Big problem here guys!!!

I adjusted my cable about 3 notches originally. After a while the car started to feel a bit sluggish, thought I might adjust the cable 1 more notch. As of now my cable is adjusted (7)!!! Notches!!! It felt great but now it’s back to feeling so so again. I believe that adjusting the cable is only stretching it more and more...
Any thoughts on how I was able to adjust it 7 notches?

 

Probably because (as I posted numerous times before) the basic mechanism resets the cable to a "correct" position. In the JTIS, the step that does the actual adjustment is the final step where you floor the pedal (with the engine NOT running, of course) and that sets the final position. With my previous car, there was a similar adjusting mechanism and you could initially position the cable anywhere you like (even tension it too much so that the throttle blades were open when the pedal was being pressed) but the final step of pressing the pedal re-adjusts the cable to the right position. The perceived "performance gains" with this adjustment are only due to the fact that you are opening the throttle body quicker (assuming the original adjustment was way too slack) but once you floor the pedal, the mechanism resets to a "correct" position. once again.

Doug

 

Yes, they were - and how much was that gas? DaleD

 

So in short this whole throttle cable adjustment is a bunch of B/S?

 

Bingo! Give that man a cigar! If the cable had too much slack to begin with, then the adjustment is necessary so that the throttle blade opens all the way once the pedal is floored. Any other adjustment beyond that is wasted and will eventually reset.

Doug

 

Well, I wouldn't be too quick to say it's all a bunch of BS. In my car, the cable was indeed too slack and the throttle blade did not fully open. The adjustment made a ton of difference. I adjusted it about a month ago (and it has been floored many times since then) and it's still just as responsive as if I had done it yesterday. In this case, maybe there was so much slack that the "auto-adjust" feature couldn't get it to the correct position without a human bringing it into the ballpark by doing the manual re-adjustment first. Anyway, it's far better than it was and seems to be staying that way. (I think I'm pretty much saying what Doug did in the above posting.)

Best regards,

 

Yes you are. If the cable is too slack, AN ADJUSTMENT IS DEFINITELY NEEDED. Any further adjustment to over-tighten the cable is a waste.

Doug

 

Of course it isn't BS, the more slack in the cable the less you can turn the pedal position meter and obviously you will not reach 100% pedal position then, as simple as that. Not sure what the problem is with Miami XKR, probably best to check the cable mechanism.

 

I completely agree. Prior to the adjustment my car seemed sluggish and unresponsive. After the adjustment it felt like I had rockets strapped in the trunk.

And having opened up the mechanism and made the adjustment, I don't see where this alleged auto-adjustment mechanism is. I've looked at both ends of the cable, both down at the gas pedal and up at the position sensor. I don't see anything that could function as an auto-adjuster. Until someone can show us some type of Jaguar documentation, or a picture/video of the auto-adjustment in progress, I'm going to assume it's a mythical feature that doesn't exist.

 

Indeed there is NO auto adjustment, the TB has one but that has nothing to do with the pedal setup/pedal positioning meter.

 

It is not an auto adjustment but a RE-adjustment should you over-tighten the cable. For the umpteenth time this is why the final adjustment step in the JTIS is manually depressing the cable to the floor--NO MYTH.

If you need to be convinced then why not try moving the so-called adjustment notches to the very end where you have no notches remaining and then go through the final procedure of flooring the pedal and see if the RE-adjustment occurs.

Doug

 

No idea what a RE-adjustment is, but the JTIS procedure seems pretty clear for 4.2 cars, it actually allows for a little slack (which is why they use the tool). The assumption is that the pedal when it hits the kickdown switch is also the max on the pedal positioning sensor, this is how you should lock it (otherwise you put the full load of the pedal onto the PPS housing. The setup of the 4.0 cars is slightly different.

 

I don't want to cause any arguments or anything but I think it is clear to see from this 2 things:
1) It is possible to adjust the cable and get back what power has been lost through slackness and drivers themselves auto adjusting to the slack.
2) It isn't a magic fix to make the car fly to the moon-Though I'm sure the majority of people who have done this (like myself) understand that it restores performance rather than gains it.

I'm sorry to say but most of the posts on this particular matter seem to be Seismic Guy saying the same thing over and over. People are bound to run into issues when doing these fixes, and in some cases may not initially understand what the fix does or can do. That is what the Forum is for, for other owners to help each other out with tips and advice, not for opinions to be enforced onto folk.

 

Sorry if it bothers you that I have have had to say the same thing over and over but misinformation about this "miracle performance improvement" was being given over and over.

Doug

 

How is it misinformation? H20boy even put his fancy OBDii tool on it and it showed his throttle wasn't fully opening. If I remember right his throttle was only 80-something percent open before the adjustment and 100% open afterwards. That seems like a pretty straightforward performance improvement to me. It was free and it gave me better results than a silly K&N air filter or removing the center muffler.

 

For the last time (hopefully) I am not disputing whether or not this will fix a mal-adjusted condition. But it is akin to having tires that are under-inflated and, hence, resulting in poor performance and poor gas mileage and then correctly inflating them to the right pressure. Or having one of your spark plugs loose or fouled and then replacing it with a good one (ditto for a bad spark plug wire). By addressing these things (under-inflated tires, bad spark plug, and yes a throttle cable that has so much slack that the throttle does not fully open), I would hardly say that these are performance improvements. They are merely routine maintenance to address deficiencies and loss of original performance. We wouldn't see a bunch of posts about how thrilled people were by finding "extra power" by correctly inflating their tires. But with the throttle cable issue in particular, it sounded like all sorts of folks were thinking that they had discovered some untapped source of "extra" power when all that was being done was an adjustment to regain the power that should have been there--and no more.

Doug

 

It all boils down to the fact that if you do the adjustment, you are assured it is properly adjusted. That being said, if you feel an improvement, great. If not, at least you know it is properly adjusted. I felt an improvement and am happy I did it.

 

Very well stated

Doug

 

Misread the RE_adjusting ;-), but that was not what I was speaking about, I thought we where discussing Miami XKRs issue, and the auto adjustment (/reset) you where speaking about.

This is part of the procedure, I think many will not follow the full procedure (otherwise they would also ask about the tool that is required).

The procedure assumes a tool in place to allow for a little slack as mentioned. Then it also assumes you have the spring bit that locks the cable is loose! Only then you can press the pedal to the floor for the right adjustment, and after that you need to set the cable.

So there must be somehting wrong, as once set you should not get slack again (after such a short period).

 

Not having the "special tool" is probably not a big deal as you can sensibly judge how much slack to build in to the adjustment. The last step of pressing the pedal to the floor is supposed to be done AFTER the cable retaining clip has been installed (see a pdf of the procedure from the JTIS that I posted way back when https://www.jaguarforums.com/forum/s...t=38663&page=3)

The curious thing is that the final step of slowly pressing the pedal all the way to the floor (per the JTIS "The accelerator cable must be adjusted by pressing the accelerator pedal. . .") is NOT done with the key on, so this must be some strictly mechanical adjustment that is happening.

To finally resolve what is going on it would be great if somebody was willing to disassemble the mechanism to which the cable attaches to see exactly what is happening during this last step.

Doug