Hey,

1990 740 GL. Regina. Has issues starting when below 20 degrees.

Good battery. Strong starter.

BUT

I measured the volts when it was being started and it was 40 degrees out... seemed to be dropping to around 10.5 from a 'float' voltage of nearly 13 and a running voltage of nearly 14.

I can only imagine the voltage would go lower when it's really cold, like below 20, which is when I start having issues.

Is 10.5 volts too low? Could it make the computer get squirrelly such that it wouldn't be able to start? Somebody meantioned this in some other thread and I can't find it or the figures they used.

If it is too low, what's the fix? The battery is a good one, maybe a bigger one would help though?

I see exactly what you are saying. Not possitive but most electronice IC's operate down to 5 Volts so I don't the V drop during cranking will make the Computer cranky.

In fact on another vehicle I had, I had to keep programming my Radios pre selcts because on cold days, the radio would lose them after Starting the vehicle. The battery was on it's last leg. The Starter cranked slow. But it still started.

So I hear you but I would look elswhere.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

Is the starter not spinning/cranking it as fast when cold? Or is it cranking fine, but just not starting.

If it's cranking fine when cold, then I'd look at:

1) spark wires and/or plugs
2) injectors

jp
--
Jeff Pierce (Post back with your results... it's what makes this forum work.)

IMO 20 CCA isnt going to make much difference BUT id be running a minimum of 380 and preferably higher like 460CCA etc.

Voltage drop while cranking is not unusual and I cant see 10 ish volts being a major issue however there are a few things to bear in mind.

A worn starter motor (Tired brushes or shagged solenoid) which may well work fine during warmer months, will have a huge impact on how much it needs to operate correctly at colder temps and may well be dragging the voltage lower than 10 volts and possibly cranking slower which will make a difference.

Id try the other battery (Fully charged) or get a bigger unit and perhaps get your starter checked and/or rebuilt if it is of unknown condition.

Cheers,
Tony

Here's the deal:

The battery I've been running all winter is a type 84 that used to go in my wife's Odyssey (long story as to how I would up with an extra). And it's fine.

But I threw that one in there as a stopgap about 2 months ago, fully intending to put in a new battery specific for the Volvo. And I bought a 740-specific one, but never put it in, since the Odyssey's battery seemed to be working fine. And the brand new Volvo-specific battery just rode in the trunk and gave me the occasional jump start.

BUT

I just examined the Odyssey battery, and it has about 20 fewer cold cranking amps than the Volvo one. And if this hypothesis is correct, and I'm getting a voltage sag during cranking on cold mornings that's making the computer lose its tiny mind, that could be the root cause. So I just put the beefier battery in. 20 more CCA is 20 more CCA.

Maybe it will work and maybe it won't, but it's something to try, at least. More power certainly won't hurt.

The battery should read 12.6V with the car off

You can check each cell of your battery with a hydaumeter (can't spell)..
that will tell you if there is a bad cell/s, or if it's OK

Don't bother meauring battery volts while cranking , if the engine is spinning
OK forget voltage readings until it starts and then you should see about 14.1 volts at the battery (The alternator charge voltage)

Bill