essexRSTSouthend

Hey all.

I've got a brand new battery,alternator,alternator cable and battery cables.all earthing's cleaned and check 3 times!

The car is just running on the battery... car stops running and bang the battery flat.on charge now.Any help be great.As really running out of ideas and hope on this car.

xr2wishy

iTrader: (2)

is the battery light coming on when ignition is first turned?
if not, that could be the problem.

essexRSTSouthend

Hey xr2.

No it doesnt come up.Im guessing thats the blue wire from the alternator faulty?

This easy to get to?

project rs

or the bulb has blown check it for a known working one as that kicks the alternator into action

essexRSTSouthend

a blown bulb can cause it too..

Moonie

Yes, a blown charge indicator bulb can cause the alternator not to charge as it is part of the trigger circuit. The alternator will start charging when the engine rpm is increased.

Take the blue wire off the alternator and ground it (hold the terminal against the engine block or alternator body) Does the charge warning light come on when the ignition is turned on?

Yes - trigger circuit ok (fault with alternator, battery wiring, earth or battery).

No - trigger circuit open circuit (break in trigger (blue) wire, blown charge indicator bulb or +12V feed missing to bulb).

A common fault is the trigger (blue) wire breaking below the radiator.

essexRSTSouthend

Thanks for that helpful advice mate.going to try that.

essexRSTSouthend

a update here.

Right checked the bulb and all the others bulbs and none of them are blown.

The battery at the moment is sitting at 12.60volts.When started it sits around 11.80 volts.When increasing the revs should the volts increase.As they did at one point but now they just sit around the 11.80volt mark.

Must point out that we also made the alternator belt tighter and gained us a extra few volts and also joined the blue wire directly to the other blue wire,which also helped.Also note that the battery was left on charge from yestoday until 2pm today and still had a bit to go before fully charged.So the battery back on charge now and going to measure the volts again tomorrow...

Im thinking maybe this new alternator is faulty or the blue wire is playing up along the loom.But which side does the blue wire go behind the dash,left or the right..
Battery light still not working even with finding no faults as of yet..

Sorry for the essay.Trying to give you as much info as possible just in case any of you can help futher.

MunkeyboyRS

I had a major prob like this took me ages to sort it, turn out it was the rear heated window replay was fucked, so it was always on. go mad on your car with a voltmeter test all fuses and relay, headunit if you got one any thing you cant get to.

essexRSTSouthend

Funny you should say that,as my wires on the right side of the boot when you open it has a slight cut in it.Don't look healthy.Did you say the relay was broke?

I think i will have to go mad one way or another,volt meter here we come lol.

RobertM

Did you check the circuit like Moonie explained? This is the first thing you should do. Don't worry about shortcircuit, this is impossible.
If this check is OK, find someone who has a ampmeter (clamptype) and let him check if there is a current flowing in the B+ wire (whit running engine). Could be the alternator is working but can't keep up, because of a large current draw like rearwindowheater. Also check the voltage at alternator B+ and battery. If there is more than 0.5 volt difference the cable could be broken between alternator and starter/battery

essexRSTSouthend

Hey Robert.Im still trying to see what wire is the alternator one behind the clocks...May have to get a bit messy with wires today..

Yes already checked the volts on the alternator,could'nt see any change in voltage to what the battery was reading.

All the wires for starter and alternator are new.Which keeps me pointing at the wire in the loom.wish me luck

Moonie

Have you grounded the blue wire at the alternator as i said? If the bulb is ok then there IS a break/open circuit in the trigger (blue) wire somewhere. From memory i think the trigger wire has an inline diode down below the radiator. Would be worth checking the connections on this and the continuity across the diode.

Moonie

Right as i am bored and theres nowt on TV i have done you a quick diagram



As you can see the charge circuit is basic and a few simple tests (as i have put above) will pinpoint the problem.

Note - i have used the colour Red between the battery, ignition switch and charge warning light to show it is a positive feed - i cant remember what colour this wiring is on the Mk4 Escort.

essexRSTSouthend

Thanks that.Was handy.

I've checked the feed to the blue wire and has power.Even made a wire up just for test purpose and was working.

Yes the blue wire grounded to the alternator.

I did notice i was only seeing a max of 12.60volts coming out of the alternator..
Battery read 13.80 before starting.

Will keep checking.

Moonie

So when the blue wire is grounded the battery light comes on?

If your seeing 13.8v at the alternator output and only 12.6v across the battery it means its "dropping" over 1v in either the cable between the alternator and the battery positive terminal or the battery to engine earth cable.

Try this -

With the engine running touch one end of the multimeter on the positive output terminal of the alternator and the other probe on the positive battery post - ideally you want to be seeing around 0v with a max of around 0.3v?

Then touch one probe on the engine (clean metal part or the alternator body) and the other probe onto the battery negative terminal. Again you want to be seeing around 0v with a max of around 0.3v?

Readings above 0.3v indicate excessive voltage drop - poor/dirty connections, loose connections partially broken wiring etc.

essexRSTSouthend

Hello Moonie.

Thanks for the advice and helping me.

We tried this way you said.Hardly anything came up.What we did notice was when i changed to my old alternator i could'nt get anymore than 1volt!!

So i know my old one needing changing anyway.So seem the newish alternator may need changing for another one.

The battery light hasnt came on once yet.

Moonie

If the battery light isnt coming on when the blue wire is grounded at the alternator end then you need to find out why berfore replacing the alternator. If there is a problem in the trigger circuit then a good/working alternator wil still not charge.