[xj-s] ABS

XJ-S
21

In my

opinion, ABS is overrated, especially here in the great white north with
icy roads.

I have found ABS to be an absolute delight. When I first got it, I wasn’t
even sure I wanted it at all. Now that I have it and have learned to use it,
I loveit! I can brake all day long in my normal (spirited) driving and never
get anywhere near the ABS point. The nice part of it is that whenever I have
to nail the brakes in an emergency, it’s already second nature to be able to
do that and concentrate on my evasive techniques without having to think
about the brakes. I wouldn’t be without it now. The situations where ABS are
not beneficial are so few and far between that I highly recommend it for
general driving. YMMV…
Cheers,
Jeb Boyd
V-12 Engine List Admin
British Car Junkie
Dillsburg, Pa
@Lisa_Jeb_BoydFrom: “Don Lawton”

22

Chris,
You paying attention? Here’s some real world diagnostics for ya!

Paul,
Nice job!
Cheers,
Jeb

There are a couple of quick checks you can do to test out the front wheel
sensors and the ECU.
If you disconnect the front wheel sensors (connections located in the
engine
bay on both inner wings just below and rearwards of the front suspension
mounts) and measure the resistance of the sensors with an ohmmeter you
should see between 800 and 1200 ohms (or there abouts, a little bit either
way won’t hurt). While you have the sensors disconnected, place a 1000 ohm
resistor across the connections on the wires that lead back to the ECU.
You
will need an assistant here 'cos the connections here are the pins of the
connector. Then turn on the ignition and wait for the usual time before
the
light normally goes out, I think the book says something like a maximum of
20 seconds. If the light goes out then the wiring and ECU is OK.
Repeat this procedure for both front wheels. This will tell you if either
of
the front sensors are shot or if the ECU is not behaving.
The same procedures can be applied to the rear wheel sensor but I don’t
know
where the connector is.

DO NOT clean electrical connections with WD40. WD40 is petroleum based and
will leave an oily residue. Use an alcohol based cleaner of some
description, I find vodka does very nicely and it has another more
pleasant
use too, once you have cleaned your contacts, you can celebrate with it.

Hope this shed a bit of light on it for you.

Paul

----- Original Message -----
From: christky@bellatlantic.net
To: xj-s@jag-lovers.org
Sent: 24 August 2000 01:10
Subject: [xj-s] ABS

90 xjs v12 conv.

Unfortunately, my ABS is shot.

The yellow light comes on right after start-up and stays on while
driving.
I know that most people in the list know nothing about the ABS, as well
as
do not have ABS. So, chances are dim that i will find the problem.
My normal brakes are good though and the brake petal has pressure, so it
is
only the ABS that malfunctions. I recently did a brake fluid change.

Anyway, at least I want to identify the faulty component.

Here is a list of all the individual components - that I know of - that
make up the ABS system on my car:

  1. ABS Pump.

  2. ABS pump fuse. This is situated in the passenger footwell. There
    areFrom: “Paul Burke”
    2
    30A fuses related to the ABS.

  3. ABS Accumulator

  4. ABS Computer (ECU)

  5. ABS Valve

  6. ABS sensors (near wheels),

  7. ABS electrical connections.

Can someone tell me at least where these items are situated on the car?

Also, I want to clean all ABS electrical connections. Where are they,
please? How do I clean electrical connections? WD40?

Thanks,
Chris.

23

What year was ABS introduced ? I have a line on an 1988 XJ-S for sale with engine problems [
dies after 15 min of running] ?

Thanks.

bob

Don Lawton wrote:> Chris:

The ABS on my '88 XJS has not worked for several years (failed computer unit). In my
opinion, ABS is overrated, especially here in the great white north with icy roads. I never
bothered to get it fixed. If yours works on one side only though, then that is not good.

Don
Calgary, '88, 160K km

24

I have already sensed the lack of ABS today: While braking hard when
someone cut me off, the right wheel locked and the left wheel kept braking.

Bzzzzt, wrong answer. Have you never owned a car without ABS? If one wheel
locks substantially earlier than another, then something else is
wrong. Some things that might cause it:

*you’ve got one wheel on the shoulder so they have unequal traction
*pads are worn unevenly, a symptom of bigger problems by the way
*brake system has lots of crap in it, so pressure is not distributed
evenly
*caliper is jammed
*tire pressures aren’t even

I’m sure there’s more, but that’s what immediately comes to mind.

Look, I dunno how to make this clear enough, so I’ll try this. My 1970
Dodge Charger has manual brakes, front disc, rear drum, and it stops
straight every time. Every time! Every disc-brake equipped car I’ve owned
has always stopped straight, and when it didn’t, there invariably was a
problem to be fixed. [4-wheel drum brakes are another matter; get them wet
and things can get pretty exciting]

I’m in the same boat as you. I have a Bonneville with a bad PMV assembly
(the modulator) so the ABS doesn’t work on that car either – I considered
the $500 price on the Pontiac assembly prohibitively expensive, but now I
see that it is a relative bargain. Anyway my point is that I’ve been
driving it for 8 months with no ABS and have not had any trouble braking
in a straight line.

It is prohibitively expensive to do this ABS job.

So fix whatever else is wrong with your brakes, because something else
isn’t right, and drive without it.

It will take a little used to to learn to brake effectively without ABS.
Seems that I have to simulate the ABS pumping myself every time one, or
both wheels lock during braking.

If BOTH wheels lock during braking, then you’re just plain stopping too
hard! How many panic stops do you make in a day?! Sounds like this ABS
thing could be a good opportunity to re-evaluate your following distances.

I can’t say this enough: your brakes will work normally without ABS. The
only time ABS even affects your life when it’s working is during panic
stops.

Cheers,
Bry

25

Jeb,

I agree with you if your daily driver is the type that gets used and
replaced every 5-7 years. I tend to buy a car and keep it forever, though,
and the expense of those ABS parts don’t strike me as a good value for
what little return they provide.

Cheers,
BryOn Sat, 26 Aug 2000, Lisa & Jeb Boyd wrote:

I have found ABS to be an absolute delight. When I first got it, I wasn’t
even sure I wanted it at all. Now that I have it and have learned to use it,
I loveit! I can brake all day long in my normal (spirited) driving and never
get anywhere near the ABS point. The nice part of it is that whenever I have
to nail the brakes in an emergency, it’s already second nature to be able to
do that and concentrate on my evasive techniques without having to think
about the brakes. I wouldn’t be without it now. The situations where ABS are
not beneficial are so few and far between that I highly recommend it for
general driving. YMMV…
Cheers,
Jeb Boyd
V-12 Engine List Admin
British Car Junkie
Dillsburg, Pa
l.boyd6@gte.net

26

I thought on icey roads and snow was the very place that ABS was the best
? ?

The difference between a car with ABS and a car without ABS on an icy raod
is that you will go straight through a stop sign instead of sideways.

ABS is usually better in snow, but sand and gravel do confuse it. All of the
situations that ABS may be suspect are extreme conditions where any braking
will be treacherous and requiring finesse.

Basically, you have to acclimate yourself to their function. Jaguars have
particularly good brakes to begin with, so any use of the ABS is limited.
This state of dormancy creates problems. you can drive most Jags in semi
severe braking conditions and never get anywhere near the anti-lock
engagement. This is why intensive attention to service and maintenance is
critical in these systems.
YMMV,
Jeb Boyd
V-12 Engine List Admin
British Car Junkie
Dillsburg, Pa
@Lisa_Jeb_BoydFrom: “M T Barksdale”

27

I agree with you if your daily driver is the type that gets used and
replaced every 5-7 years.

So you’re saying that ABS is only good for five to seven years? I’ll agree
with that…if you never service or maintain it. It seems to be
unnaturally fussy, but if you keep after it, the ABS should be great for a
long time…but how many people are going to be willing to flush a gallon
to a gallon and a half through the system once a year? It’s a bad situation.

I tend to buy a car and keep it forever, though,

and the expense of those ABS parts don’t strike me as a good value for
what little return they provide.

If they save your butt once they have paid for themselves. The Subaru I’m
driving, I have now had for two and a half years. If that system craps out
now I don’t feel that it would owe me anything. But I’m going to keep after
it 'cause it works great and I have learned to let it help me in a bad
situation.
Cheers,
JebFrom: “Bry in Virginia”

28

Hi all:

Further to Jeb’s comments:

The difference between a car with ABS and a car without ABS on an icy raod
is that you will go straight through a stop sign instead of sideways.
ABS is usually better in snow, but sand and gravel do confuse it. All of the
situations that ABS may be suspect are extreme conditions where any braking
will be treacherous and requiring finesse.

In icy conditions, the main problem is that people think that ABS will make them stop
more quickly than if they don’t have ABS (same applies to myths about 4x4s). The only
way to sop quickly on ice is if you hit something, usually bigger than you.

Another issue, at least with early ABS units, is that if you lock all wheels instantly
(easy to do on ice), the ABS computer figures you had already come to a stop.
Meanwhile you are sliding out of control towards a concrete post or other
unforgiving object. Maybe the new ones are smarter ?

Don
Calgary. '88, 160k km

29

From: “Don Lawton”
In icy conditions, the main problem is that people think that ABS will
make them stop
more quickly than if they don’t have ABS (same applies to myths about
4x4s).

It’s four wheel DRIVE, not four wheel STOP! I have never understood why the
average driver of 4X4s doesn’t seem to get that.

The only

way to sop quickly on ice is if you hit something, usually bigger than
you.

Like a bridge…

Another issue, at least with early ABS units, is that if you lock all
wheels instantly
(easy to do on ice), the ABS computer figures you had already come to a
stop.

Now that’s a cool quirk. I never heard that. I have seen people pump the
pedal like crazy and confuse the ABS badly. Is that common to all early
systems? Define early, too, as I was sort of under the impression that the
Teves system is an early system. When were the first systems used and on
what?

Meanwhile you are sliding out of control towards a concrete post or other
unforgiving object. Maybe the new ones are smarter ?

I know that the most difficult thing that I had to learn with ABS and snow
and ice was to back off the brakes if the ABS was just chattering away and
not really slowing. It’s not a natural action. It also makes you review your
respect for winter. Something I’m sure Don can relate to.

I do like the ABS in more normal conditions. In day to day driving when the
average moron pulls the average stupid maneuver, it’s nice to have it in the
back of your mind that you can just nail the brake pedal and concentrate on
getting out of his way.

Isn’t there anybody out there other than me that likes ABS?
Cheers,
Jeb

30

systems? Define early, too, as I was sort of under the impression that the
Teves system is an early system. When were the first systems used and on
what?

They started installing ABS on Corvettes in 1986. It was some sort of
Bosch system.

Isn’t there anybody out there other than me that likes ABS?

I’ve had two ABS-equipped cars, spanning five years of driving. While it
was kind of nice to have, I can’t say that I’ve had any situations where
the ABS unequivocally prevented an accident. Certainly when the $600 PMV
assembly went kaput on one of them, I haven’t exactly rushed out to
replace it. If I can find a good used one at a junkyard, for a lot less
money, maybe.

So I guess you could say, yes, I like ABS until I have to pay for it.

Cheers,
Bry

31

In a message dated 8/27/00 9:11:32 PM, bryfs@spacebears.com writes:

<< > systems? Define early, too, as I was sort of under the impression that
the

Teves system is an early system. When were the first systems used and on
what?

They started installing ABS on Corvettes in 1986. It was some sort of
Bosch system.

Isn’t there anybody out there other than me that likes ABS? >>

Hi,
I had a 1986 Mercedes 560SL that had ABS, And a driver side air bag. I like
ABS. A lot!
Tony
Observation:
“I learn the most from my mistakes when I remember that
my current situation is the result of my previous choices.”

32

Date: Sun, 27 Aug 2000 10:32:33 -0400
To: “Lisa & Jeb Boyd” l.boyd6@gte.net
From: “Dr. Mac Barksdale” <@M_T_Barksdale>
Subject: Re: [xj-s] ABS

Just a short plug for the ABS. As a Florida driver I do not need it
often. We do have a condition where a lot of oil and sand accumulates on
a roadway with a week or so of no rain to wash the road. THEN when a
shower comes… not a heavy rain… Woweeeee is that slick for a few
minutes… slick as a peeled onion.

One can expect accidents all over town for the first half hour. And then
the second condition is our regular Christmas trip north.

With that setting of the stage, may I say that I DO like the Jag ABS
system… And you are right that many folk abuse it rather than use
it. It DOES take some getting used to. I found that in snow and other
slippery going it will allow steerage to be maintained. Not possible with
locked wheels.

I once made a sudden decision [not good on snow] to exit an interstate and
even more suddenly found that the exit had not been plowed… so there I
was at 70mph on 4 inches of snow quickly running out of ideas and
options. No problem the anti skid worked well and I maintained
control. Miraculous !

I am accustomed to anti skid on aircraft. The system on the Hawker Jet
is an early French system called “Maxaret” [The early Hawker does not
have reverse thrust] It is a purely mechanical system operating on
centrifugal force [centripedal] to modulate the antiskid function. It
hardly ever fails being non electronic and having no complex sensors etc
etc. There is plenty of power available with 3000 pounds of hydraulic
pressure being the nominal system pressure. It can literally throw
passengers out of their seats if not belted in well. Apply with caution
! Also it takes away the problem of the pilot modulating the individual
brakes, [left side independent of right side] so as to stop evenly with
out "fishtailing’.

Sorry to be so windy… I could have just said I like the Jag system of
anti skid.

Regards,

Mac

Mac Barksdale, DVM
4270 Aloma Ave Suite 124-33A
Winter Park, Florida 32792
@M_T_Barksdale
407 342 0938

33

Early? Well, I remember driving a JensenFF with ABS back around '71. I
believe it was a Dunlop system. Four-wheel drive, ABS and a big honking
Chrysler V-8. It was a blast to drive and stuck like glue.

As for modern ABS: My wife’s '88 Honda went almost 400,000 miles and the
brakes worked as good the day we sold it as they did when it was new.
Replace the pads, turn the rotors not more than once, make sure things are
clean and properly lubricated so the calipers don’t stick and things last a
long time.
Her new Honda sprung a leak in the ABS accumulator right after the warranty
expired. The damn price has a comma in it!! It’s a slow leak, so I plan on
topping it up once in a while and giving the problem to the next guy.

MikeC----- Original Message -----
From: Bry in Virginia bryfs@spacebears.com
Cc: Jag- Lovers xj-s@jag-lovers.org
Sent: Sunday, 27 August, 2000 7:58 PM
Subject: Re: [xj-s] ABS

systems? Define early, too, as I was sort of under the impression that
the
Teves system is an early system. When were the first systems used and on
what?

They started installing ABS on Corvettes in 1986. It was some sort of
Bosch system.

Isn’t there anybody out there other than me that likes ABS?

I’ve had two ABS-equipped cars, spanning five years of driving. While it
was kind of nice to have, I can’t say that I’ve had any situations where
the ABS unequivocally prevented an accident. Certainly when the $600 PMV
assembly went kaput on one of them, I haven’t exactly rushed out to
replace it. If I can find a good used one at a junkyard, for a lot less
money, maybe.

So I guess you could say, yes, I like ABS until I have to pay for it.

Cheers,
Bry

34

Here! Here! w/Jeb’s comments. Even racing, I never get into the ABS (properly
modulated stops shouldn’t), but when the child ran in front of the car a few
months ago, well…

It’s a bit of a pain to maintain, but the life it will save may be yours.

Emile

'93 XJR-S
'95 XJS 4.0
'96 XJR

Lisa & Jeb Boyd wrote:> From: “Don Lawton”

In my

opinion, ABS is overrated, especially here in the great white north with
icy roads.

I have found ABS to be an absolute delight. When I first got it, I wasn’t
even sure I wanted it at all. Now that I have it and have learned to use it,
I loveit! I can brake all day long in my normal (spirited) driving and never
get anywhere near the ABS point. The nice part of it is that whenever I have
to nail the brakes in an emergency, it’s already second nature to be able to
do that and concentrate on my evasive techniques without having to think
about the brakes. I wouldn’t be without it now. The situations where ABS are
not beneficial are so few and far between that I highly recommend it for
general driving. YMMV…
Cheers,
Jeb Boyd
V-12 Engine List Admin
British Car Junkie
Dillsburg, Pa
l.boyd6@gte.net

35

The Jensen had what was called the Dunlop Maxeret braking system, derived
from aircraft components.
I had one years ago, a great car.

Andrew Holley----- Original Message -----
From: “Mike Cogswell” mcogswel@mnsinc.com
To: “Bry in Virginia” bryfs@spacebears.com
Cc: “xj-s” xj-s@jag-lovers.org
Sent: Tuesday, August 29, 2000 9:37 AM
Subject: Re: [xj-s] ABS

Early? Well, I remember driving a JensenFF with ABS back around '71. I
believe it was a Dunlop system. Four-wheel drive, ABS and a big honking
Chrysler V-8. It was a blast to drive and stuck like glue.

As for modern ABS: My wife’s '88 Honda went almost 400,000 miles and the
brakes worked as good the day we sold it as they did when it was new.
Replace the pads, turn the rotors not more than once, make sure things are
clean and properly lubricated so the calipers don’t stick and things last
a
long time.
Her new Honda sprung a leak in the ABS accumulator right after the
warranty
expired. The damn price has a comma in it!! It’s a slow leak, so I plan
on
topping it up once in a while and giving the problem to the next guy.

MikeC

----- Original Message -----
From: Bry in Virginia bryfs@spacebears.com
Cc: Jag- Lovers xj-s@jag-lovers.org
Sent: Sunday, 27 August, 2000 7:58 PM
Subject: Re: [xj-s] ABS

systems? Define early, too, as I was sort of under the impression that
the
Teves system is an early system. When were the first systems used and
on
what?

They started installing ABS on Corvettes in 1986. It was some sort of
Bosch system.

Isn’t there anybody out there other than me that likes ABS?

I’ve had two ABS-equipped cars, spanning five years of driving. While it
was kind of nice to have, I can’t say that I’ve had any situations where
the ABS unequivocally prevented an accident. Certainly when the $600 PMV
assembly went kaput on one of them, I haven’t exactly rushed out to
replace it. If I can find a good used one at a junkyard, for a lot less
money, maybe.

So I guess you could say, yes, I like ABS until I have to pay for it.

Cheers,
Bry

36

The situations where ABS are

not beneficial are so few and far between that I highly recommend it for
general driving. YMMV…
Cheers,

The problem that people in the North have with ABS is that we have to use it.
Knowing that you have it, while driving on a dry road, is very reassuring. But
on ice or snow, ABS does not allow you to steer while braking and does increases
stopping times (increases impact velocity). Unfortunately for me, braking on ice
or snow is not a situation “few and far between”. Between October and March
its called a red light.

Richard Drozdowski
1992 XJS - Edmonton

37

Richard Drozdowski wrote:

ABS does not allow you to steer while braking and does increases
stopping times (increases impact velocity).

I don’t agree from my experience, albeit in my Vanden Plas (the XJ-S is worthless in
snow/ice). Jamming on the brakes allowed perfect steering in the VDP. Perhaps it is
not as effective in the XJS?

Wayne Estrada
1989 XJ-S Convertible (Dorchester Grey)
1989 Vanden Plas Sedan (Alpine Green)
Richmond VA, USA
http://www.u3training.com/jaguar

38

The problem that people in the North have with ABS is that we have to use
it.
Knowing that you have it, while driving on a dry road, is very reassuring.
But
on ice or snow, ABS does not allow you to steer while braking

Not true at all. Steering and braking simultaneously with the assistance
of ABS works much better than it does without.

John

39

Just to cheer you all up I have a little story…
About two or so years ago my ABS started misbehaving itself.
When the ABS warning light was illuminated, the brakes would work fine (no
ABS of course, but then again - who needs it eh?).
When the light went out the brakes would work fine until the speed fell very
low - almost stopped in fact, then the left front wheel would judder as the
ABS kicked in. This was not a major problem as I was aware what would happen
if the light was on or off and the brakes worked generally very well.

Anyway, back to the story.

After a little the ABS light would stay on all the time so I knew I had no
ABS but everything else was fine.
Then I was travelling to look at a new house with the misses and her mother
in the car, it was chucking it down with rain and I was driving around town
on a three lane bypass, fairly heavy stop-go traffic when a huge lorry
pulled into my lane about six feet in front of me. I was only doing about 30
to 35MPH, the lorry was going considerably slower, there were cars either
side so I stamped on the anchors and braced myself for the impact. The ABS
light went out, the ABS worked properly and I missed the truck. When I
regained the hearing in my left ear from the mother-in-law shouting at the
lorry driver (as if he could hear) I noticed the ABS light had come on
again.
It never worked again.
Was someone looking after me that day or what? You be the judge.

Paul

The problem that people in the North have with ABS is that we have to
use
it.
Knowing that you have it, while driving on a dry road, is very
reassuring.> But
on ice or snow, ABS does not allow you to steer while braking

Not true at all. Steering and braking simultaneously with the assistance
of ABS works much better than it does without.

John

40

But on ice or snow, ABS does …
increases stopping times (increases impact velocity).

Has the same effect here in Florida on dirt, sand, or gravel roads.
I mentioned that effect to a friend with a Chevy pickup with ABS who
lives on a dirt road, and he said, “I was wondering about that! The
thing doesn’t seem to want to stop at all in the street in front of
the house!”

– Kirbert | Palm’s Postulate:
| If anything is to be accomplished,
| some rules must be broken.
| – Kirby Palm, 1979From: “Richard Drozdowski” sssedm@compusmart.ab.ca