[moparPW200guy]

hey everyone... i hope you all have seen my 77 PW and like it but i have a problem....... at idle, in gear, with the lights on the amp guage is pegged at D and the lights are hella dim..... plus if i turn anything else on it dies..... i have replaced EVERYTHING exept the amp guage.... i have a new one but it doesn't match the rest of them.... if i bring the idle up to 1000 RPM it levels out dead center... my radio wont even work at idle.. let alone anything else.. i have replaced the alt with the A\C unit and it didn't help at all.... new regulator, repaired the wireing in the charging circuit that was bad, and it still had no effect.... if anyone else has had this problem PLEASE HELP!!!!!! i dont feel like having to give up on this beautiful truck but if i cant get this going i will be forced to trade it for a newer truck...... and i dont want that. a 77 PW was the first truck i ever drove and i've finally got one of my own and i dont want to give it up... please help if anyone can..

thanx
mark

and the belt tension is fine....

 

[Chump]

Is your new regulator getting a good ground...it grounds through its case to the firewall. Did you replace the alternator with a rebuilt one? What voltage do you have at the battery with the truck idling with NO accessories turned on?

 

[77ramcharger]

When you say you repaired the wiring, just how much did you repair? Did you follow the wires all the way from end to end, or only what you could see? Be sure to check the bulkhead connector as it is usually the first to go, and also i have seen the wires inside the harness melt going across the back of the engine from the bulkhead to the alternator.

 

[moparPW200guy]

there was one wire that was broken at the regulator but that was the only one i found... i'll check the bulkhead connector today and check the rest of the wireing while i am under there.... as for the alt and regulator yes the alt is rebuilt but it pushes 86 amps under load... i dont know about at idle.. and the regulator is grounded properly.. i went down to bare metal on the firewall when i replaced it so it would have a good ground.

 

[webbcraft2150]

70 series Mopars, cars and trucks both, are nortorious for this problem. The alternators just dont put out enough at idle, period. One thing you did not mention was the condition of your battery. Get it load tested. Put a voltmeter on your battery while engine is running, should be 13+DC with the engine running @ 2k. Since you can sit around idleing @2k here is how I fixed the problem on my 75PW and 70RR. I went with a "one wire" delco alternator. You can find these at Summit or Jegs if your rebuild shop does not have one. I had to get a longer belt and shim my brackets out with some washers. This unit has been install for over 10 years now with no problems. Rated output is 101amps, and is a "standard" sized alternator. I get 14.2v @ 900 rpm. They are internally regulated and need only "one wire" run from the alternator to the + side of the battery. I left my OEM regulator in place to keep the "stock look".

 

[Chump]

there was one wire that was broken at the regulator but that was the only one i found... i'll check the bulkhead connector today and check the rest of the wireing while i am under there.... as for the alt and regulator yes the alt is rebuilt but it pushes 86 amps under load... i dont know about at idle.. and the regulator is grounded properly.. i went down to bare metal on the firewall when i replaced it so it would have a good ground.

86 amps? Was this alternator custom rebuilt or did it get one of those upgrades that places like JC Whitney sell? The upgrade kits will NOT produce much of anything at idle, I know, I had one. They will work fine once the engine RPM is increased. A standard alternator with A/C back in those days was a 65 amp. Optional was 114 amp. I also have a 77PW since it rolled off the assembly line. I finally changed mine to a Powermaster about 2 weeks ago and it looks and works great.

http://www.powermastermotorsports.com/mopar_early_style.html

 

[jto]

I had a stupid little wire that was eaten away from the inside out. The insulation looked good but the wire was shot due to a leaky battery. It lead from the battery to a ground on the radiator mount. Yes, I changed my Alt, VR, and wires EXCEPT for that STUPID LITTLE WIRE. Now it works fine.

 

[macario]

moparPW200guy:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Check this out regarding your amp gauge.

 

[Guest]

No offense, PW, but you don't have the alt wires crossed do you? The red wire is the field.

 

[slantsixness]

Do you have the fields reversed on the alternator (the two wires other than the red (+terminal post)one)?
You could have burnt a fuse link too. Don't be suprised if the revesed fields blew out the new regulator.
Do you have 12V battery to the top regulator terminal (as it's mounted, with the socket at the bottom...) with the vehicle ignition on?
Alternator Problems are not very hard to solve. And there are 65,85,115 and 125 Amp versions. there's even a 55Amp version for early '70s A-bodies...

 

[moparPW200guy]

the alt is a parts house rebuild.... i had it tested at napa and it was showin 86 amps under load.... the feilds on the alt are not marked, and there are 2 wires for the feild... red AND yellow.... then a big fat black one that i thnk runs to the battery but i dunno....so i'm not sure which way it goes.... i put it back the way it was before i pulled em... i just pulled the dash cluster for the first time and over one of the amp guage posts its marked RED.. is this where the red wire goes i know its a stupid ? but i have never had this may problems with my other mopars so its kinda buggin me..... and i have had those apart MANY MANY TIMES and never noticed that.... i have had the battery load tested about every 2 weeks because i dont trust EXIDE batteries but thats whats in there so i am stuck with it for now till i can afford a good mopar or diehard battery.... i have 13.3v or so at idle and 14.1v under load... right now i cant afford a whole lot to fix this truck but if i have to i can possibly scrape up enough for a volt meter and be done with it...

thanx for the info and i'll keep pluggin away at it..

 

[moparPW200guy]

well i found out my amp guage was toast... it had started to melt the instument housing so i left it in and wired up a new amp guage that i had laying around... it works but still wont charge at idle with lights.... i'll figure it out eventually....

 

[moparPW200guy]

well i think its working finally... tonight i had the headlights, heater fan, radio and wipers on with it in gear and it still dimmed the headlights but not nearly as bad.... as soon as i get the money i am relaying my headlights since i have H4 halogens in place of the stockers now... that should solve my problem.... thanx guys and gals for all your input!

 

[moparPW200guy]

well today i pulled my bulkhead connector apart and may wonders never cease on this truck it was PERFECT!!!! no melted anything.... i guess i fixed it befor it melted the connector... just wanted to update