Alternator advice

[skyhigh123]

I'm in SW France at the moment.

I returned from a 100 mile trip and switched off. I happened to need to restart the engine and there was barely enough power to turn the engine though in fact it did start and proceeded to run normally. I switched off again and this time there was not enough to start the engine. I gave the battery half an hour's charge with my low powered 4 amp charger and the engine started successfully and ran normally. The red "charge" light was not illuminated while the engine was running. The alternator belts are fine.

Tests with a multimeter showed the following- Engine stopped 12.5 volts at the battery, engine going 12.1 volts. I also checked the voltage at the alternator and got the lower figure. Having read the fact sheet I tried the suggested test for a "field voltage" and was unable to detect a magnetic field.

Questions:

Why no red light?

Is it ok to start the engine, disconnect the battery and test for voltage at the alternator to see if it is producing any power. (I'm no electrician but I'm assuming that the low reading I'm getting at the alternator is actually the battery output.)

Do the fuses have any role in the charging circuit-I'm thinking of the main 100 amp fuse which I haven't tested as I gather it's a bit of a fiddle to remove.

This "field voltage"-the next step is to identify the wire (the one normally labelled "F" according to the fact sheet.) and test for 12 volts. I can't see any "F"-can someone describe which is the relevant wire please?

If I find the wire, test the "field voltage" and find no reading, confirming the lack of a magnetic field, what's the procedure for reestablishing a field voltage-again is there a fuse involved?

Any other suggestions before i go and test my french technical vocabulary at a garage?

Thanks in advance for any advice

Tony

[mikeonb4c]

Tests with a multimeter showed the following- Engine stopped 12.5 volts at the battery, engine going 12.1 volts. I also checked the voltage at the alternator and got the lower figure. Having read the fact sheet I tried the suggested test for a "field voltage" and was unable to detect a magnetic field.

Questions:

Why no red light?

Is it ok to start the engine, disconnect the battery and test for voltage at the alternator to see if it is producing any power. (I'm no electrician but I'm assuming that the low reading I'm getting at the alternator is actually the battery output.)

Do the fuses have any role in the charging circuit-I'm thinking of the main 100 amp fuse which I haven't tested as I gather it's a bit of a fiddle to remove.

This "field voltage"-the next step is to identify the wire (the one normally labelled "F" according to the fact sheet.) and test for 12 volts. I can't see any "F"-can someone describe which is the relevant wire please?

Can't really help very much Tony but I hope a suitable 'techie' may be along before long. A couple of thoughts though.

1) I'd have expected that whether I'd attached my multimeter to the alternator terminals or the battery terminals, I'd see a jump from the resting (engine off) voltage to a voltage around 14v once the alternator kicks in. Certainly, the voltmeter that I have permanently monitoring charge delivery to my leisure battery shows a step up (typically 12.9v -> 13.8v but it varies) after engine start and once the voltage sensing relay has switched supply in.

2) There's been some discussion (can't remember the 'meat') about 100amp fuses in the past. Have you Searched? I do vaguely remember someone blowing their 100amp fuse when replacing - I think - their starter motor because they hadn't isolated the +ve feed and it accidentally 'grounded'. That would suggest that engine starter motor would be duff if the fuse had blown?

3) I presume the red light (bulb) is working when ignition key turned on but engine not started. Obvious, but gotta ask!

4) Any possibility of a duff battery? Obvious again (and unlikely) but gotta ask!

Funny really. If this were any other car, it would be a normal breakdown situation and a trip to the garage. But with this forum 'on tap' maybe that can be avoided.

Good luck!

Mike

[jaylee]

Sorry to hear about your plight Skyhigh.
Grahame's went on the Poland trip, from what i remember his sediment light came on warning that something was up!
The fault was traced to the alternator after Bob, Simon & Keith crawled over it with multi meters!
But the fault was started by a dodgy split charge relay on the leisure battery that had been disconnected a couple of days before..
From what i've learned from Grahame's experience the battery should charge at around 14.5 volts, if the alternators healthy.?

We got alot of fine techies on here, more help will come soon!

Good luck.

[skyhigh123]

Thanks for the quick replies.
Yes, the red charge light does come on with the ignition and goes out as soon as the engine starts.
I'm assuming that the problem isn't with the battery as it appears to take, and hold, a charge (from the battery charger)
The only changes I've made involving the electrics have been to fit a leisure battery and a coolant alarm, both several thousand kilometers ago.
Tony

[mikeonb4c]

Somehow or other, it does sound like the alternator is not delivering charge. But the red light thing is baffling.

I doubt it is the battery but out of interest, how do you know it is 'holding charge'. I've had duff (well 'tired') batteries that will take a charge, start engine and remain fine until stressed (e.g. by a cold snap). Not doubting you (with my limited expertise I wouldn't dare!) but best to push this one around the park just in case

I'll watch this thread with interest and good luck (again).

[baldeagle]

Hi skyhigh,were exactly are you?I am at the northern end of SW close to Angouleme.You are more than welcome to phone me on 0033545389908 and will give you any assistance i can.

Close to me here is a main Ford agent, possible ranger alternator?
Also there is a french version of halfrauds called "Feu Verte", if it is alternator they may well have a replacement.They carry a fair few in stock.
As i say if you are not sorted by now ,feel free to ring if you are stuck,good luck, Brian.

[Distilled Waters Run Deep]

If you can wait you could try these people in Plymouth http://www.startermotor-alternator.co.uk/ Telephone: 01752 221230 Orders for delivery (10-3pm)
Or: 01752 221617 Shop (9-5pm)
[email protected] -cheapest alternators for Bongos I've seen -recon 12month guarantee, less than £100 +postage, new only slightly more expensive -& lovely people too. I don't work for them, just passing on a find.

-my symptoms are similar, but I also have a flashing glowplug light (fans working, scavenger for an extra minute after I shut down; new glowplugs; temp gauge is working...)so it may be a bit more complicated...
Cheers, Phil

[welsh winger]

Just a thought here, check the bulb on the red charge light, it may have blown, I had this in the past, Hillman Imp as I recall, because the bulb had blown, the altenator was not getting the 12 volts it needs to excite the coils and there by not give out a charge, I may be well off track but does not take long the check.

Nick
Welsh Winger

[haydn callow]

Yes, the red charge light does come on with the ignition and goes out as soon as the engine starts.
"carn't be a duff bulb"

[Distilled Waters Run Deep]

this may not help in the slightest... check the big plug under the centre gearstick tray (terminology? what?) to the right of the handbrake.

[skyhigh123]

Thanks for the replies and particularly for Brian's offer of help in France (though I'm actually some distance from you, near Auch , in the Gers)

Still 2 unanswered questions and another I've thought of:

1) Is it ok to start the engine and then disconnect the battery. With a working alternator, a disconnected battery and a running engine, would I expect to see a voltage (?14 volts) across the the alternator to earth?

2) Which is the "F" lead on the alternator?

3) I'm beginning to wonder about the state of the battery as Mike suggested. Would a worn out battery lead to these symptoms i.e. a voltage drop when I start the engine.

thanks again,

Tony

[Distilled Waters Run Deep]

Tony,
first on I'm not at all qualified to know -but if this helps, the breakdown man who attended me disconnected the battery with the engine running: the motor stopped & he said "Definitely needs a new alternator".

[missfixit70]

Surely with the battery discoonected the fuel solenoid valve will shut irrespective of the alternators health?

[jaylee]

Sorry to hear about your plight Skyhigh.
Grahame's went on the Poland trip, from what i remember his sediment light came on warning that something was up!
The fault was traced to the alternator after Bob, Simon & Keith crawled over it with multi meters!
But the fault was started by a dodgy split charge relay on the leisure battery that had been disconnected a couple of days before..
From what i've learned from Grahame's experience the battery should charge at around 14.5 volts, if the alternators healthy.?

We got alot of fine techies on here, more help will come soon!

Good luck.

Surely with the battery discoonected the fuel solenoid valve will shut irrespective of the alternators health?

This was mentioned by some one during the incident on the way to Poland while we were brainstorming what to do next, some one mentioned that the ABS system wouldn't work...?

[teenmal]

Tony,
first on I'm not at all qualified to know -but if this helps, the breakdown man who attended me disconnected the battery with the engine running: the motor stopped & he said "Definitely needs a new alternator".

Your break down man was probably correct.As long as you keep the revs up on engine(ignition light out)you can remove the battery.Another way to check is,headlights on and rev engine,you should see the lights getting brighter.

Mal..