Alternator Problems

[Guest wrights]

Hi All

 

I need some help with my alternator, it’s not charging correctly. New build just failed 1st SVA.

 

Spent all day today trying to find the problem, seem to be going around in circles now

 

When I 1st wired this up I had trouble with the ignition light, it would not go out, after reversing 2 leads all looked correct and the light would go out when engine started, at the time I checked the battery with a meter I was showing charging. 14.5 + volts

 

Whilst having a remap my battery started to go flat and on the PC screen it was showing 11.5 volts and dropping, then it would start charging for a few sec's then stop again, hence battery went flat.

 

I have been checking the wiring, my alternator has + B + D and W terminals and I have re wired as per rhocar diagrams

 

I have connected 2 x brown to +B,

+ D a switched live and W the ignition light via a + 12 volts supply.

 

My ignition light is on when the key is off, when I turn the key it goes off, start engine and light comes on and battery is charging ok, light goes out and battery stops charging, then light comes on and battery starts charging. This can happen at any time. When the light comes on the engine rev’s drop slightly as if a load has been put on some where and when the light goes out the rev’s increase slightly

 

I have had the alternator checked by a company and all is ok.

 

If I disconnect the + lead on the battery, put 1 lead of my meter to earth and the other on the + wired terminal that’s disconnected from the battery I have no reading., switch the ignition key on and I get a reading, is this correct or is this my problem, power leaking to earth. All my lights, indicators ect all work fine and this is my only wiring issue.

 

Hope some one can point me in the right direction

 

Cheers

Stephen

[Guest Jabberwocky]

Right then matey, I had the same sort of problem as you not so long ago. (albeit with a pinto) there are 3 wires on the alternator.

 

1 earth

 

1 wire to the dash light /12v

 

1 wire that is the output from the alternator to the battery

 

what I did in the end was to prove that the alternator was working and that it was a problem with the dash light wiring I shorted out the alternator out put wire to the dash light/12 volt terminal. then disconnected the battery, if the alternator is working then the engine should keep running. if the engine dies then there is a problem with the alternator or it's connection to the battery terminal.

 

I have heard that some people do not like the idea of disconecting the battery with the engine running (make sure the +ve batt feed does not touch the bodywork) as it might damage the alternator. I personally can not see how that would happen but I would bow down to someones experiences of that.

[Longboarder]

What alternator are you using? Can you draw a diagram of the wiring as you have it now.

 

Nigel

[Guest wrights]

What alternator are you using? Can you draw a diagram of the wiring as you have it now.

 

Nigel

 

Hi Nigel

 

Not sure of the alternator make but I brought it from the parts department at westfield kit cars, I used thev NW area replacement alternator wiring for a rascal alternator as a guide,

 

I have got 2 x browns on terminal +B

switched live on +D

live on one side of the ignition warning lamp to W.

 

Wired this way the lamp is on, turn key and lamp goes out, motor starts and lamp comes on, batt showing charging, lamp goes out and batt stops charging.

 

Turn key off, engine runs till I disconnect the switched live lead to the alternator, found this out sunday.

 

I have taken the alternator off the car and taken to a local company who have tested it and said its working fine

 

cheers

Stephen

[Longboarder]

Two browns to B+

Sounds like Vicky green loom. These should go to the Pos battery terminal, either direct but can detour via the starter solenoid terminal if that's more convenient/practical for tidy wiring. Obviously there is also a hefty cable from battery Pos to the starter solenoid.

switched live on +D

live on one side of the ignition warning lamp to W.

Try connecting nothing to the W terminal. Ignition warning light has switched 12V supply to one side of the bulb and connect the other side of the bulb to D+.

Pic of the alternator would be helpful to see what sort it is. When posting a problem it's always a good idea to put in as much information as possible about the components involved. Make and model of alternator, loom, dashlight (led like bright 7 or sierra dash with tungsten bulbs) etc.

 

Nigel

[Guest wrights]

Sounds like Vicky green loom. These should go to the Pos battery terminal, either direct but can detour via the starter solenoid terminal if that's more convenient/practical for tidy wiring. Obviously there is also a hefty cable from battery Pos to the starter solenoid.

Try connecting nothing to the W terminal. Ignition warning light has switched 12V supply to one side of the bulb and connect the other side of the bulb to D+.

Pic of the alternator would be helpful to see what sort it is. When posting a problem it's always a good idea to put in as much information as possible about the components involved. Make and model of alternator, loom, dashlight (led like bright 7 or sierra dash with tungsten bulbs) etc.

 

Nigel

 

Hi Nigel

 

Spoken to Westfield and the alternator is a ford replacement part for a Escort mk 4 or mk 5 which was fitted to the zetec engine in that make, Westfeild have no idea who has made it and no identifcation on the alternator. Loom is Vicky green, just a normal single dash ignition light and individual dials.

I will try tonight, what you have recommand and post a pic of the alternator.

 

Thanks

 

Stephen

[Guest wrights]

Doc1.doc

Hi Nigel

 

Spoken to Westfield and the alternator is a ford replacement part for a Escort mk 4 or mk 5 which was fitted to the zetec engine in that make, Westfeild have no idea who has made it and no identifcation on the alternator. Loom is Vicky green, just a normal single dash ignition light and individual dials.

I will try tonight, what you have recommand and post a pic of the alternator.

 

Thanks

 

Stephen

 

Hi Nigel

Found this photo on my memory stick not the best, if no good will take one tonight and post tomorrow

 

Doc1.doc

 

cheers

Stephen

[Guest wrights]

Doc1.doc

 

Hi Nigel

Found this photo on my memory stick not the best, if no good will take one tonight and post tomorrow

 

Doc1.doc

 

cheers

Stephen

 

Hi Nigel

 

Completed wiring change last night, turned key, lamp on, started engine lamp off, battery charging 13.5 volts, 45 seconds later battery volts dropped to 12.5 volts. Stopped engine, turned key, lamp not on this time, start engine, battery reading 12.2 volts. Stop engine.

 

find attached photo's of alternator

 

Cheers

Stephen

Alt.doc

[Longboarder]

I don't recognise that alternator Stephen. I'm a bit suss about the wires you have used. The wire from B+ to the battery should be more like 4.5 or 6mm square. That looks like something you pulled off the old kettle or hoover. I would still use just B+ and D+ and replace the wire with something much more substantial. Also solder or use proper crimped connectors. Those look like the squeezy plastic ones which are unreliable.

 

Nigel

[Graham B]

I'll second that.

 

The B+ wires feed all the alternator output to charge the battery , run the motor, , lights , wipers etc etc. .. Get some proper lead, not 3 core from a 3 Amp electrical appliance.

 

D+ will go 12 V once the alternator has kicked in and put out the dashboard light ( 12 V on either side) . forget W..

 

Graham B

[Guest wrights]

I'll second that.

 

The B+ wires feed all the alternator output to charge the battery , run the motor, , lights , wipers etc etc. .. Get some proper lead, not 3 core from a 3 Amp electrical appliance.

 

D+ will go 12 V once the alternator has kicked in and put out the dashboard light ( 12 V on either side) . forget W..

 

Graham B

 

 

Hi Nigel/ Graham

 

I have extended the small brown on the loom provided with the same size cable, the green /yellow is just sleeving over the switched + lead which I was told on this forum to put to any white or green lead and I used the same size wire as the lead I was connecting too, if this needs to be bigger then I can change but it looks like I will not be using that lead, the large brown has not been altered and is the original in the loom. Again the wire from the ignition lamp has been extended with the same size cable as in the loom and at present has a switch live going to +D via the ignition lamp.

I have not used 3 core cable from an electrical appliance to do any wiring on this car. Re the connections to the terminals I have used I can change them no problem.

 

Do I need to upgrade the switch live lead that I got on the +D to the ignition lamp?

 

I have moved the issue on all works fine (when wired as above) when you 1st start but once everything warms up it stops working, including the ignition light not coming on when key is turned, going to get the alternator changed as I think the regulator is packing up once it gets hot.

 

Just need to check as I am not sure, would I expect the battery to stay charging all the time at 13 .5 volts or would you expect it to drop when the battery is re charged to say around 12.5 volts.

 

thanks for your help

 

Stephen

[Longboarder]

Sorry Stephen, I know it's not the old lead off the hoover. Wire to D+ can stay as it is. It's only the main connection wire, B+ to Battery positive terminal that needs to be heavyweight. I'm wondering if having such lightweight wires is giving a problem with resistance and voltage drop and is part of the problem. Also it looks to me as if one of the wires is brown and one black. Check continuity to make sure they are the correct wires and do go back to Batt pos either direct or via the starter solenoid and nowhere else.

 

With the ignition off you should read about 12.5- 12.7v across the battery posts with your meter (set to volts). If you pull one of the terminals off, and measure between it and the terminal it has come from, still with the ignition (and everything else) switched off there should be no current flow and there should still be 12.5-12.7 between the two battery posts. Put the terminal back on and start the car. With 1500revs or above you should now find about 13.7-14.2v across the terminals. It should stay at that level for as long as the engine is running and pretty much regardless of what additional equipment is then switched on. So if you put on lights, wipers and heater the alternator output should automatically adjust to compensate for the load and maintain the voltage.

 

Nigel

[Guest wrights]

Sorry Stephen, I know it's not the old lead off the hoover. Wire to D+ can stay as it is. It's only the main connection wire, B+ to Battery positive terminal that needs to be heavyweight. I'm wondering if having such lightweight wires is giving a problem with resistance and voltage drop and is part of the problem. Also it looks to me as if one of the wires is brown and one black. Check continuity to make sure they are the correct wires and do go back to Batt pos either direct or via the starter solenoid and nowhere else.

 

With the ignition off you should read about 12.5- 12.7v across the battery posts with your meter (set to volts). If you pull one of the terminals off, and measure between it and the terminal it has come from, still with the ignition (and everything else) switched off there should be no current flow and there should still be 12.5-12.7 between the two battery posts. Put the terminal back on and start the car. With 1500revs or above you should now find about 13.7-14.2v across the terminals. It should stay at that level for as long as the engine is running and pretty much regardless of what additional equipment is then switched on. So if you put on lights, wipers and heater the alternator output should automatically adjust to compensate for the load and maintain the voltage.

 

Nigel

 

Hi Nigel

 

The brown wires are the loom wires, the black one is connected to the smaller brown, I changed the colours so I new what cables went where but it's the same size wire, the larger brown was long enough to reach so that did not get extended, also I have checked the larger brown wire and it goes back to the + lead on the starter motor then goes up to my battery via a chunky cable, so the brown wire needs to be larger then, what size, same as the cable that feeds the battery to the starter motor or smaller.

 

see attached events from last night, light stopped working when it had been running for some time and would not light again till the engine was cold.

car.doc

Cheers

 

Stephen

[Longboarder]

That all sounds correct Stephen. I think when the flashers are on the alternator charging circuit can't respond quickly enough to even out the flashers. Sounds like the battery is good and the charging circuit is also good. I suspect something is overheating and cutting out in the alternator, possibly due to the resistance in the brown lead as it's too skinny. I would replace with 3mm square minimum or 4.5mm square cable. But at the end of the day it may be an alternator fault.

 

Nigel

[Guest wrights]

That all sounds correct Stephen. I think when the flashers are on the alternator charging circuit can't respond quickly enough to even out the flashers. Sounds like the battery is good and the charging circuit is also good. I suspect something is overheating and cutting out in the alternator, possibly due to the resistance in the brown lead as it's too skinny. I would replace with 3mm square minimum or 4.5mm square cable. But at the end of the day it may be an alternator fault.

 

Nigel

 

Hi Nigel

 

I have rechecked wiring ect over the weekend and used beef up cable but no difference, basically all works if everything is cold, red light on, charging ect, will charge for around 5 mins, turn off, turn back on, no light but voltage at alternator on lead 12 volts, touch earth to lead at alternator end and light comes on, Looks like regulator is faulty, if I take that lead off I see a small voltage on the alternator + D terminal

 

Will get changed and update you, thanks for your help

 

Stephen