainly visible on the throttle cable ("23"):


I've adjusted the cruise and throttle cables correctly, but the pedal cable is about 1-1.5" too long, and as such I am unable to get to wide open throttle by pressing the pedal to the floor.

To prove my theory, I artificially "shortened" the cable by taking up some of the slack with a spring clamp. With this, I was able to observe the full 0-100% range in HPTuners. This is obviously not viable even as a short-term solution!

In the absence of an adjuster, I've come up with three possible explanations for this:
1. The cable has stretched.
2. The accelerator pedal arm (a thick steel rod) is bent out of its correct shape.
3. The clip that attaches the cable to the firewall has slid along the sheath.

None of these seem even remotely likely, but if I were to bet, I'm going with #3. No idea how or when that might have happened; maybe it had something to do with the removal and replacement of the engine.

Anyway, I need to fix this. I can think of three ways to do it:
1. Re-terminate the cable.
2. Bend the pedal arm more.
3. Slide the firewall clip back along the cable to its correct position.

None of these strike me as particularly good ideas. I was really hoping to avoid re-terminating any throttle cables, as the factory ends have always seemed much more robust than what a DIYer can manage. The third in particular gives me pause. I don't expect to be able to move it, and if I can, what's to stop it from sliding back again?

At this point, re-terminating the throttle cable (probably at the pedal end) seems to be my least-bad idea.

I'd love any suggestions you might have!

 

I'm just a bit confused, has something new happened since this post:

https://ls1tech.com/forums/generatio...l#post20531080

...or was it not really "fixed" in the first place? Just trying to understand if this is a new issue or not.

 

It's what's left of that issue. As I noted, there are three cables. The result of that thread was that I adjusted the other two, which got me to 88% throttle opening via the pedal. It was enough better than before that it looked like it was opening all the way, but I later hooked up the laptop and saw that it wasn't.

Good call though; I'll edit to clarify.

 

Seems like this guy had roughly the same problem: https://ls1tech.com/forums/generatio...ble-slack.html

His was a non-cruise, non-TCS car, but apparently his stock cable (the one that goes from the pedal to the TB) had stretched more than half an inch. I guess maybe mine (pedal to TCS module) is stretched too? I'm going to try ordering a replacement cable and see if it's shorter.

 

Did you find you're problem? I have the same issue with mine. I can get 90%+ but sometimes the throttle don't close perfectly because I adjust it too tight to get more opening.

 

I managed to get it up to 95%, but still not full WOT. The Speed Engineering throttle body is posing some somewhat-expected tuning challenges, and I am going to switch to something better (probably Nick Williams) before I spend more time on it.

 

I may had the problem of not being full wot with my last TB but not being fully rest on the ajustement screw is new with the 102mm chinese TB. I figure out by opening a little bit the hole where the cable hook I was able to rest it on the screw and get 97% at wot. This is what it was missing in the cable adjustment to get close. For the tuning, I'll know this week at the dyno.

 

I’m having trouble understanding how opening up that hole allowed the throttle to open farther. Seems like it would have done the opposite?!

 

If you have prop something to hold the gas pedal down all the way and then push downward slightly on the cable between the throttle linkage and the cable bracket, do you get 100% throttle then? I’m wondering if the angle of that bracket is too high

 

Yes, it's the opposite bit it's what Ineeded. When the cable is hook on this hole on the TB I'm able to get full opening, like 97% but when a release the pedal, I'm at like 1% opening. The adjustment is the max on the cable so I'm unable to get it closed completely on the screw. By opening the hole, I was able to get it sit on the screw and adjust my opening at idle.