1994 Volvo 850 stalls, slow restart...with a wrinkle

Hi everyone,

I have a ’94 Volvo 850 and a while ago it started stalling. It has a
bit of a rough idle that has improved a little with non-ethanol fuel
and fuel injector cleaner. I honestly don’t know if that is related
to the main problem.

The main problem is the stalling. Sometimes, it will just stall when
I’m stopped at a light. Sometimes, it will stall when I’m going 30
miles an hour. Sometimes, it will stall when I’m going 70 miles an
hour. Typically, when it stalls at slower speeds or at the light, it
just dies straight away. When it dies at higher speeds, the first
thing I notice is "hitch" or a "bump" sensation at which point the
engine stops responding to depression of the accelerator pedal. The
engine continues to run for a few seconds as I roll along. The
tachometer slowly falls and then the engine dies.

There was a time when I could throw it into neutral and get it started
again before coming to a complete stop from highway speed, but those
days are gone. It seems that it is taking longer and longer to get it
restarted. The car has to have the key in the off position for a
minimum of 10-15 seconds before it will even have a chance to restart.
Lately, after about 30 seconds to a minute it will restart very
briefly and then immediately die. If I’m patient and wait a bit
longer it will restart like normal, but it seems more likely to die
again if I don’t wait a generous amount of time.

This problem seems to very rarely occur during long trips, but I can’t
tell if that is relevant or just secondary to the fact that I take I
take relatively few long trips. Of course, if it were completely
random it should occur more often during these 5 hour trips since it
seems to happen so often on the shorter trips.

It’s been to the mechanic at least twice for this problem. The
mechanics say that the car is not displaying any "codes." They
replaced the fuel filter the first time without improvement. The
second time, it was in for other things too and they were unable to
"recreate" the stalling despite driving it for 40 miles. They said
that without any codes or being able to recreate the stall, they
didn’t want to just "do something."

I’ve read some posts from people with similar cars and problems.
Seems like the things that come up most often are the fuel pump, fuel
relay, and oxygen sensor. However, only the fuel pump and fuel relay
seem to be mentioned when there are no codes. Is that at all
accurate? Do the symptoms the car is having seem more compatible with
the fuel relay or the fuel pump or something else entirely. I haven’t
tried to "listen" for the fuel pump when it happens before, would
that be likely to help?

Thanks a ton for any help.

Pid

 

That sounds exactly like what my 740 did. I don't know how similar the
engines are, and I actually doubt they are similar enough for this to be the
cause of your problem, but.....mine was caused by the auxiliary air valve
pipe, right on top of the inlet manifold, working itself loose. Check yer
pipes!

Si

 

Could be, my '80 260 did exactly the same. It happened once, stopped dead
and would not start at all. So dead I didn't believe that could stop it,
even after I noticed the hose had fallen off one end.

 

Long shot, but worth a go- try waggling the key in the igntion with the
engine running. If the engine dies you've foudn the problem- ignition
switches are a known weak point on the 850.

If thats ok, it sounds like a dodgy fuel pump relay to me.

Tim..

 

Exactly - I was thinking that something major had died!

Si

 

A good point - my 740's ignition switch takes very little turning to stop
the engine.

Si

 

http://www.autoforumz.com/eform.php?p=684675

I have a 850 T5 wagon with exactly the same problem and the mechanics at
Volvo have only mentioned the fuel pump (maybe). I don't know what to do...

 

In my case, was the first thing they have done (at Volvo): changing the
ignition switches.

The problem remain the same...

 

Air mass meters can cause this without leaving a code, believe it or
not. The fuel pump relay (#103 under the cover behind the fuses) and
the main relay (gray relay above the rad beside the fan relay) can also
cause you this kind of grief. Also the engine speed sensor can be the
culprit. Of course there's no way to tell without trial and error,
unless the failure happens when you're in a position to troubleshoot.

--
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.)

 

You forgot to mention the cam position sensor (which would probably
leave a code), an erratic sticking fuel pressure regulator, various
vacuum leaks that may or may not trigger a code, restricted throttle
housing, chafed or rubbing harness that could be faulty anywhere, water
in the fuel tank, a partially restricted fuel sock on the fuel pump
pickup, loose or partially backed out terminal in one of the banana
plugs under the dash, a faulty coil or coil wire, wrong spark plugs,
loose or leaking turbo hoses, sticking EGR valve or a restricted or
leaking PCV system. I agree, you kinda' have to be there when it happens
in order to get some idea of which way to go.

Bob

 

I could use those last two paragraphs as the opening for my
autobiography!

My '74 Ford 4wd pickup- when I got it, after some effort, it ran
great. Then after a bit, it would just die after running various
amounts of time (ten to 30 minutes). I would work on it at the side of
the road, and then, without reason, I would get in it and it would
fire right up and run great.

One time when it died, I took the top off the carb and the float bowl
was empty. It ended up being rust in the tank that clogged the fuel
filter. Stop the truck, gravity would settle the rust, and off she
would go again. Even after a change of fuel tanks (get a NEW one) and
flushing of the lines, I put a replaceable filter in the line before
the fuel pump it still happened. I still had to clean the filter every
two weeks or so for months before it stayed clean.

And DON'T EVEN GET ME STARTED on Air Mass Meters! ;-)
I have three tested and working spares now.. OK, so I'm paranoid!


__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"