Starting/Charging Problems...

[bethfewster]

Recently I've been having problems starting my car, a 1965 Traveller. My first thought was the battery, so I tested it and it was knackered. I've replaced that, and she was fine for a day. The next day I was driving along and my stereo died and wouldnt turn back on, my lights went extremely dim, my indicators and wipers stopped working....she was slowly beginning to die, yet i didn't notice the red ignition light flickering. We pulled up and I turned her off, and as expected, she refused to start again. We got a jump from some lovely people, and she seemed okay again, except a mile or so down the road the same things started to happen, except this time she went even further and the engine started to stutter and proceeded to conk out completely. We got recovery home Since, I attempted to start her and she fired up fine. I have checked the dynamo, and at a fast idle, approximately 1000rpm, she was giving out 0.6 volts...I was assuming this means the dynamo is knackered, the brushes inside or something, but have been told it could be the voltage regulator. Can anyone tell me how to diagnose what the actual problem is? Electrics are not my strong point... Thanks

[bethfewster]

I should possibly also add that the battery voltage was tested when we broke down and while running it was reading 12 volts. Is it not meant to read slightly higher when running as it's supposed to be charging?

[MarkyB]

Do the brushes first, regulators are pretty reliable.
Think of them as mechanical!

[autolycus]

Google for Lucas XIA116, and download a Lucas Fault Diagnosis Service Manual from one of the many sites it's found on.

Extremely useful publication, but it's no use anyone glancing at it, saying "Too difficult" and asking for it to be written out any simpler here. I've just used it to run through checking a Lucas RA5 dynamo and RF95 regulator, and it also covers most other car electrics up to early electronic ignition.

Kevin

[IslipMinor]

Kevin,

Thanks for the link to the Lucas Diagnosis Manual - a very useful reference document and very good to be reminded of the basic fault finding techniques - saves much guessing and time wasting! Especially the early section on starter motors and permissible volt drops in the circuit.

Looking quickly through it, I found the section towards the end on lights and a description of the 'Lucas Beam Tester MkIII'. We used to make them for Lucas by the 100's at the end of the 70's and early 80's, after they became a mandatory part of the MOT test - very nice business it was!! A real trip down memory lane.

[bmcecosse]

Very FIRST check - is the fan belt tight?? Does the RED IGN light come on when you first switch on the IGN ?? Are the the two wires connected at the rear of the dynamo? You should see 13.5/14 volts when running at decent revs - and that should be maintained with the headlights and heater motor running....

[bethfewster]

Yes, the fan beltis tight, yes, the red ignition light does come on when ignition is turned on, and yes the wires are on properly ...i'm going to double check the voltage again before taking the dynamo off i think

[bmcecosse]

And the red light goes off when you start the engine and rev up? How about the ORANGE light - is it working as it should?

[autolycus]

i'm going to double check the voltage again before taking the dynamo off i think

Why not follow the sequence in the Lucas Service Manual, and let us know the result of each step? Taking the dynamo off immediately means you need a test bench to spin it before you can carry on checking it, and makes it nigh-on impossible to check the regulator at home.

The Lucas method gets you as far as possible without dismantling. You can safely ignore their specification of moving coil meters for voltage and current, and use a DMM. Many cheap DMMs read to 10A DC, which, with care, should be enough.

I must try using a DMM set to "Duty Cycle" on the F output of a regulator sometime - could be an even easier way of checking it.

Kevin

[liammonty]

Hi,
I'm also not great with electrics (so perhaps I shouldn't be advising you!), BUT- if you check the output at the DYNAMO and BEFORE the control box / regulator, this will enable you to figure out which item is at fault (as the dynamo is 'before' the control box). Be careful to set your multimeter to a highish setting when you're checking the dynamo though, as it can put out well over 50 v when the engine's revving a bit (that is, if it's working). You can use the output terminal on the dynamo, and the battery terminal as a good earth. Output here suggests the fault lies with the control box, but obviously, if there's nothing coming out of the dynamo, then it is at fault. Once you've established if it's the dynamo or the control box at fault, you can start tracing the fault more carefully using the handy literature that the others have pointed you in the direction of, or, if you're not very clever, like me, you could just change the faulty component . Good luck!

[bmcecosse]

Easy test for dynamo. Pop the fan belt off - disconnect the two wires. Connect a length of cable to BOTH the connectors - and touch the other end to the non earth terminal of the battery. If the dynamo is good - it will run as a motor. If it doesn't run = knackered dynamo. Probably just needs a set of brushes - very easy/inexpensive job.

[autolycus]

Please don't follow liammonty's advice. Lucas specifically warn against deliberately forcing the dynamo to generate so high a voltage, because you risk damaging it.

Even if you don't damage it by following this unfortunate advice, you'll reach the wrong conclusion. Read that Lucas manual to find out what should happen if you do an open-circuit test as he suggests, and what to do next.

Most car electrics need no more knowledge of electricity than the average 7 year-old is taught: and the Prince of Darkness has spelled out the rest very clearly for us.

JFDI: it's easier than thinking of excuses not to.

Kevin

[bmcecosse]

Does anyone have a FREE download link for that Lucas Manual ??

[liammonty]

Hi Kevin. I'm missing something here- if you could explain to me how simply measuring the output of the dynamo, while it is still on the car and connected as normal is 'forcing it' to give a high output, I'd be really grateful.Unfortunately, my understanding is less than that of an average 7 year old, so I could do with the help.I never realised that measuring voltage with a voltmeter could destroy a dynamo! I always believed the purpose of the regulator was to 'regualte' the voltage supplied by the dynamo, necessary in part due to the fact that at higher revs the dynamo has greater output. It's gratifying to know that you at least have a knowledge greater than that of the average 7 year-old. Lucky us!

[autolycus]

Free download of the Lucas manual here

I thought it would be easier to read the Lucas official version than for me to try to paraphrase it, but here goes:

Liammonty has conflated two separate tests. If you remove both connections from the dynamo, then measure the voltage at the big (D) terminal, the Lucas book tells you that you should get 1.5 to 3v at 1500 rpm. You'll get a much higher voltage if you connect D and F together and then rev the engine too high. It's the high voltage that can cause damage, not the act of measuring it. The regulator does two jobs: it stops the battery feeding current back through the dynamo when the engine's not running; and it causes the dynamo field voltage to flutter rapidly between low and high to maintain the right dynamo output voltage to run the car electrics and charge the battery*. Broadly speaking, and assuming we're talking car electrics not electronics, you won't hurt anything by sticking a voltmeter, or a multimeter on a voltage setting, across it.

My point about 7 year-olds was that most car electric problems are about completing circuits consisting of a battery, a switch, and a bulb, which is what they teach at infant school. When it gets a bit more more complicated - dynamos, control boxes, ignition circuits, - good old Joe Lucas rides to the rescue with his technical manuals and training courses.

* Yes, I know I've ignored the more subtle stuff it does.

Kevin

[liammonty]

Hi Kevin,

Many thanks for the clarification and the link to the manual!

Liam.

[bmcecosse]

Thanks for that free download - excellent! And I'm pretty sure the Regulator doesn't do anything more subtle than the fluttering....unless you have the later 3 bobbin one of course......

[autolycus]

I didn't want anyone jumping on me for not describing how the cutout works, or the presence of the two series windings, or L-C suppressors on some models...

Kevin

[bmcecosse]

At the end of the day - it flutters......

[bethfewster]

i can't actually get the manual still... i'm not sure why