Volvo: 93 940 turbo station wagon stalls, foriegn car, fuel injection cleaner

Question
Stalls more with the tank less than 1/2 full.

Tach dies all the way down (sometimes from as high as 1.5 to 2k).  The car starts right up when this happens.

Will suggest both to the tech.

Radio Suppression relay?  Does it make a difference (symptom wise) if the radio isn't working?  No power, no nothing.  The prior owner had difficulty with the radio (came on really loud, like a speaker problem).  The radio isn't working at all - he removed his sirius satelitte feed.

Jeff

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Followup To

Question -
Hi Ray,

Thanks in advance for your advice (I'm an Allexperts expert in some other categories.)

I just came into the possession of a 93 940 Turbo Station wagon.  155k on the car.  Just had it inspected, passed, everything "looks" great according to the mechanic.

Except it stalls out while driving.  I can't tie it to a specific symptom...

I'll be driving, press the gas, and the car will choke and stall.  Sometimes it just chokes a little...but mostly it stalls out.

It doesn't seem to be tied to a particular amount of time driving nor to a time a day (such as if it was hot.)

Uphill right turns *seem* to be more likely to cause a problem - but then again, I've had it stall just as I move from a stoplight on a flat road.  It doesn't seem to happen (thank god!) on highways; more street driving.

I'd give you a code if I knew where/how to find them.

The car sat for about 3 months unused...I've added a fuel injection cleaner and a water remover (to the tank).  I'm waiting to see if these help.

I'm sure it has something to do fuel system or electrical system.  I have a good foriegn car mechanic, but *not* a volvo expert (he is very good though.)  I was wondering what direction I might point him in beyond "look at the fuel/electrical system"

Thanks,

Jeff

Answer -
Jeff,
Fuel pump relays and radio suppression relay cause these stalling problem. Is the car stalling more often with the fuel lower than half? The in tank pump or hose off of it maybe broken causing a loose of fuel at times. You could have you tech ride around with a fuel gauge to see if you loose fuel pressure when this happens. When it dies does the tach dive all the way down?

Answer
Jeff,
There is also a power stage for the ignition system it is mounted to the inner fender well by the battery and that also causes a no start or stalling.
Radio suppression relay is just to power up the injectors and provide them protection from power surges due to other electrical items being use. If the relay is dead then no power to the injectors.