Been having a problem with my Fiesta Zetec S for a while.

If I don't use the car for a few days it won't start because the battery is flat.

It had a new battery about 9 months ago so I don't really suspect that.

I put a multimeter on the battery today and when running it's showing 14 point something, so I guess alternator is ok?

Had a check round engine bay as well today and discovered that the earth strap from the engine to the bulkhead has snapped.

Please forgive me if this is a really dumb question but, would the broken strap be causing my problems?

Any help would be greatly appreciated.

 

well you need to replace the earth strap anyway; so replace it and see if that solves the problem. Was the strap completely snapped??

it well be the battery has seen better days; putting a multimeter on it while its running will rule out alternator, as anything above 14 volts is OK

what the battery volts after a few days before you attempt to start it?

If its not the earth strap, then i suspect a new battery is needed or you have a battery drain going on somewhere

 

I doubt the earth strap would be doing it to be honest. Mine was completely off for a fortnight on my Puma and it didn't make a blind bit of difference.

There has to be a reason for your battery draining (if it is the battery) So it's either at fault of you have a drain somewhere - dodgy aftermarket alarm, light etc.

I've had mates that have bought a battery that just won't hold a charge. The tests all show it to be fine, but when swapped for another battery all was well. Just because your "new" battery is only 9 months old, don't discount that being the culprit. Get it swapped under guarantee.

Good luck.

 

As an update, I have replaced the earth strap, which had snapped off completely.

Took the car to where I brought the battery, they tested it and said alternator is ok and battery is also fine.

Since the car has been playing up I have removed the bulb from the boot light and switched off the interior light so that it can't come on.

I've also checked the wiring on the stereo as it has had a different one put in, whoever put it in used the proper loom and all looks fine.

My girlfriend, who uses the car the most, told me today that a dash light has come on a couple of times recently.

Having slapped her a few times I have managed to discover that it's the door ajar warning light.

So it's probably a dodgy micro switch somewhere? The alarm hasn't been false alarming and all interior lights are disabled so would this be the cause of my possible battery drain?

 

It sounds as though it is possibly the alternator.
Just because it charges perfect does not mean it is not faulty!!
The alternator contains a thing called a regulator rectifier, the reg part is what regulates the voltage supplied to the battery, the rectifier part converts the pos and neg pulses given off by alternator to just positive on which the car works.
This is done by rectifier diodes little electrical one way valves, these can leak, even when brand new, and so allow current to travel from the battery to the alternator so draing the battery when the engine is off.
To eliminate simply leave a few days with the alt or battery disconnected.
The problem is leaky diodes will rarely show up in tests, as alt still charges 100% perfect.
The earth strap will not cause a drain, but does need to be there anyway.
tabetha

 

Thanks tabetha, I shall give this a go.

 

It's been nearly two months since my original post but things are still not sorted. I'm now getting desparate and really p***ed off.

As an update, I changed the alternator for a new one and have been over the car looking for any obvious wiring problems. To be honest this was probably a waste of time 'cause I don't really know what I'm looking for. With work commitments etc that's all I've managed to achieve.

I did leave the alternator disconnected for 6 days and the car started first time after reconnecting, so I assumed the alternator regulator was at fault, hence the new one. But obviously it wasn't.

I fully charged the battery after fitting the new alternator and started using the car again, it lasted for only two days before it wouldn't start again.

In those two days I noticed that the cooling fan came on really quick, (after about two miles), and just stayed on for the next 10 miles until I switched off. I've checked the cooling system and all is o.k so maybe dodgy fan sensor or that's where my short circuit is???

I'm now assuming that I've most certainly got a short circuit somewhere but how the hell do I test for one????

Any help or advice would be really, really appreciated guys as I'm now getting a little frustrated.

 

have you tried a drain test on the car?? you should have a drain of no more than 0.3amps.it sounds like you have a drain on the battery causing it to discharge.if you have a drain then you could pull each fuse out until the drain reachs the set point of 0.1/3 this is for the led for the pats flashing and keeping the radio stations etc. hope this helps

 

No I aint. To be honest Matt, I haven't got a clue how to do one.

Can you give me a bit more info on how to do it?

Cheers mate.