RB26

Hey I've got a 1981 280zx and my relay box under the hood is messing up. the battery to accessory short ground wire in the box is blown so i replaced it and when i put the terminals back on it fried instantly. i have traced the wire into the car and there is no damage or breaks or exposed wiring so im not sure of the issue. Most of my guages don't work and none of my tail lights work. Could this be the issue?

duckyz

You replaced the wire or the box?

I had pretty much the same thing happen in my '83, except my relays were all good. I couldn't find anything, so I took it to my mechanic who found a bad splice under the dash.

You're going to need a volt meter and lots of time.

RB26

here is a pic of the relay...it is right next to the battery and attaches to the positive terminal. If anyone can post a pic of there working relay it would really help me to figure out what is wrong with mine.

FricFrac

That's your fuseable link box and it's missing the EFI harness connection....

RB26

i replaced that wire and when i connect the terminal that wire smokes and melts......what could be the issue?

koprutzxt

does the car run fine, auto or stick, does the fuel pump prime when u turn the key to "on"

koprutzxt

that fusible link connects directly to the battery and to the alternator have your alternator and batt tested

RB26

car runs fine and fuel pump is working great from what i can tell. its a 5 speed manual...alternator and battery are good.

koprutzxt

ok just some added knnowledge that fusible link wire is used to manage the the current of amps flowing to the battery from the alternator if there is to many amps passing through it it will become hot andfry to save your battery.it does not go into the car at all just from the alt into the box and to the batt.. is your alt. under warrenty??

koprutzxt

also how is ur negitive cable has it been replaced before??

RB26

only had the car for about 2 months now...its an 81 so no warranty. the box runs into the car by the wiring harness under the dashboard on the glovebox side.

FricFrac

"your EFI connector is missing"

I would say there was something wrong with something on the EFI circuit. Start off by disconnecting everything hooked up to the EFI circuit and see if it blows the fuse then start hooking everything up one at a time until it blows the fuse or use a multi meter...

ZZzzz

no kidding... this is EXACTLY what happened when i put the battery in backwards... check that.

RB26

my box is connected to the positive terminal...and im not great at wiring. if anyone has some pics to help me check it out then it would be greatly appreciated.

koprutzxt

well dude that wire thats blowing out origanally comes from the alternator where it says batt.. in the fusible link box you'll find 2 copper plates. one plate that connects the 4 ajescent links(going to systems) to one black wire that leads to the batt.. and the other two ajacent ones (to system)to another plate that connects to the other black wire that goes to the batt. so if that one wire is frying out and not the other 3 connected to that plate, rest easy. you batt is fine and the cars systems have no shorts and are grounded. but since the one wire that connects to the plate and the alternator keeps frying out then it must be a bad ground on the alt or bad regulator. its fizziling out to protect the other fusible links connected to that plate. have you had the alt tested while its on the car im sure it will come up.

RB26

if the alternator is bad wouldn't i notice a power drain eventually? or if its just the ground then what am I looking for when i get it tested? ill be going tomorrow to get it checked just need to know what kinda issues im looking for.

koprutzxt

they should use a tester with an led display or some kind of digital read out analog ones will not be sufficient oriellys uses a good one when i go. it will tell you how many amps your puting out a good z should have 60 amps however my n/a 5 speed zx only reads 45 amps but has never failed to charge the batt or run my systems with subs so one of those quarks i guess. the voltage should be between 13 and 14. at oriellys the machine will also tell you if the diode and regulator are good.. hey and just a side note in my early days of learning these zx's i was messing with the wires near the ignition coil and had plugged two of them together that same fusible links started to smoke and fry itself.. if the alternator checks out good. head to the junk yard and hopefully you can pocket a whole bunch of links from any z as long as they are the same thickness. unplugg wires that may not belong together i.e.. wires that do not have a specific mating connectors, have butt connection, audio speaker lookiing connections, or spliced wires.
1)be sure to unplug the negitive cable from batt,
2)put the fuse link in,
3)unplugg suspect wires
4)put neg cable on see if the wire frizzles
5)if not then start to put wires back together one by one following steps 1,2,and 4 always unplug neg before connecting wires because the wires you are connecting can become hot and burn you
it will be pain staking amigo but thats diagnosing for ya please let me know what you find we'll figure it out together. feel free to post pics and ill compare what i find on my ride, if your unsure the way something is connected

FricFrac

OK so.... apparently I'm retarded... I was looking at the fuseable link upside down. It's the ACC that is missing so it doesn't have anything to do with the EFI. Take all the B1, B2, ACC2 and IGN fuses out of the fuse panel and see if the fuseable link blows (I'd use either an inline fuse or multi meter to test).

koprutzxt

wow fric frac.. i like this scematic one of my z's has been tormenting me with an electrical issue i will be using this for a possible test is this from the hayens manual ?? i have not used it in so long..

RB26

you guys are freaking awesome...after work tomorrow ill be running through the wires to figure this out. i really appreciate all the feedback and advice. ill keep everyone up to date and post pics during the process.

RB26

i spoke with o'reillys and they said they cant test the ground on the alternator...how do i test to see if the ground is good? Also, do i need to remove my alternator to get it tested or can they test it in the car?

koprutzxt

while its in the car .. they will hook a tester to the terminals then ask you to start your car. it will the test for amps, voltage, if the diodes good, and if the regulator is good. a bad ground can be noted if the voltage is low and everything else checks out. i always test the grounds by romoving my electric fan ground and seeing if the spots of another ground is good. maybe if you have some other kind of aftermarket guage you can try this. make sure the black wire is hooked up to the E-earth on the alternator. and check to see if theres a black wire bolted to a screw on the engine block near the oil pressure and just behind the alt

RB26

there is a black wire bolted to the back of my alternator along with a thick white wire and a short white wire. the short white wire is broken though but with no connecting end that i can find. Heres a pic of what im talking about. I know the pic is dark but the large white wire you see is bolted to the same connection as a large black wire (too dark to see the black wire underneath) and then the thin white wire that im pointing at is the broken one.

RB26

just had the alternator tested and heres what I got for results:
Diodes - Good
Regulator - Bad
Amps - 30
Volts - 12.6

Now should I replace my ground or the alternator?

koprutzxt

the 280zx alternator has an internal regulator in the alt. so you will need to replace the atlernator. lifetime warrenty at o'riellys.. thats a start and 30 amps is low but can increase with reving at 2500rpm while testing, however with out a good regulator the amps are not going to be in check.
about the broken white wire: The little battery looking thing on the back of the alt. is used to keep static from the alt from effecting your stereo reception.
On new alts. they are mounted on the back and connects to the batt. space on the alt along with the large white wire.
now, that little wire used to have a butt connection that would connect to the battery static thing on the stock alternator only. its cut on mine and in not used in any zx with a new alternator.
so your new alternator will not need that wire. i only explained because i want you to know its a useless wire, so you wont try to hook it up to anything. i know how tempting it is to want to test every possible solution.
the alt is about 80 bucks so if you dont have the cash in hand please PM me when you get a new one so we can continue this thread and i can assist with the best way to get it out because its a pain if your power steering pump is mounted still.i know tricks..