[x300] Kickdown switch adjustment WOT on V12 X305

This topic has been touched on regarding xj6’s but all I
could summarize was that the TPS needs to be adjusted to a
specific voltage when the kickdown switch is activated.
Is this different on the v12?

Heres my dilemma, I couldn’t help but notice that when I
pressed the throttle down to the kickdown switch, the
throttle lever position was at only about 65%-70%. I
verified the butterfly angle externally to be about that as
well. So cart before the horse, I adjusted the kickdown
switch by rotating it clockwise down about 2 and half to 3
turns until it bottomed out. Now the throttle is opening
about 90% and maybe 95% Floored (switch activated). There is
still 1/2 to 3/4 inch travel left before the hard stop on
the actual throttle mechanism and reaching what looks like
true 90 degree on the butterflies. About 80-85 degrees now.

Well the good news it seems is that ‘‘Puss’’ really growls now
and perceives to have more power. My guess would be more air
equals more power under heavy load. It still shifts just
under redline and will still downshift if ‘‘floored’’. So my
feeling is that this is good, Except I kept reading that the
kickdown switch is adjusted to give optimal transmission
response and since I didn’t fully mark this and don’t know
the technical tuning procedure, Is this as it should be?

My gut feeling says that more AIR at WOT is always better
and I shouldn’t worry about the transmission switch doing
its thing. But I don’t want to damage either engine or
transmission.

I don’t plan on pushing her hard at all. I tend to baby her
most of the time. I just tested the results 5 or 6 times and
it seemed like a definite improvement power wise, especially
engine growl.

Oh btw, my mileage is more around 13.8 mpg city and 17.5
highway.

Thanks for any input,

~Jason–
Jason Shaguar Midnight Blue X305 95 XJ12 SWB LHD Florida,Us
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In reply to a message from Jason X305 sent Mon 8 Jun 2009:

Hi Jason the JTIS says 90% for the 6, but the only reference
for the V12 is operates at max throttle, perhaps the rev
limiter stops you red-lining!

Maybe someone has tweaked it on a rolling road for max urge
and can supply a better view regard optimal response!–
The original message included these comments:

about 90% and maybe 95% Floored (switch activated). There is
and perceives to have more power. My guess would be more air
equals more power under heavy load. It still shifts just
under redline and will still downshift if ‘‘floored’’. So my
kickdown switch is adjusted to give optimal transmission
response and since I didn’t fully mark this and don’t know


Neil Bennett 1997 X300 3.2 Sport 69k miles Maldon UK
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In reply to a message from NEIL BENNETT sent Mon 8 Jun 2009:

G’day Gents,

I couldn’t find any info on the kickdown switch adjustment
procedure so I adjusted mine so that at full pedal travel the
throttle butterflies were fully open and the kickdown switch had
closed.

Having both throttle linkages adjusted correctly I found gives a
much better throttle response, more ooomph!

Regards,
Jeff Watson.
Sydney, Oz.
1995 V12 X305.–
Jeff Watson
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I have mine adjusted so that the switch is closed as soon as possible, which
means turning it anti-clockwise as far possible without inadvertently
preventing true WOT. Frankly I’d like an even earlier kick down but the
adjustment range won’t allow it unless true WOT is compromised.

It has been in the back of my mind as a future modification for some time
now :slight_smile:

Cheers
Doug Dwyer
Longview Washington USA
1995 XJRFrom: “Jeff Watson” watto700@exemail.com.au

I couldn’t find any info on the kickdown switch adjustment
procedure so I adjusted mine so that at full pedal travel the
throttle butterflies were fully open and the kickdown switch had
closed.

In reply to a message from Jeff Watson sent Mon 8 Jun 2009:

Greets!

OOMPH sounds good! Thanks neil for looking for the exact
spec or procedure.
So it seems logic prevails, WOT is just that!

Hmm now how do I get the kickdown switch to let me go all
the way? It seems bottomed out as far as adjusting it
downwardly in. Hopefully not a full throttle cable
adjustment. I took off the cable mount above the plastic cam
cover to remove it for doing the spark plugs and if I didn’t
get the locking screws exactly back right it gave me
‘‘traction fail’’ and ‘‘abs’’ warning lights. IT didnt have but
a 1/4 inch to be off on the exact distance post traction
control.

Getting both linkages sounds inviting, I did replace
temporarily the linkage plastic grommet pivot points for the
butterfly rod with 1/4 inch rubber grommets. There was
barely 1/4 of them left. I do plan to get the ‘‘oem plastic’’
ones asap and do hope they snap easily in.

Jeff you make me want 100% Butterfly action! haha :slight_smile: Wait
til the misses sees this.

~Jason–
The original message included these comments:

I couldn’t find any info on the kickdown switch adjustment
procedure so I adjusted mine so that at full pedal travel the
throttle butterflies were fully open and the kickdown switch had
closed.
Having both throttle linkages adjusted correctly I found gives a
much better throttle response, more ooomph!


Jason Shaguar Midnight Blue X305 95 XJ12 SWB LHD Florida,Us
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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In reply to a message from Doug Dwyer sent Mon 8 Jun 2009:

Somewhere I read about a modification by adding another foot
switch on the wheel well. I also Envision a toggle switch on
the J-gate knob. My hand tends to rest there anyways even
though I jut keep it in regular drive. I believe the switch
is a NO (normally open) wired in parallel to the footswitch.

I did find in the v-12 forum on how to adjust the throttle
linkage. The reference is off site but has a diagram. There
is even a comment about how the Throttle Position sensor
communicates to the transmission. Of course this is V-12
related. My only comment is that My kickdown switch
definitely worked at 65% throttle until I adjusted it. I
think I better take the carpet off to confirm If I can get
any more Distance to floor it and achieve 100% WOT without
adjusting cable tensions.

The Links:

www.jagweb.com/aj6eng/throttle_linkage.html

The forum discussion:
http://forums.jag-lovers.org/av.php?691689r28

I tend to search the x300 archive first as I have found that
with the x305 distributorless system there isn’t always a
direct reference to it on the v-12 or xj-s forum, its
ignition system seems much different. So alot of things
don’t apply. I wonder if I should post in the v-12 as well?

The diagram makes it seem simple enough aside from the idle
butterfly adjustment at .002. I’ll leave that as is since I
Idle at 750.

Is it me or as soon as you fix one thing, you find another
thing to do:) haha

Onwards to the throttle linkage,

Thanks again,

~Jason–
The original message included these comments:

It has been in the back of my mind as a future modification for some time
now :slight_smile:


Jason Shaguar Midnight Blue X305 95 XJ12 SWB LHD Florida,Us
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In reply to a message from Jason X305 sent Tue 9 Jun 2009:

Follow up:

Ok the link I posted regarding linkage worked like a charm.
I have both throttle linkages adjusted so that the
butterflys open exactly at the same time at 3mm throttle and
at the WOT one side hits the WOT stop while the other is at
99% at the stop. I had to adjust the the throttle ‘‘pushrods’’
to get the WOT just right. Btw one side of the pushrods has
a reverse thread locknut. Kept playing with the different
lengths and tensions and am happy with this compromise. I
sometimes waste alot of my own time tweaking to get as
close to perfect as I can. It seems only 1 out of 5 times it
pays off for me :slight_smile:

‘‘Puss’’ is growling great, Another improvement. So for all
v-12’s I highly recommend to get the linkages synchronized.

Back to on topic: My wires got pulled out of the ‘‘kickdown’’
switch and a bit of insulation was torn and I wound up
having to crimp on another connector plus tape it thanks to
my over zealous twisting it in too much. haha The switch is
in all the way but I still only get 95% ‘‘floored’’.

I am hoping that I can adjust the throttle cable between the
pedal and the traction control to take out the slack without
having to re-do my linkage adjustment.
I saw a recent thread on this and I hope it is intuitive and
easy enough to do.

I did test her out and it seemed like I got a 0-80 in like
8.5 to 9 seconds. (counting in my head)

Anyways,I’m gonna call ‘‘Puss’’ (pooss) a sports car now :slight_smile:

OOMPH! There it is!

~Jason–
Jason Shaguar Midnight Blue X305 95 XJ12 SWB LHD Florida,Us
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