volvo 850 stalls

We have a 1993 Volvo 850 that once every two weeks or so... just stalls.
It happens at any time..... but usually when we are driving it... with
foot on throttle. After stalling, all dash lights are on... and the car
restarts everytime. The fuel pump in the tank was recently replaced but did
not fix the problem.
Any ideas?

Much thanks in advance!!

JP

 

No "check engine" light, I assume? Does the engine quit instantaneously like
you turned off the ignition or does it fade over a half second or so like
you'd lifted your foot from the throttle?

Mike

 

No "check engine" light, I assume? Does the engine quit instantaneously

It just quits as though the key is turned off and the is no check engine
light activity at all while the engine is running.

 

The sudden shut-down points to an electrical/electronic failure rather than
the fuel pump quitting or other fuel delivery problem, which tend to fade
away as the fuel pressure drops. The lack of a "check engine" light suggests
the system thought it was doing the right thing, which leads us to things
like intermittent ignition switches rather than intermittent crank angle
sensors... but that part is still not something you can hang your hat on.

Mike

 

I don't want to steer you in the wrong direction, but my '98 S70 just
had the same problem. Sometime after driving for at least 30 minutes,
the car would stall, but immediately restart. Because I have a '98 V70
as well (I bought the S70 to match the V70 exactly for this purpose, do
I know Volvos or what?) I started swapping parts. First 3 attempts
(fuel pump relay, crank position sensor, ignition coil) left the S70
still stalling. Fourth attempt was air mass meter, and then the V70
stalled. Never before have I been happy to have my car stall on me.
Also, like you, no activity from the check engine light.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

The 850's have piss poor switch for the ignition and its quite common for
these to fail in the way you describe. I had too many keys and the weight of
them rocking with the motion of the car was enough to turn the switch off. I
believe its quite easy to replace the contacts in the switch, so something
you can do yourself. Try www.volvospeed.com Its a very good web site and
shows how its done.

ttfn.....Alistair