LIttle Electrical problem help???

[71Longbed]

Hello all i currently am trying to get my 71 to run right and be my daily driver but i am having a tiny electrical problem wich i think is either the starter or some thing i dont know about alternator has been tested and is running right while i was driving her the other day it shook a little as in a hint of wanting to turn of then it did after that i was only able to switch it on and make my turn when it shut off again it seemed that the battery was dead but it wasnt truck wasnt taking in any power the battery was fine it wouldnt crank for crap now ive also noticed that my headlights and cab lights are very low untill i throttle it ive installed a powermaster starter and had to insert a diode to make up for the R terminal could it be the starter that is defective or is it that the alternator cant supply enough power back to the battery? some one help please!!!!

[Brainchild]

DO you have a ground strap from the cab to the engine,sounds like it needs a better ground.
Also there is a block on the fender beside the battery that runs to the pos side of the battery.That is the power to the inside of the truck,make sure it is making good contact.

[71Longbed]

thanx thats wut my dad thinks it is too im gonna try grounding the engine ive got the little box connected also the one on the fender will try it and let you know wut happens

[71Longbed]

where does the ground cable go on the cab and i can place it any where on the engine right?

[68C15]

you had to install a diode to feed the ignition?! ditch the points & get an HEI. easy swap & nothing could be a better improvement. there isway too much stuff to go wrong with the point style dizzy for the avreage rodder.
what I did is run the neg cable from the front of cyl. head to batt. & run a 12 G wire from batt _ to rad. support making sure to sand paint from all conection areas. as a extra measure you can runa strap from firewall to the top rear valve cover bolt on pass side of engine or one of the bolt holes on rear of that same head would be even better. once again make sure all paint is removed first.

[71Longbed]

yah i had to run a diode or else it would only start while i had the key down if i let go it would shut off so i had to run a diode to keep it turned on i tryied runing a mallory electronic but for some reason it would want to get timed up right my points are perfect she idles like a new car its cuz my dads a points pro but i am looking ot swap it out to an hei i do have it already!

[68w/sbc406]

as far as grounding i put a ground strap back in one of the bellhousing bolts and to the wholes on the frame where the manual crossmember goes. and another one from the same location to the big innerfender bolt. they are far enough back that you cant see them unless you are looking for them

[71Longbed]

Looks Like the securing on the little box and an additiopnal ground strap from engine to chassy took care of the light dimming problem hope it doesn't continue to shut off need to drvie thisthing everyday

[68C15]

from personall experience Mallorys are a bad thing. they have absolutely no tolerance for questionable grounds.
as far as the diode thing, the way the points system works is while cranking the starter R terminal supplies a full 12 V to coild for a hotter spark & then when key is let off to the run position the resistor wire coming from bulkhead on firewall supplies about 7 volts so the points last longer.
does your new starter have the R terminal?
with key in RUN & engine off do you have voltage at + side of coil & how much?
it almost sounds like a problem with the resistor wire, connections at bulkhead, or ignition switch.
check these & let us know.

[Longhorn Man]

Originally Posted by 71Longbed

...installed a powermaster starter and had to insert a diode to make up for the R terminal...

If I'm reading this correctly, he has it wired up so that the yellow wire is hooked to the purple wire on the S terminal becouse the new starter doesn't have the R terminal. This would have the exact same outcome as if it had an R terminal and was wired up as stock.

However, there is no need for a diode, and it hinders easy starts. As stated before, the yellow wire is supposed to supply a full 12 volts to the points for a short burst of real big/hot spark to help starting. If it needed the reduced voltage, then the yellow wire would not be needed at all since the stock cloth covered resistor wire is powered durring engine cranking.

[71Longbed]

The Diode has to be there to keep the truck on tried to do it with out it wouldn't stay on dide is place on the orange wire wich was spliced in with another on the starter wich i dont know if its red or brown can tell too faded

[Longhorn Man]

After re-thinking it, it IS needed, to prevent the reduced voltage from the coil from back feeding down the yellow wire and to the S terminal and trying to engage the starter while the engine is running.