86 k1500 voltage drop

meatheadwes

meatheadwes

Well-Known Member
Joined
Nov 8, 2009
Location
kings mountain
i bought a 86 gmc k1500 with a built motor guy told me battery was bad. i put a brand new battery in it and last night my headlights got dim and went out on my way home. i replaced alternator tonight and charged battery made it 2 miles up the road and lost everything again anybody have any insight on my problem? picture of the truck
10806385_10203264439677229_4771107092346152986_n.jpg
 
Two things, while it is running pull the negative off the battery, does it still run? If so you charging system is good, if it dies you have an issue with the charging system. next thing is you may have a lose ground somewhere. When "everything died 2 miles later" was the battery completely dead??
 
Below 13 runnin . but everything tested good. im stumped. and yeah thats me peeping lol. and ill try it and take negative off
 
make sure your battery is grounded to the engine and you have a good chassis ground. I'm having a similar problem with my 78 cj 5. 12 + volts at the battery but go to crank up the jeep and I lose like all voltage (acts like battery is dead). I have a brand new alternator and battery tested good. I'm confused
 
Baker, voltage drop testing makes that diagnosis much easier! A voltage drop test is also in order with the chevy. Voltage drop on the alternator to battery feed cable. Which alternator is on the chevy? Internally or externally regulated?
 
and my battery has a ground runnin to alternator bracket and to the radiator support. and by the way my distributor is swapped to hei if that matters
 
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