4G alt weirdness?? opinions??

[blazinchuck]

alright guys,just swapped in the cam'd up 306 in my 77. im using a junkyard explorer serpentine system(reusing the alt that cam with it)

everything has been doing good so far, started driving monday...no problems til today. got off work, headed to pick my daughter up from school(no problems yet)

got back in, cracked it up and started driving...couple blocks down road and noticed engine light was on. started looking around for clues and noticed the volt gauge reading below 12. when i put a blinker on the pull off road...looked like it was flickering and dropping close to 10v. so i shut it off, popped the hood to see if i lost the belt, a wire or anything....(NOTHING)


cranked it back up and no engine light, volts reading 14...so i went to O'Rileys to have the alt checked. he told it was good, charging @14.1, diodes were good and was putting 64 amps out...


im kinda stumped...can the volt reg maybe drop in and out?? maybe slowly going bad? I thought the 4G alt was 130 amps? maybe not at idle... just dont want this alt to bite me in the A when i least expect it

[bucketobolts]

Could be a connection problem, either the green/red wire turns it on and the yellow or yellow with white wire senses how much voltage needs to be produced.

[blazinchuck]

well, as for the ground...those are good, i have extra grounds also.

just cranked it up again(brothing in law came by to see new motor) just as it started...the light came back on, looked at the volt gauge and it was just below 12v again. so i shut it down, and recranked it...and no light and showing 14v again.


im thinking the regulator is going bad....dayum

[chuzie]

dont worry about the light. it is likely the eec telling you the vref is too low which is a result of the alternator. i would put my bet on the volt reg but check out your wiring too.

[blazinchuck]

ok, i guess i was wrong...sorta.

after wondering how it can work right/then not work...i figured id better atleast check my wires again. i was using the flat spade connectors...since i 1st had a 2G alt with the mustang serp, then upgraded to 3g...i figured it would be easiest for swapping alts.

looks like the one i just crimped onto the alt ign wire was a hit or miss getting power from rjm. so i use a high quality but connector and it seems to be working right everytime so far.

[BucknEB]

Fixed it.:xyxthumbs:

Fun test drive just to make sure everything was working/ charging correctly.upergrin:

That's 2-0 for Bronco fixes at the house tonight.:xyxthumbs:

[SC74]

Glad it turned out to be something simple (and cheap)!