dito! check all your grounds and where is your pump grounded to as well? if its just on the bed run a longer wire to the frame and clean a spot for it to make good connection.
or maybe you just have a crappy alternator i know alot of HP alts if cheaper they need a overdrive pulley to make them spin faster. ive had several cheap highpower alts and all have needed a overdrive pulley for them. and it does help huge! smallest one ive found is a billet piece i got off ebay from a guy that mainly sold steel ones. the steel ones arent as small i actually got 2 of them from him because he kept shipping me the wrong one.lol
only issue ive had with the billet one, which im not sure if really a problem with it or just my belt. after about a year it started to slip and squeal, not sure if it was cause the pulley is billet and its just to smooth OR if the belt was just getting old and needing replaced. all i know for sure is it got on my nerves like crazy so i just slapped the other steel overdrive pulley on it with a stock 145a belt. and for the super small overdrive pulley it used the 105a belt.
ive been meaning to get some sand paper and sand all the groves on my billet pulley and slap it back on with anew belt but it always seems to slip my mind. heres my two overdrive pulleys, and the steel one isnt much smaller than stock but it does help alittle over stock pulley.
You must be registered for see images attach
You must be registered for see images attach
here is a picture of the regular overdrive pulley and its just barely smaller than the one i had on my 200amp alt but then again im not sure if my local alt place used a smaller than stock pulley or not on theres. so maybe my alt already has a smaller pulley. not sure!
You must be registered for see images attach
You must be registered for see images attach
gotta love billet tho. it just looks better
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
overdrive pulley can really help your charge output if you have a weak idle output. i call it my little cheater
its been quite a while since i bought this thing tho so id have to dig thru emails to find who i bought it from and if they even still sell them on ebay.