[xj-s] Trip Computer

In reply to a message from rppetrey@bellsouth.net sent Wed 16 Jan 2013:

There are… You’ll need to keep the two pairs of buttons
out to get the screws in.

My trip computer does stay in on friction, so I don’t
think I bothered.–
1996 XJS 2+2 Convertible with 4.0L AJ16
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I took the old girl for a shakedown run on the weekend (the XJ-S
not the wife) and everything worked fine, started right up, threw
out a little coolant when idling which I’ll check out.
I had it on a battery tender all winter but I noticed that the
trip computer was froze up with 8-8-8-8- across the screen. Is
this because of the battery tender? Is there a way or procedure to
reboot this computer. I guess I could just pull the battery lead
and see what happens.
Hopefully it’s not pooched.–
Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada
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In reply to a message from Jagrr88 sent Tue 22 Mar 2016:

I had MY old girl hooked up to a battery tender all winter long,
too, with no adverse effects. Battery completely disconnected a
few times while I worked on the electrical system. How about
pressing the ‘‘Reset’’ button?
Dave.–
The original message included these comments:

I took the old girl for a shakedown run on the weekend (the XJ-S
I had it on a battery tender all winter but I noticed that the


Dave the Limey. 1988 XJS-C. 1960 Chevrolet Apache.
Greenville, Pa., United States
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In reply to a message from DavetheLimey sent Tue 22 Mar 2016:

I pressed it and every other button half a dozen times to no
avail.–
The original message included these comments:

few times while I worked on the electrical system. How about
pressing the ‘‘Reset’’ button?


Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada
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In reply to a message from Jagrr88 sent Tue 22 Mar 2016:

You could remove the trip computer and disconnect the wire
harnesses. Reconnect and see if any changes.–
Vans
Tucson, Arizona, United States
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Gary,

I own and drive four Jaguars with the same basic trip computer, including
my wife’s 1990 XJ-S convertible. I encountered the frozen “8-8-8-8”
display a few times in the past 16 years or so on start up. Most of the
times a power off reset fixed it. You can remove the power by either
disconnecting the negative battery terminal cable, or removing the trip
computer from the dash and disconnecting the connector. Either way the
power will be removed from the trip computer. I usually keep the power
removed for a minute or so to be sure that the trip computer fully resets,
but I have no technical basis for that time period. In one case the power
off reset did not fix the “8-8-8-8” display and I had to install one of my
spare trip computers.

If I were you I would try the power off reset. If it didn’t work the
first time, I would try it again for a longer period. If that doesn’t fix
it you probably need to get a replacement trip computer. These are on eBay
regularly, however since you are in Canada you probably would prefer one
that is calibrated in Imperial Gallons which are not the ones that came in
the USA market cars. There is a jumper wire inside the Imperial Gallon
configured units that are not in the USA version and if you cut the jumper
wire you can reconfigure it to U.S. Gallons. However, if you have a USA
Gallon version, you can not convert it to Imperial Gallons. I know this
because I have a Canadian market 1990 V12 Vanden Plas which was configured
for Imperial Gallons that I modified for U.S. Gallons by cutting the jumper
wire.

Regards,

Paul M. Novak

1990 Series III V12 Vanden Plas
1990 XJ-S Classic Collection convertible
1987 XJ6 Vanden Plas
1984 XJ6 Vanden Plas
1969 E-Type FHC
1957 MK VIII Saloon
Ramona, CA
P.M.Novak7@gmail.com-----Original Message-----
From: owner-xj-s@jag-lovers.org [mailto:owner-xj-s@jag-lovers.org] On Behalf
Of Jagrr88
Sent: Tuesday, March 22, 2016 7:28 AM
To: xj-s@jag-lovers.org
Subject: [xj-s] Trip Computer

I took the old girl for a shakedown run on the weekend (the XJ-S not the
wife) and everything worked fine, started right up, threw out a little
coolant when idling which I’ll check out.
I had it on a battery tender all winter but I noticed that the trip computer
was froze up with 8-8-8-8- across the screen. Is this because of the battery
tender? Is there a way or procedure to reboot this computer. I guess I could
just pull the battery lead and see what happens.
Hopefully it’s not pooched.

Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada

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In reply to a message from Paul M. Novak sent Tue 22 Mar 2016:

Thanks Paul, I’ll give it a whirl. I assume I have the Canadian
version as there is a slide button on the top left that goes from
imperial to metric for MPH to KPH.
thank you.–
The original message included these comments:

removed for a minute or so to be sure that the trip computer fully resets,
spare trip computers.
configured units that are not in the USA version and if you cut the jumper
wire you can reconfigure it to U.S. Gallons. However, if you have a USA
Gallon version, you can not convert it to Imperial Gallons. I know this
because I have a Canadian market 1990 V12 Vanden Plas which was configured
for Imperial Gallons that I modified for U.S. Gallons by cutting the jumper


Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada
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In reply to a message from Jagrr88 sent Tue 22 Mar 2016:

Sorry! Had to ask! A bit like- Are you SURE there is fuel in the
tank?!!
Dave.–
The original message included these comments:

I pressed it and every other button half a dozen times to no
avail.


Dave the Limey. 1988 XJS-C. 1960 Chevrolet Apache.
Greenville, Pa., United States
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In reply to a message from DavetheLimey sent Tue 22 Mar 2016:

I drove around for an hour there should be.
Actually my ritual is hose and wipe down the car every time I take
her out and throw $20.00 in the tank to avoid vapor lock issues. I
always figured the colder the gas is in the tank the less
problems. My AC isn’t working at the present. I’ve also read the
AC fuel line cooler is over rated anyway.–
The original message included these comments:

Sorry! Had to ask! A bit like- Are you SURE there is fuel in the
tank?!!


Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada
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In reply to a message from Jagrr88 sent Tue 22 Mar 2016:

Gary, you missed my point completely!
Did you try the reset button was rather like stating the
obvious!First thing I did, of course was the reply! Many times,
faced with a machine that won’t start, the first question I ask is
‘‘does the truck have fuel in it? Are you SURE?’’ You’d be
surprised how often the cure can be the most basic thing. Paul
Novak’s response sounds like a good bet, though. Good luck!
Dave.–
The original message included these comments:

Sorry! Had to ask! A bit like- Are you SURE there is fuel in the
tank?!!


Dave the Limey. 1988 XJS-C. 1960 Chevrolet Apache.
Greenville, Pa., United States
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Gary,

That is interesting. All of my trip computers, even the one for the
Canadian market 1990 V12 VdP, have slide buttons that say “mls” for miles
and “km” for kilometers. Certain Jaguar part numbers identify the trip
computers that make the Imperial Gallon vs US gallon calculations. For
instance, the trip computer in my 1990 V12 VdP has a part number of DAC4295
while the one in my wife’s 1990 XJ-S convertible is DAC4296. The DAC4296
is “USA Only” according to the Jaguar Parts Catalogue, however the DAC4295
is for “All other countries”. The DAC4295 has the “IMP LINK” that can be
cut to allow calculations based on US gallons and not Imperial Gallons.
BTW, 1 Imperial Gallon is about 1.20 US Liquid Gallons, so it is not a
trivial difference.

Regards,

Paul M. Novak

1990 Series III V12 Vanden Plas
1990 XJ-S Classic Collection convertible
1987 XJ6 Vanden Plas
1984 XJ6 Vanden Plas
1969 E-Type FHC
1957 MK VIII Saloon
Ramona, CA
P.M.Novak7@gmail.com-----Original Message-----
From: owner-xj-s@jag-lovers.org [mailto:owner-xj-s@jag-lovers.org] On Behalf
Of Jagrr88
Sent: Tuesday, March 22, 2016 9:42 AM
To: xj-s@jag-lovers.org
Subject: RE: [xj-s] Trip Computer

In reply to a message from Paul M. Novak sent Tue 22 Mar 2016:

Thanks Paul, I’ll give it a whirl. I assume I have the Canadian version as
there is a slide button on the top left that goes from imperial to metric
for MPH to KPH.
thank you.

The original message included these comments:

removed for a minute or so to be sure that the trip computer fully
resets, spare trip computers.
configured units that are not in the USA version and if you cut the
jumper wire you can reconfigure it to U.S. Gallons. However, if you have
a USA
Gallon version, you can not convert it to Imperial Gallons. I know this
because I have a Canadian market 1990 V12 Vanden Plas which was
configured for Imperial Gallons that I modified for U.S. Gallons by
cutting the jumper


Gary, Jagrr88 5.3L XJ-S 1988
Edmonton/Alberta, Canada

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Has any creative person come up with a replacement idea for the
computer in the middle of our dash? I’m talking GPS, radar
detector, etc. Anything like that?–
Murphy
St George/Utah, United States
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In reply to a message from MurphTheSurf sent Sat 25 Jun 2016:

Yes, a few of us have installed gauges in that spot. I
reworked a three gauge pod to fit. I have two Auto Meter
water temp gauge’s (sensors are in each water rail) and a
oil pressure gauge.
Larry
91 XJ-S 12cyl 5sp
95 VDP 6cyl–
The original message included these comments:

Has any creative person come up with a replacement idea for the


Larry Hartman
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In reply to a message from MurphTheSurf sent Sat 25 Jun 2016:

Hi. Id rather have the computer. I like the
look of the facelift model and I use it all the
time. Cheers. Richard–
The original message included these comments:

Has any creative person come up with a replacement idea for the
computer in the middle of our dash? I’m talking GPS, radar
detector, etc. Anything like that?


Richard Ashley. Green 95 XJS Celebration. 4.0 Ltr Coupe
Scarborough, United Kingdom
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In reply to a message from Jackdog1 sent Mon 27 Jun 2016:

My 96 came with the clock, the trip computer was
discontinued. I bought a 94 trip computer and the wood dash
panel and installed it. Trip computer plugs into the same
harnes plug as the clock, plug was wired for both. Replaced
the light bulbs in the trip computer with LEDs. They won’t
dim with the instrument light dimmer, but not too bright
for night driving.–
Ron - Purr more…Hiss less 95 XJS Coupe 4.0 , 99 XJ8L 4.0
Lawrenceville Georgia, United States
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In reply to a message from rppetrey@bellsouth.net sent Tue 28 Jun 2016:

Yeah, I’ve an idea. But,
I’ll not do it. Tinkering
got me in a mess. Resolved
at last!! Much down under work
and more than a few $'s!!

Well maybe the outboard light swap?
7’s for 5+'s ! Most of the
stuff needed is here or on the way?

To the point: I would add a compass,
inductance ammeter and a vacuum guage.
And, perhaps engine oil and
transmission oil temp gauges. Same guage
and a toggle switch for the latter two??

Way back when, school chum and I built
an A roadster as a hunting car.
Other stuff as well. A coupe, sans top
and fenders and fat tires.

Wood dash. Hoe to view the in tank
gas guage. Extra toggles. And two
ammeters. One to read + and the
other to read -!

Carl–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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Wow this a long thread spanning many years. I guess I’ll add to it.
I obtained a 1984 XJS. The trip computer did not work at all, not even the clock so I found a one locally from someone parting out a 90 XGS. The clock and average speed worked on that one but I got no MPG, just zeros’s. I bought a sender unit ($25) on ebay and swapped it out. Now I see readings on the mileage but totally inaccurate. When I step on the gas the instant MPG goes up to 30-40 or so and when I coast it drops to 1 or 2. Seems to be opposite what it should be. Any ideas?

Don,
There is a 2 position switch on trip computer in the upper left corner. Is the switch in the mls or km.position?

Paul

Hello,
One possibility that is really easy… We put a couple black Velcro strips on the Trip Computer panel and this holds our iPhone 6 plus in a horizontal position. The iPhone connects to the aftermarket stereo, and can access a large library of music, act as a speakerphone, and provide a very intelligent GPS with nice map display. The iPhone blends nicely with the dashboard, but admittedly at the cost of having a couple Velcro strips there when not installed!

Our beloved Cat is named Maxine Elizabeth Panthera. Sadly I cannot (yet) reprogram the iPhone to respond to “Maxie” instead of “Siri”, but she is nevertheless an eXperimental Joint Sentient…

:slight_smile:

Hello Sean,

First of all I’m new to all this - have been enjoying our 1991 XJS for only about a year now. Much to learn. Thanks very much for the rundown on the Trip Computer - this is very helpful.

I am very interested in exploring what is possible with regard to enhancing the Trip Computer. My career was in software development and test, and so I appreciate and am fascinated by your proposed home-brew computer, with many added features!

Just a thought - I am currently using a very simple approach - Velcro-ing an iPhone to the dash over the existing Trip Computer. This transmits via Bluetooth to the aftermarket stereo, and provides a large music library, speakerphone, and cool GPS display.

But you got me thinking. I also have a vintage Garmin Nuvi GPS in the car, and wonder if I could get a larger one that would fit the available dashboard area where the Trip Computer now resides. I recently stumbled upon a number of articles about hacking the Garmin Nuvi…

I LOVE the Garmin Nuvi user interface - it is so simple, intuitive and elegant.

Might it be possible to utilize the Nuvi touch-screen and existing GPS features, and hack it to interface to a Raspberry Pi that would act as a pre-processor for XJS sensors? The Garmin is inexpensive, the Pi is VERY inexpensive, and also very Open Source and has a rich history of amazing applications. The Pi takes so little power that it might be kept alive by a battery all the time (or perhaps draw sufficiently little power to simply run from the car battery, with a small backup battery when needed?)

This is certainly a non-trivial project, but I would love to have that great Nuvi user experience and a colorful display in a nicely sun-sheltered dash location. All kinds of alphanumeric and graphic capability once a hack is in place to turn the Nuvi into a touch-screen interface to the Raspberry Pi. I happen to be into amateur radio (too many hobbies!) and would love to set up a mobile Allstar digital node. Everything would be controlled and monitored from the Hacked Nuvi screen.

And the project would never really end - always opportunities for cool features…

Anyway, thanks again - love your site…

cheers,
-john