Skip to main content ↑ ↓
Topic: car wont hold a charge-wiring all messed up (Read 2766 times) previous topic - next topic

car wont hold a charge-wiring all messed up

my 86 turbo coupe wont hold a charge, i can jup it and drive it but as soon as it dies it wont start agian.  the wires that go to my alternator are spliced in, the are both hooked up to a goldish colored module on my driver side inner fender the colors are red/black and yellow it looks like. Also my batter cables arent stock becuase the red cable is hooked up to the negative side and runs down to a ground on the block. the positive cable is blue and goes to the small black module on the inner fender.  Can someone tell me where these wires are supposed to be going?
84 TC - under contruction
2018 F150 2.7 4x4 STX
98 F-150 XLT - 4.6, auto, 4x4, extended cab

car wont hold a charge-wiring all messed up

Reply #1 –
post pics of this .....

go to electrical tech sticky called the 1987evtm and you have wiring diagrams for your car, the 86 may or may not be different.

you may have to pull the alt and batt as a group and have both tested.

its best to replace these at the same time because im am pretty darn sure not many people know exactly how to jump start a car without causing damage to the alternator.

look at other threads here like yours and you will see replies.

get back to us on this.

car wont hold a charge-wiring all messed up

Reply #2 –
It sounds to me like something is toast. Have the battery charged and tested. Even if the battery test bad you could still have another problem. Take you car to the local parts store they normally do Battery and alternator test for free. Is your alt/bat light on? or whats the reading on your gauge?  Being an 86 that should have the older style external regulated setup. The gold box should be the reg. Then what are your battery cable like nice and clean or brittle looking. Also inspect you alternator wiring harness. That connector in the harness likes to go bad.
84 Turbo coupe 2.3T Modded with 88 upper and lower intake, 88 injectors, E6 manifold, T3-4 AR.60 turbo, 31X12X3 FMIC, Homemade MBC , Greddy knock off BPV.
4 eyes see better than 2! 
Da Bird!

FreeBird

car wont hold a charge-wiring all messed up

Reply #3 –
i had the alternator tested at the parts store and its good, the battery came out my explorer and worked completely fine.  the alternator cables are spliced and the battery cables look good.  i guess ill get the battery checked for sure.  the guage in the car reads normal when the car is running and there arent any lights on.  i wonder if its the harness that went bad because everything else seems to check out ok.
84 TC - under contruction
2018 F150 2.7 4x4 STX
98 F-150 XLT - 4.6, auto, 4x4, extended cab

car wont hold a charge-wiring all messed up

Reply #4 –
Charge the battery full with it disconnected.  Then hook up the positive cable and measure the current between the negative cable and the negative battery post.  Then start pulling fuses till the current goes to zero.

car wont hold a charge-wiring all messed up

Reply #5 –
There is still that chance that the alternator is bad. Just cause it tested good doesn't mean that something inside isn't toast and suck the life outta your battery. So charge it up and do as told use a meter and start pulling fuses until it drops to zero. You might also want to first disconnecting the main plug from the alt. Just to see if that is the draw. I've seen it before where the alt sucks the batt dry while the car is of yet is still test good in the car and on the bench.
84 Turbo coupe 2.3T Modded with 88 upper and lower intake, 88 injectors, E6 manifold, T3-4 AR.60 turbo, 31X12X3 FMIC, Homemade MBC , Greddy knock off BPV.
4 eyes see better than 2! 
Da Bird!

FreeBird

car wont hold a charge-wiring all messed up

Reply #6 –
Quote from: ipsd;241134
You might also want to first disconnecting the main plug from the alt. Just to see if that is the draw. I've seen it before where the alt sucks the batt dry while the car is of yet is still test good in the car and on the bench.


This is exactly what happened to me.  The alternator was drawing three amps with the key off.  Definitely unplug it first.

Good call.

car wont hold a charge-wiring all messed up

Reply #7 –
it charges enough to keep the car running (well not anymore, now it wont stay running at all) but when i turn it off it is completely dead.  Im scratching my head, i may just go pick up a complete harness for it.
84 TC - under contruction
2018 F150 2.7 4x4 STX
98 F-150 XLT - 4.6, auto, 4x4, extended cab

car wont hold a charge-wiring all messed up

Reply #8 –
Quote from: croga001;241637
it charges enough to keep the car running (well not anymore, now it wont stay running at all) but when i turn it off it is completely dead.  Im scratching my head, i may just go pick up a complete harness for it.


wow,,thats a little agressive to say the least.
we are here to help ,, you just gotta post some readings ect.

Just so you know,, those splices you see are likely the factory fuse links.  yes they are splices but calibrated splices to act as a fuse , ie-smaller wire which will burn open in an over current situation.

car wont hold a charge-wiring all messed up

Reply #9 –
Which alternator do you have?

1


2

car wont hold a charge-wiring all messed up

Reply #10 –
Dude, don't panic and start swapping parts.

Try this.  Drive it around to get it charged and then park it.  If you have 2G as seen above, Unplug the black connector on top.  If it is not dead when you come back hours later, change your alternator.
 

car wont hold a charge-wiring all messed up

Reply #11 –
Its common for the top harness on the 2Gs to go bad inside the plastic mold. But all that harness does is complete a circuit which turns your batt light on and off. It happened on my 5.0 I bought a new harness from Advance Auto Parts and it fixed the light, my Bronco is starting to do it to.  While the light is on I can wiggle the harness to shut it off but never did it cause a drain or not charge the battery.  I would do like the guys said and measure amps while you pull fuses, that should narrow it down pretty good.

car wont hold a charge-wiring all messed up

Reply #12 –
Quote from: Xtremitie;241918
. But all that harness does is complete a circuit which turns your batt light on and off. .


thats good to know,, ill get rid of that stupid voltage regulator now.

car wont hold a charge-wiring all messed up

Reply #13 –
i have the g1 alternator on my car, i parked it for the winter and its time to get it out agian soon i realy want this thing to get running and stay charged.
84 TC - under contruction
2018 F150 2.7 4x4 STX
98 F-150 XLT - 4.6, auto, 4x4, extended cab

car wont hold a charge-wiring all messed up

Reply #14 –
Have you gotten the battery tested yet?

If the car stays running but then wont start, the alternator is most likely charging. The problem is most likely either your battery, or a connection to the battery.