ok, battery is a brand new varta, alternator is putting out 14.4 volts, 14.2 with the lights on. It's been fine since monday when the batt went in and now em gets home and it wont start. The stereo turns off if the revs drop below 5000rpm and the wipers are slow as hell.

It started first spin when she got in it at college, and within 8ish miles the stereo was cutting out. Now it's home the ignitions on fine and the battery light wasn't on whilst it was moving.
The starter turns over really slowly, nowhere near quick enough to start it. Barely enough to compress the engine. All earthing points are perfect, I redid them all the other week, bare metal to bare metal and the cables are in good condition. The amp power lead is intact and hasn't blown the fuse.

I'm at a total loss, wtf is going on? where is all the power going?

Jon+Em

when you are parked up with engine off and nothing electric on.put a multimeter over the battery to see if the volts are constant or if theres a drain

was constant when i checked yesterday. didn't go down even after starting. battery seems full though, as the ignition wouldn't come on before, and the battery light was always on, even when the engine was running.

Jon+Em

checked the connections on the alternator?breaking cable?

nope it looks fine. checked that when we replaced the alt on saturday.

Jon+Em

well i think you need to start continuitly checks on the ignition circuit if your getting ignition lights and no ignition

no we have ignition, but the battery wont turn the starter fast enough for it to fire up. it just turns slowly. like the batteries flat, but i don't see how it can be? if the alt is healthy then why is the battery not charging, and if it is flat why is there no battery light?

Jon+Em

have you checked the starter isnt seizing

how do I check that?
That wouldn't drop the voltage whilst the engine is on though?

The battery light doesn't mean low battery - it means altenator not charging! Do as custard says and check with multimeter!

also remeber part of the ignition wiring goes to the starter so check the big red cable as well

But the battery light isn't on. and the alternator IS reading 14.4 across the battery when the engines on. so it should be charging shouldn't it!

Jon+Em

check the main battery to chasis earth. sounds to me like its dodgy

project-cinqy said:

But the battery light isn't on. and the alternator IS reading 14.4 across the battery when the engines on. so it should be charging shouldn't it!

Jon+Em

Click to expand...

theres no point saying the car is/should be charging as its obviously not if it cant supply enough charge

but what I don't understand is why, if the alternator is putting out 14.4v, which I'm reading across the battery and using any piece of bare metal i can reach (engine, strut bolts, actual earth points, and numerous other bolt heads,) as earth, is it not charging the brand new battery? It's really wierd.

and the main earth is ok, checked it the other week, and again at the weekend when the alt was swapped just to be sure.

I'll go over all of the earths tomorrow if i can get it to start!!! Run the meter over everything including the amp and see what I'm getting.

This is just so odd, as everything I can think of has been replaced or checked, and it all seems ok.

Jon+Em

yes but for example a broken wire that makes partial contact can lose contact under drive but be fine at idle under testing.you cant always take things as absolute

Thats a very good point. will have to wiggle stuff and see what happens. Thanks guys!

ok, think its done. took bloody hrs heres the list of things done.

took out alt and put new belt in,

checked brushes in both alts. the old one was crap, so have put the good brushes from the squeeky alt into the old alt.

cleaned and derusted all earthpoints throughout the car. main chassis earth was ropy, as was the one on the thermostat.

wd40'd all electrical connectors and then replaced alt. Tensioned the belt to just over 5mm.

checked voltage with every electrical item on, including reversing and brake lights, stereo and the washers, and it reads around 13.7volts, so pretty healthy now I think. It reads 14.4 with just the engine, and 12.7 with just the battery. Plus the squeeking noise has totally disappeared!! yay!!

Also put the carpet i've had kicking around for ages into the boot, so the sub sounds a lot better than it did with the crappy rubber mat with holes in (plus it moves around less too.) And I tided all the cableing at the same time. Also swapped the polarity on the sub leads so it's in phase with the rest of the car beginners mistake I know!

might get it washed and photo'd (in daylight this time) this weekend if the weathers ok!!

Thanks for all the help people, it's much appreciated!!

Jon+Em

good news though your sub should be fully anchored and the carpet wouldnt matter?
im guessing yours isnt?

no it isn't anchored as we don't have the cash at the mo, thats a job do in a week or 2 when we have a bit of spare cash.