740 Turbo Sedan stalling out

Hi! Yes, I STILL have my 1989 740 Turbo sedan. The main hurdle has
been the overdrive relay and solenoid. That darn up-arrow still kicks
on every now and then, but I have a much more pressing issue this
time. Darn thing cuts off and I have to throw it in Park and restart
it. At first, it would only do it when I turned the wheel too hard in
either direction. Now it's happening more often and at the most
inopportune times.
Any thoughts? Hubby suggested fuel injector cleaner, but then again
he's been telling me for years to get rid of the car.

 

Fuel injectors can't possibly be dirty enough to make it stall. Does the
tach needle drop like a rock when this happens? If so, check the crank
angle sensor. If the tach drops with the RPM, the throttle body may be
gunked up or the idle control motor could be stuck.

 

Take it to a Volvo tech its a simple problem fixed in minutes

 

That depends, cutting out can be a number of different issues. Not sure
what year this is, but if it's pre-'89 the engine harness might be
deteriorating. Could also be fuel pump relay, distributor hall sensor,
or in later cars the crank angle sensor instead.

 

John's comment isn't very helpful, and certainly is not in keeping
with the spirit of this group.

I've been having the exact same set of problems on my '92 940. I
found intermittant voltage to terminal 30 of the overdrive relay. I
just hot wired it so the OD solenoid has voltage anytime the key's
on. I can't switch the OD off and I don't like running the OD
solenoid current through the ignition switch but it's been working for
2 years now.

My engine shuting down problem is exactly the same as described.
Since the fuel pump relay is on the same relay panel as the OD relay,
I wonder if it's related. I haven't fixed it yet, as it never stays
broken long enough to check it out. Once when it died I think I
couldn't hear the fuel pump cycle when I turned the key on but it was
noisey where I was and I'm not positive. One shouldn't hot wire the
fuel pump relay as I did the OD relay because of the safety issue.
The fuel pump is supposed to shut off when the engine quits turning.
I'm thinking of installing a switched circuit to hotwire the puel
pump. Then if it starts as soon as I switch the pump on I've at least
isolated the problem to the fuel pump. BTW, I took the cover off the
fuel pump relay and resoldered all the connections. It didn't shut
off for a couple of months but eventually acted up again. It just does
it every month or two, but often enough that my wife doesn't like to
drive it. Her car is a '92 850, great car, by the way.

I really like Volvos but even I have to admit their electrical systems
suck. Even the light bulbs give more problems than other cars.

If anyone in the DFW area wants one, I need to sell my "87 940. It's
a little rough, has over 250K, but runs great and never uses any oil,
$1,000.

Steve Elms
ASE Master Technician, L-1

 

That's interesting. You can pull the whole fuse panel out, at least on
the older 700s before they moved it from the center console. Remove the
ash tray, remove the pocket above it (screw hidden behind the lighter
fascia) and then push on the clips and pull the whole fuse box forward
and lift up and the whole mess will come out on a bundle of wires long
enough to pull it out of its cave. Look underneath and you can see how
everything connects, you might just have a wire coming off a terminal block.

I think to say the electrical systems suck is a bit harsh. They had
problems with deteriorating insulation under the hood prior to '88 or
'89, but that isn't really Volvos fault, and those Bosch relays leave
something to be desired, but for the most part I find them to be pretty
dependable once you fix those two issues.

 

Thanks for all your posts. It is now a month later and I haven't had
the stalling-out issue happen any more. Tonight, however, on the way
home from work, I think the turbo went out. The needle got into the
"zone" where the turbo usually kicks in, but all that happens is a lot
of air-flow sound and rumbling and there is no turbo power.
What should I do?

 

Find out which hose ruptured or came off and replace or re-attach it.
Your turbocharger is fine.

If the problem is not obvious when you look under the hood, and the car
is an automatic, open the hood, firmly engage the parking brake, push
firmly on the brake pedal with your left foot, place the transmission in
Drive, then have someone stand to the side and watch as you gently push
the accelerator until some boost builds up. There will be a tremendous
amount of air blasting out from somewhere and that breach is what needs
to be fixed.

You shouldn't drive it much like it is, the turbine can overspeed and be
damaged with no load on it, not to mention you are letting unfiltered
air into the engine.

 

Thanks much, I'll take a look at it tonight when I get home. I did not
drive it today and I won't until the issue is fixed.