[xj-s] reprograming factory settings

XJ-S
1

After reviewing the 300 list, Thought I’d ask if there is a program out
there for reprogramming factory settings for shift points and fuel
efficiency/airmixture settings. IF this exists can it be loaded on a laptop
and what hardware/software is needed.

// please trim quoted text to context only

2

After reviewing the 300 list, Thought I’d ask if there is a program out
there for reprogramming factory settings for shift points and fuel
efficiency/airmixture settings. IF this exists can it be loaded on a laptop
and what hardware/software is needed.

I take it you have an X300 with a V12? If so, yes, you can change it.
The transmission is a good old GM 4L80-E (same as the TH400/3L80 but
with an overdrive gear and electronic control). You can buy a program
to change all the shift points, firmness, etc. from a bunch of
sources, including Jet (www.jetchip.com ; NAYYY). Hook up your laptop
and you can change everything.

If you have an older tranny (TH400) you need to put in a shift kit
and/or have a tranny shop readjust the shift points and firmness. Of
coures my tranny was shifting very firm for a few weeks… now it’s
dead. Oops. Then again it also had 130,000 miles and 20 years on it.
Time for the 5-speed!–
-Ted
'82 XJ-S – 5.3L V12 '98 Volvo S70 GLT – 2.4L I5 Turbo
'93 GMC Vandura 2500 – 4.3L V6
New York City, NY AIM: FordCrusherGT Yahoo: Jag_Pushrod

// please trim quoted text to context only

3

Dan asked:

Thought I'd ask if there is a program out there for reprogramming factory settings for shift points and fuel efficiency/airmixture settings. IF this exists can it be loaded on a laptop and what hardware/software is needed.

Yes & No. Roger Bywater of AJ6 engineering has a proprietary setup to do
some fancy stuff with the fueling map on 16CU ECUs :
http://www.jagweb.com/aj6eng/index5.html

Perhaps competitive to that is Prestige Spare’s ECU
http://www.prestige-spares.com.au/16cu.html

If you want to have fun doing the reprogramming yourself you’ll need an
aftermarket ECU such as a Tec III http://www.electromotive-inc.com/

There are other programmable ECU’s out there besides the Tec III & at least
a few of the members of this list have used them on their highly modified
V12 engines.

You might want to try the V12 list for further answers.

Paul Kobres
1985 XJS

// please trim quoted text to context only