voltage gauge jumps. lights flicker new alt

[FordCustom]

i have a 91 ranger 4.0 here is the story..

the center of my alt pulley broke out... pushing my alt fan into alt case and taking out the front bearing..... to get buy for a day i spaced out the fan and use washers to hold the pulley on...

30 miles later voltage guage starts jumping and lights flickering when driving slow...gets worst...

picked up new alt. and pulley from napa... installed... guage still jumps and light flicker... will evan if motor is ran at same speed for long periods of time... but if any change in load occurs the flicker starts...

i checked and cleaned battery terminals...
thought voltage reg not reacting fast enough to change... but it had same problem with the old alt aswell...

so i beleive i may have a ground issue... agree?

also i left my lights on for an hour to draw the battery down some to see how it reacted to heavy load... the alt. guage did not jump after start up... when engine was reved slightly lights did get bright which tells me alt. is working...

however i am thinking once battery is topped off the lights will continue to flicker...

any thing else i need to check?

what is weird is that there was no problem with my charging system prior to the alt. pulley breaking... and with the new alt my guage rides on letter higher (still within norm) and my lights are brighter...

again rpm change and load change causes the flicker..

 

[Scrambler82]

Test out the alternator under load and if possible replace the regulator or at least get it checked out. Varying voltage usually means regulator to me.

Double check the grounds on the solenoid and engine to frame; clean and add some anti ox paste.

 

[calypso93]

My 93 4L does the same thing. Every four months I take the two alternator connectors off, and clean the terminals. Nothing seems to last. CRC-DeOxit-Boeshield. Just part of the maintainance routine on mine.