Subaru Forrester starting problem

[NDA]

I had a problem starting a Forrester this morning from cold. Engine turned over rather weakly and wouldn't fire up.

I jump started it from a (fully charged) portable battery thing and, with a little feathering of the throttle, it started. Thing is, it still turned over rather pathetically even when jumped.

I'm not hugely mechanically minded (I can do everything that doesn't involve a spanner).

The Subaru is just over 3 years old.

Any thoughts or is this simply too vague to diagnose?

Thanks.....

[fluffnik]

NDA said:

Any thoughts or is this simply too vague to diagnose?

Bad earth or loose connection?

Prime suspect would be the earth bond between motor and body.

[ScoobieWRX]

Car seems too new to be having starter motor problems already.

+1 for bad earth, just check all the cable connections to the starter from the battery, and the earth from the gearbox housing.

[NDA]

Thanks guys, I'll check that out in the morning.

I assume this is not the battery terminal connection but where the battery is earthed to the car somewhere?

[fluffnik]

NDA said:

Thanks guys, I'll check that out in the morning.

I assume this is not the battery terminal connection but where the battery is earthed to the car somewhere?

It could be them too.

There should be a fairly direct feed from the battery +ive via a solenoid(relay) to the starter and an earth bond from the -ive terminal to the body then the body to the engine/gearbox.

The body to driveline connection gets most vibration so it's most likely to loosen or fatigue, but any loose connection will eat cranking amps before they reach the starter.

Best of luck!

[NDA]

Thanks again.........

I will be checking this out tomorrow. It's my wife's car and shall be claiming this knowledge as my own invention you understand.

"It's probably a bad earth dear" will be said in a profoundly nonchalant manner as I stride purposefully towards the bonnet with a suitable tool in hand.

"But how do you know?" she will ask.

"Because, my dear, I have testicles. It is our job to know. Now stand aside and be about your business."


Perhaps I should do this AFTER fixing the problem.

I shall report back.

[fluffnik]

NDA said:

I will be checking this out tomorrow. It's my wife's car and shall be claiming this knowledge as my own invention you understand.

"It's probably a bad earth dear" will be said in a profoundly nonchalant manner as I stride purposefully towards the bonnet with a suitable tool in hand.

"But how do you know?" she will ask.

"Because, my dear, I have testicles. It is our job to know. Now stand aside and be about your business."

Hope it goes well.

[AstonZagato]

Anything that might be causing a drain on the battery? Leaving something charging - mobile phone - over a number of days? After 3 years it could be a knackered battery - early for it to go but you'd first find it in cold weather.

[NDA]

It's minus nine million outside - but despite this I donned my bicycle repairman's outfit. I've tightened the earth on the car body (I assume there's only one), the battery terminals and the one on the solenoid.

It still feels like there's not much 'woof' when it turns over, but then again I'm not that familiar with this car.

Let's see.

More later in this thrilling episode of 'My Subaru Doesn't Start Quite The Same Anymore'.

[ScoobieWRX]

Good point about the knackered battery. If it's a sealed one there's nothing you can do, however if it's not sealed like mine you can just unscrew the cap off each cell pop a couple of battery tabs in each one and then top up with distilled water.

Did that job on mine a while back and it's been spot on ever since, even on the cold frosty mornings we've had recently it has plenty of juice in it to start the car.

[NDA]

I've got a battery tester (that does amps), I'll give it a whirl and take a look.



Right.....

Tested the battery. It's a tester that has a heating element inside it to 'load' the battery. It's reading something like 300 'cranking amps' at minus 2 outside and 12v.

Looks like it needs 520 according to a brief scan on t'internet.

New battery time mebbe.

[/footnote]

Edited by NDA on Sunday 28th December 11:27

[AstonZagato]

Oh yes. Armchair Mechanic rides to the rescue...

[Hybrids]

NDA said:

I've got a battery tester (that does amps), I'll give it a whirl and take a look.



Right.....

Tested the battery. It's a tester that has a heating element inside it to 'load' the battery. It's reading something like 300 'cranking amps' at minus 2 outside and 12v.

Looks like it needs 520 according to a brief scan on t'internet.

New battery time mebbe.

[/footnote]

Edited by NDA on Sunday 28th December 11:27

Before you dismiss the battery, just going back to your tester.
Load testers are only accurate on a charged battery & most hand held load testers only create a 100amp load.
How long did you hold the load on for and what did the voltage read before, during and after ?

There are conductance testers taht will simulate a load test and give a CCA (cold cranking amp) reading for your battery without a load and can be done on partially flat batteries

[AstonZagato]

Oh no. Armchair mechanic trumped by someone whio actually knows something...

[buckman63]

Just to add on a very basic level, and obvious to some that during very cold weather engines are much "tighter" on first start up, therefore produce somewhat lower cranking speeds, and also its general that during the colder/shorter days the occupant generally has all the electrics switched on much longer, heating, lights etc therefore the battery works hard to keep up its full charge. If this time of year your day generally consists of short trips, perhaps the battery just requires a boost from a charger overnight. Just a thought !

[NDA]

The tester recommends a 10 second load period. There's also a graduated step for cold temperatures. I can't recall what the dial read before and after the load - the needle dipped and sprang back, that's all I remember officer.

Maybe a new Subaru then?

[Hybrids]

Before testing make sure you have more than 12.5volts in the battery.
When you hold the switch for the 10 seconds it should drop to no less than 9volts.
When released it should recover back up to over 12v and then increase to over 12.5v.

If it continues to drop beyond 9v on load it's more than likely a duff battery or it wasn't fully charged for the test.
If it's the std 100amp load type 10 seconds isn't really enough, so if you are happy doing so a 15>20seconds load would be more relevant to your battery size.

3 years isn't long for a battery life, we generally see a 7 years life span, depending on the useage as mentioned above, short stop start journeys, having all the toys on etc etc.

HTH's

[NDA]

Hybrids said:

Before testing make sure you have more than 12.5volts in the battery.
When you hold the switch for the 10 seconds it should drop to no less than 9volts.
When released it should recover back up to over 12v and then increase to over 12.5v.

If it continues to drop beyond 9v on load it's more than likely a duff battery or it wasn't fully charged for the test.
If it's the std 100amp load type 10 seconds isn't really enough, so if you are happy doing so a 15>20seconds load would be more relevant to your battery size.

3 years isn't long for a battery life, we generally see a 7 years life span, depending on the useage as mentioned above, short stop start journeys, having all the toys on etc etc.

HTH's

Yes, very helpful thanks. I'll have another test tomorrow. When I tested it before it was reading 12 volts (maybe 12.5, I didn't look that closely) and when I hit the switch and held it, the reading didn't drop that much. It also fully restored to its previous reading when the switch was off. I shall try 20 seconds or so tomorrow.

I suspect Mrs NDA had left an interior light on and possibly drained the battery...

Could you have a healthy 12.5v reading but reduced cranking amps?

[Hybrids]

NDA said:

Could you have a healthy 12.5v reading but reduced cranking amps?

Yes

But...
It would normally manifest itself as a dead cell which would show up in the drop (discharge) test
Ideally you would also perform a Hydrometer test (providing it's got accesible cells) to check the specific gravity of each cell, ideally looking for a max. varience of 10% across the 6 cells.

Another posibilty of correct voltage yet no cranking amps are overcharged or cycled batteries where the electrolyte has evaporated, but only in severe cases.

[NDA]

Hmmm!

Well it's a sealed battery, so I can't do an individual cell test.

Just out of interest (as you are a specialist), what is it that gives a battery it's 'woof'?! By that I mean the amperage needed to deliver a sufficient depth of power to crank an engine? Is it simply all cells performing adequately, or something else?

I've always assumed it was some mystical mojo that only new batteries had - but suspect that technology does not actually revolve around voodoo.