Strange 850 saga

For about a year the ABS light on my '97 850 has come on when it felt
like it (more times on than off especially in the Texas summer). I
checked several sources and got a lead to the right rear wheel sender
but never pursued it. The brakes worked fine.

About six months ago, my speedometer/odometer started working when it
bloody well felt like it (eventually more time not than otherwise).

Took it to the shop and, after some research they said that there's
this little gear in the speedo that goes bad. I told them that was not
what I was seeing but they ordered the gear. The dealer sent the wrong
gear and they called me to tell me this. Again I expressed my
misgivings about the "little gear" story. Again they went to research
the matter.

They called me and said they had found references to the ABS computer
causing the speedometer to fail. Now I once replaced the $12 cable to
the speedo in my 164 and had a degree of culture shock at this ABS
story but I told them to proceed.

Car returned three weeks ago with no ABS light showing. Speedometer
works ALL the time. Brakes work just as intended.

There's apparently a reason I don't do my own work any more. Up
through the mid-period 240s I could understand and figure out what to
do even converting a FI 140 to a carburetter. Long story there. A FI
fuel pump will make a carb spout like a water fountain.

Thought you might enjoy this story, improbable as it is.

Chuck Fiedler
Nothing but Volvo since 1973

 

In an earlier contribution to this discussion,

Not sure why it's improbable!

Long gone are the days of mechanical speedometers driven by a rotating cable
from the gearbox. Today's speedos are all electronic, using pulses from a
sensor mounted near a rotating toothed wheel. It makes sense to 'borrow' a
signal from the ABS sensor for this purpose, 'cos that's measuring vehicle
speed (assuming that your not skidding along with the wheels locked). <g>
--
Cheers,
Roger
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I'd sure as heck rather deal with newer electronics than older
mechanical stuff, but that's just what I understand the best.

The speedometer problems are usually worn out electrolytic capacitors
and/or cracked solder joints on the circuit board.

The ABS problem is most often cracked solder joints in the ABS module,
it's about a 20 minute fix for someone handy with a soldering iron.

I *despise* carburetors. Fiddly imprecise things, EFI is superior in
every way except complexity, but it more than makes up for that in
improved fuel economy, reduced emissions, better throttle response, and
nothing to adjust. Later cars that tried to hack carburetors to comply
with emissions standards were a nightmare. Just look under the hood of a
late 80s carbureted Honda, they make the most complex EFI systems look
downright simple.

 

: Chuck Fiedler wrote:
: > For about a year the ABS light on my '97 850 has come on when it felt
: > like it (more times on than off especially in the Texas summer). I
: > checked several sources and got a lead to the right rear wheel sender
: > but never pursued it. The brakes worked fine.
: >
: > About six months ago, my speedometer/odometer started working when it
: > bloody well felt like it (eventually more time not than otherwise).
: >
: > Took it to the shop and, after some research they said that there's
: > this little gear in the speedo that goes bad. I told them that was not
: > what I was seeing but they ordered the gear. The dealer sent the wrong
: > gear and they called me to tell me this. Again I expressed my
: > misgivings about the "little gear" story. Again they went to research
: > the matter.
: >
: > They called me and said they had found references to the ABS computer
: > causing the speedometer to fail. Now I once replaced the $12 cable to
: > the speedo in my 164 and had a degree of culture shock at this ABS
: > story but I told them to proceed.
: >
: > Car returned three weeks ago with no ABS light showing. Speedometer
: > works ALL the time. Brakes work just as intended.
: >
: > There's apparently a reason I don't do my own work any more. Up
: > through the mid-period 240s I could understand and figure out what to
: > do even converting a FI 140 to a carburetter. Long story there. A FI
: > fuel pump will make a carb spout like a water fountain.
: >
: > Thought you might enjoy this story, improbable as it is.
: >
: > Chuck Fiedler
: > Nothing but Volvo since 1973
:
:
:
: I'd sure as heck rather deal with newer electronics than older
: mechanical stuff, but that's just what I understand the best.
:
: The speedometer problems are usually worn out electrolytic capacitors
: and/or cracked solder joints on the circuit board.
:
: The ABS problem is most often cracked solder joints in the ABS module,
: it's about a 20 minute fix for someone handy with a soldering iron.
:
: I *despise* carburetors. Fiddly imprecise things, EFI is superior in
: every way except complexity, but it more than makes up for that in
: improved fuel economy, reduced emissions, better throttle response, and
: nothing to adjust. Later cars that tried to hack carburetors to comply
: with emissions standards were a nightmare. Just look under the hood of a
: late 80s carbureted Honda, they make the most complex EFI systems look
: downright simple.

I miss fiddling with an SU carb. One jet! What could be simpler?! Twin
SU's..... even better! Synchronizing them with a rubber tube stuck in my
ear.......Happy Days.

Andy I. ('58 445 "Duett" wagon; '65 122S wagon; '67 121 2-dr. Import; '74
145 wagon; '74 142 2-dr.; '86 245 wagon; '93 245 "Classic" wagon;
'97 850 AWD wagon LP Turbo (at least it has a stick shift.......... like all
our others).

 

I'm with you. Been driving 10 year old Volvos since 1980. Once I got
into the front drive with a 95 850, I had to give up most repairs. I
converted to a 2 bbl carb from the twin SUs on my 80 245. Made it
pretty zippy, but nothing like the new turbos. Just got a 99 s-70 t5 and
it's way too fast. billy

 

As an academic, I always found working on my cars highly therapeutic
since it was so very different from the day job. I actually liked the
grime under my fingernails and the skinned knuckles. I took care of my
own VWs through the '70s and '80s, including what I thought <ha ha> were
some pretty impressive repairs and -- most importantly -- I had great
fun.

I got my first (second-hand) Volvo in 1989 but never had much occasion
to work on it. Got the 850T new in '95 and have only been able to do a
few fairly simple repairs on it myself. (Thank luck it hasn't needed
anything really major.)

I would say that the days of the old 'shade tree mechanic' are well and
truly over. Sure, there was always the 'special tool' that made a job
highly difficult (or impossible!) to attempt as an amateur. But
nowadays, with the widespread electronics, etc., there are obviously
far, far fewer guys who are able to tackle things on their own. In a way
it's too bad, but hey -- when you look closely, the good old days
weren't exactly 100% rosy either. (Grease job? Ask a kid today about a
grease job and you'll get 'Huh?')

cheers,

Henry

 

I really don't think that's the case. Every time something new comes
along, a portion of the old timers don't understand it and are not
inclined to learn, but a new generation comes along and having grown up
with this stuff, don't find it intimidating. This happened when
mechanical devices were being replaced by electrical devices, then when
electrical devices using vacuum tubes came about, then when vacuum tubes
were being replaced by transistors, again when transistors were being
replaced by integrated circuits, and has happened again with each new
generation of miniaturization and integration, people complain that the
new stuff is too complex to work on. Even at 30, I'm already seeing
generations of gradeschool kids who are more up to date with computers
than I am, and when I went to the Maker Faire a few months back they had
a course on soldering surface mount components, those teeny tiny parts
that old techs have been whining are impossible to work with, and there
were 8 year olds in there building their kits alongside everyone else,
using parts that a few years ago people thought were impossible for a
hobbyist to work with.

There's plenty of people out there who are still stuck with carburetors
and think fuel injection is impossibly complex or can't be serviced
without special tools, etc. That's just not true. These days you can get
a decent multimeter for under 50 bucks that is all you need for most
diagnostics, and when broken down into the basic building blocks,
injection is not any more complex than a carburetor with all its
intricate bits and pieces, it's just different. 95% of injection
problems are caused by simple things like corroded connections and bad
sensors, most of those remaining are old fashioned mechanical stuff,
fuel pressure regulator, dirty injectors, etc. I built my own EFI system
(Megasquirt) from plans available online and have been running it in my
daily driver for a few years now, as have hundreds of others around the
world, it isn't black magic, but rather some simple and straightforward
hardware governed by clever software.

Late model cars have a lot more bells & whistles, and they do have a lot
of computers but these systems too can be broken down into reasonable
sections and problems diagnosed. The onboard diagnostics are far more
sophisticated than they were in the past and the equipment necessary to
talk to the OBD system is affordable. As with the earlier stuff, the
most common problems can still be traced to bad connections.

Nobody "has" to give up doing their own repairs, they simply choose to
because they are not interested or willing to learn how to work with the
something new and different. I'm much more comfortable tinkering with
modern electronics than finicky old carburetors, the latter feels more
like "magic" to me than a computer, and in fact I'm always amazed that
such a jumble of mechanical linkages, diaphragms, and venturis can ever
be made to work right and that will be more the case for the next
generation. A 240 is dead simple to work on, but part of that is based
on the fact that I've been working on them for close to 15 years now and
know them pretty much inside and out like the back of my hand. An 850 is
very different at first glance, but once you get familiar with it, it is
only marginally more complex than a 240. Parts look different, they are
located in different places, and there are more parts related to
additional features the 850 has, but when it comes down to it there are
more similarities than differences and becoming familiar with it is 90%
of the battle. The latest generation Volvos share much in common with
the 850, and are only incrementally more complex, they too can be
diagnosed and serviced by someone who is inclined to do so.

 

Your comments are well thought out and you make some interesting points.
However, the mindset reflected in your thinking makes it clear indeed
that a paradigm shift has occurred -- which actually proves my point.

It is a truism, of course, that the world is always changing and that
adaptation to change is 'the secret of the universe'. But the question
here is not merely the willingness or unwillingness of old codgers to
learn new skills. It is, rather, the possibility or impossibility of
performing a desired task under the circumstances prevailing, and with
the resources available, at the time.

You speak of the Maker Faire and eight-year-old solder wizards. I am
talking about hurrying to finish a job before the sun goes down and you
can no longer see what you're doing. Yes! As hard as it might be to
imagine nowadays, it used to be possible to work on cars even _without
electricity_. The proverbial repair with 'baling wire and bubble-gum'
was always a bit of an exaggeration but it did typify what is now
undeniably a bygone era. And that's all I was trying to say.

cheers,

Henry

 

Well, despite all that, I *have* actually used bailing wire to repair my
car, albeit temporary. Not too long ago when the hanger rusted off of
the muffler on my 740, I ended up tying the thing up with said wire, it
wasn't pretty but it got me by for a couple months until I had time to
change the exhaust system.

Belts, hoses, and electrical connections are all things that are not
going to vanish any time soon, and all of them can be repaired with
basic tools in many cases.

 

I particularly hate the way they stop working properly when you go round
corners hard, and carb cars take much longer to start a week or 2 of
being laid up. Really the only reason they lasted so long was because
car manufacturers didn't have the necessary skills in electronics to
understand the benefits of EFI, its amazing they managed to get carbs to
work aswell as they did. I would say carbs are much more complex than
EFI, unless you count the computer as hundreds of parts.

In fact older EFIs are also quite unnecessarily mechanical, using
thermoswitch controls for idle valves and cold start injectors.

 

Bailing wire hasn't been used in bailers for years. It is used a lot
for stove pipes, but not bailing. Bailers use twine or similar ropes.
We bailer twine a lot in Scouts since it comes in 4 mile long 2-roll
packs and can be used for lashing projects. It has 110 lb. strength. A
4 mile long set of 2 bales costs $60. It obviously has limited use in
fixing cars. There, wire is much better. There is one company that
exports bailing wire to the US from India, but I doubt it is used in any
modern bailer. Basically any #8 steel wire is called bailing wire even
though it is sold in quantities too short to use for any bailing
operation.

I usually keep a couple clothes hangers and duct tape in a car. I
seldom need it to fix the car, but it comes in handy for lots of things.

 

'Baling wire' and 'balers', surely; even in American English. 'Bales' of
hay, my friends.

cheers,

Henry

 

Sounds like the typical ABS-electronic control unit failure because of soldering
failure.
I had mine resoldered some weeks ago. During the repair, when the unit was not
in the car, the speedometer and tempomatic did not work. So a failing
ABS-control unit probably could make the speedometer fail.

I hope it remains like that.

Franz47