Mopar Muscle Association UK

When you had the car running you should have measured the voltage over the battery at idle and also at 2000-3000 rpm to make sure the voltage was correct and staying correct at speed.

I would hold off on the alternator and voltage reg to start off with

there’s only 2 main things that can go wrong with an alternator; it fails to produce any voltage or the bearings go, in itself wouldn’t stop the car running

can the voltage reg stop the car from running?? wouldn’t have thought so, it would just fail to do it’s job and you would get over voltage

I would disconnect the charging circuit from the alternator, charge the battery, replace orange box and get the car running first

you can then connect the alternator and start measuring the voltage as Dave suggests, you should be ok at tick over as these old alternators won’t produce much more than 12v at that speed anyways

increase rpm and see what happens to the voltage, I’ve not got a manual to hand but I think max regulated voltage when cold is 15.3v(??), this should drop slightly as things warm up

if you’re getting voltage the alternator is fine, if not replace alternator

if the voltage gets too high, shut it off and consider replacing voltage reg and go from there

my advice is only do/replace one thing at a time otherwise you can get in a right pickle

just my

I don't think those ignition modules like any more than 14.5 volts. Neither do standard type lead/acid batteries.

Drop em off to me Morgan,, I'll stick em on the Chally ........and I stilll got a spare elec dist in the office so you can rule out pick up coil failure
Ade

I kept have problems with old style voltage reg so up graded to newer style reg and have no voltage problems since. I have also fitted a volt meter to keep an eye on things.

Ade has kindly offered to plug my ecus into his chally to test which are dead and which are not...

To all those doubters and miserablists out there - this is the reason this club is great.
complete stranger 1 - "Help my obscure vintage car is knackered !"
Kindly sole 1 - "Have you tried x,y,z ?"
Kindly sole 2 - "hmmm. Bring bits up to my place, we'll test them"

You see ? That just rocks.

Will keep you all posted as to progress. Currently liking the 'go to a 12v and a non-mopar ecu' route... Will keep thread updated.

PS you can have a functioning car with battery chargeing and all looking ok with a diode failure in either alternator or regulator depending on where the rectification is done

depends on the style of bridge used for rectification and which diode.

in theory its all working at less than 1/2 capacity but it still provides enough of a DC offset to power stuff

you would only notice if you had a radio and it was switched on.

it would sound like a motor boat.

due to the lumpy half arsed DC you would be running the car on
instead of a flat 12 volt
you would get a semi AC wave form that was like nnnnnnnnnnnnnnnnbusting up to 12 volts at the top of the n but not straying below 0v
rather than nununununununun with a line through mid way up

Dave

Catch 22. Car not running. Cant test alternator.
I think for peace of mind I'm gonna get one anyway. Eliminate something...

Question is what rating ? There are 50A, 120A, 200A. Time for some

too big is not a problem

too small is

the alternator just puts out what is asked for current wise, to keep all things going and a charge into the battery.

i'd suggest if you ever might run electric fans you'd want 75Amps at least

they can pull 40 or 50 at start up which reduces down as their electric motors spin up to operating speed. if your altenator isn't up to it your stereo goes off when the fans start

Dave

I know shipping is crazy from the states but this is what I use

http://www.tuffstuffperformance.com/ind ... cat175.htm

i bought a tuff stuff 100amp one had to strip and rebuild it out the box

Now works fine

Well - here's the latest.

Fitted new Alternator and voltage reg over the weekend got everything wired in again.

Nothing. Nada. Zip. Zilch. Dead as the proverbial.
I’m a bit sleep deprived at the moment so on a very short fuse – I tell ya I came close to writing that ebay ad right there and then. The sheer frustration of a perfectly functioning car being parked in the garage and 3 days later being a dead lump of metal is just maddening. 1wk before MOT and 10 days before favourite show of the year.

Calmer this morning.
New plan is to spend this week very calmly and methodically tracing the entire ignition system (both sides of bulkhead) to ensure that I have connectivity and that all connections are as they should be. That should at the very least give me a pile of components (dizzy , ecu, ballast, reg etc) that are suspect. Might be the perfect time to do the ammeter bypass too...

Sigh. Will keep thread updated. I mean there are only so many things it can be right ?

Use a volt meter. Make sure the coil is getting 12 volts during cranking and in the "run" position. You can get bad connections in the wiring out of the steering column and off the back of the ignition switch. In fact the ignition switches often go faulty after 30-40 years.

Morgan .Check that the coil isn't wired reversed polarity.