Does your car show a charge on the gauge at idle,

or does it only show a charge above idle speed ?

 

should show a charge all the time otherwise if you let your car idle it would die after a long time.

 

Thanks craveman, my idle speed is 900 rpm,but its not charging at that speed. So what can i do about it ?

Is there a smaller pulley available for the mopar alternator ?

 

there could be but your alternator could be bad or your voltmeter could be bad. go to a parts store and ask if they can test your alternator

 

I'd put a multimeter on the charging system, that will tell whats what.

 

If your alt. checks ok, some ideas; Old mopar alts have a tendency of going to discharge when idling due to the lower output in general and design limitations of alt. and problems that come about due to age of the system.
Usually the alt pulley is as small as it can get for practical purposes. If you went smaller, you might have a problem throwing belts.
I like using the alt from an '88-'89 diplomat [the one with the narrow seperator plate, 'bout 1/8th inch] they charge better at idle when used with an electronic voltage regulator, [same size as old alt. also]
Most likley problem is voltage resistance in connections and wires themselves. {believe it or not wires can develop resistance inside them}
Gotta check for voltage drop, cheap digital volt/ohmeter will suffice
{voltage lost at connections or through corroded wires}
Prime targets; bulkhead connector and alt./batt connections/wires.
check grounds for excessive resistance.
Actually the amp gauge wasn't one of chryslers better ideas either. Just about all amps/volts has to go through it and thats after it goes through the bulkhead connection first. Lots of connections-lots of opportunity
for bad connections. The amp gauges were only good for about 35-40 amps anyway. Real easy to get to those numbers with a few added accessories. Sorry this was soo long...I get carried away sometimes.

 

actually look for a service diplomat like a taxi or a cop car they had a high output alternator even compared to the regular dippy ones

 

Real true craveman; you could probably use one of those types as a portable welder!!!

 

if you cant charge with that you need some new wires. even a wore out one puts out more juice than most new alternators but they also had to power all the radios, and sirens and lights.

 

Hey I might be joining the ranks of the "M" body clan. Got a hot lead on an '83 gran fury, {might be ex detective car, guy not sure} Real nice shape and runs good for $600. Ill keep ya posted.

 

Check your belt, make sure that it is snug. Inspect all the wiring from your alternator to your battery and to your cluster. After that, have the alternator and battery tested.

 

there are a few ways of checking to see if its an ex detective car. It will have a rear sway bar, 5 leafs in the rear springs, an 8.25 rear end, usually a 727. they also have 360 heads, a thermoquad carb, hypernutic pistons, a power steering cooler and a few other things. Most of them you cant downshift into first gear to protect the tranny. they had a lockout to keep cops from dropping it to 1st and whipping around to catch somebody. also most of the service vehicles had bucket seats and a rubber floor instead of the inch thick carpet like my fifth ave has. im planning on putting one of those in my car to get out the stink. also when i vaccum it i keep pulling up more grass seed in the back seat every week.

 

dippy.org is only for m body cars

 

Ok guys,thanks for all the help!

By the way, I aint gonna find a Diplomat in the UK thats where i live !!

 

hmm that could be a problem.

 

Hey, I found it. The large bolt that fixes the alternator to the motor screws into the cylinder head, and that is the alternators earthing point !

Cleaned it all up and also fitted an extra earth wire from the alt to the motor. Problem solved. Charging is good now.

 

awsome man