ELECTRICAL HELP!

Dec 20, 2007
94
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El Sobrante, CA
I have a 1986.5 NA supra 5 speed. I went to start my car and it wouldn't even crank. That was the first time that ever happened. All the lights and radio and everything came on but the engine wouldn't crank. So I changed the little wire in the fuse box (circuit breaker?) and it still didn't do nothing. So I changed the positive battery cable. It cranked but wouldn't turn over. I rolled it down the hill and popped the clutch and the car started. Once I got down the hill and stopped, I pressed on the gas to go again and everything went dead. No lights, radio, not even the windshield wipers. I tried to start the car and it didn't even click. The headlights come on and the hazard lights. Nothing else. I checked all the fuses and everything and all was good. What could it be? Could it be my ignition? I have an msd 6al ignition box and it has shorted out on me a few times but I could shake it and it would come back on. Could it be that it just went dead or is it something else?
 

osama1234

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Jun 30, 2007
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vancity
I'm no pro here, but..the little wire in the fusebox you changed, was it burned out? (you didn't mention if it had burned, or whether you just change it cuz you had a hunch).
If it did burn out, at least you've got somewhere to start, looking at http://www.cygnusx1.net/supra/Library/TEWD/MK3/manual.aspx?S=Main&P=33, you can see what circuit it is powering, so it gives you somewhere to start to look.

I'm not sure what you mean by 'little wire', but does it say on the fuse box 1.25B where the 'wire' used to be that burned out? if it is, that fusable link is connected to the alternator, so i'd check out the alternator if it has issues.
Interestingly enough on the last linked page they dont show the fact that that fusable link also goes to power the starter circuit http://www.cygnusx1.net/supra/Library/TEWD/MK3/manual.aspx?S=Main&P=038
so it makes sense that that fuse blew because of some electrical issue in the car, and then the starter wouldn't work cuz it uses the same circuit.
This is all ofcourse speculation, i dont even know for sure if that fusable link blew or not.
But yeah, TEWD = best friend.
 

PROJECT N00b

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May 22, 2005
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TJ: Mine has done something similar to this (AT NA 87). I took the car to Autozone and they checked my alternator and battery...both checked out fine. I had the starter changed and the EFI main relay. WTF is going on?

/TJ
 
Dec 20, 2007
94
0
0
El Sobrante, CA
osama1234;918990 said:
I'm no pro here, but..the little wire in the fusebox you changed, was it burned out? (you didn't mention if it had burned, or whether you just change it cuz you had a hunch).
If it did burn out, at least you've got somewhere to start, looking at http://www.cygnusx1.net/supra/Library/TEWD/MK3/manual.aspx?S=Main&P=33, you can see what circuit it is powering, so it gives you somewhere to start to look.

I'm not sure what you mean by 'little wire', but does it say on the fuse box 1.25B where the 'wire' used to be that burned out? if it is, that fusable link is connected to the alternator, so i'd check out the alternator if it has issues.
Interestingly enough on the last linked page they dont show the fact that that fusable link also goes to power the starter circuit http://www.cygnusx1.net/supra/Library/TEWD/MK3/manual.aspx?S=Main&P=038
so it makes sense that that fuse blew because of some electrical issue in the car, and then the starter wouldn't work cuz it uses the same circuit.
This is all ofcourse speculation, i dont even know for sure if that fusable link blew or not.
But yeah, TEWD = best friend.


The had been changed before by the previous owner because he said that it had went out. He just replaced it with a little piece of wire he had laying around. He said the wire was a little thinner than the original wire that was in there. When I looked at it, it was white, so I assumed it was fried. So I went to kragen and bought a fusable link because they didnt have any wire to just replace it. They said the fusable link would be better.
 
Dec 20, 2007
94
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El Sobrante, CA
suprarx7nut;918995 said:
This may seem dumb and basic but have you checked the battery? :dunno:

If the battery is dead and it died even after pop-starting it, you may have a bad alternator.


I charged my battery, thinkin that that might be the problem and it wasn't. The battery is brand new and I charged it. So that aint it
 

cuel

Supramania Contributor
Jan 8, 2007
1,536
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Baytown, Texas
The fusible link is better because that's what is supposed to be there. You could also put a 100 amp main fuse there as well.

The "head lights and fogs came on but nothing else..." sounds familiar. Think this makes the third or so post in the last 2 weeks with similar symptoms.
 
Dec 20, 2007
94
0
0
El Sobrante, CA
cuel;919785 said:
The fusible link is better because that's what is supposed to be there. You could also put a 100 amp main fuse there as well.

The "head lights and fogs came on but nothing else..." sounds familiar. Think this makes the third or so post in the last 2 weeks with similar symptoms.



So then what is it?!
 

cuel

Supramania Contributor
Jan 8, 2007
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0
Baytown, Texas
lol. If I knew, I'd tell you.
I'd start with making sure the battery is charged, connections are clean and tight. You could check behind the driver's kick panel, and make sure all of the connectors there are plugged in, and none are loose. In the wiring diagram, it shows some other fusible links off the ignition circuit, but I don't know where they are located.

http://cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=D&P=3

If you do figure it out, post up the fix, so other's will know.
 
Dec 20, 2007
94
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El Sobrante, CA
cuel;919835 said:
lol. If I knew, I'd tell you.
I'd start with making sure the battery is charged, connections are clean and tight. You could check behind the driver's kick panel, and make sure all of the connectors there are plugged in, and none are loose. In the wiring diagram, it shows some other fusible links off the ignition circuit, but I don't know where they are located.

http://cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=D&P=3

If you do figure it out, post up the fix, so other's will know.


Asking me to figure out electrical issues is like putting a 2 year old in trigonometry math. It aint happnen! lol. I was hoping it was something simple. I checked all fuses and cables coming from the battery. Could it be my ignition?
 
Dec 20, 2007
94
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0
El Sobrante, CA
cuel;919861 said:
It "could" be. I'm not sure, though. If you can't work on electrical systems, you really need to take it to someone who can. Jetjock could probably do this with ease, but I'm not an electrical expert, and, as such, will only tell you to check the basics.

You might do some reading here: http://www.supramania.com/forums/forumdisplay.php?f=111, and see if there's an answer there.



I've been thinking it could be because i have an msd 6al ignition box, and a few times while i was driving, my car would stall. I could shake the ignition box and it would start back up again. when i popped the clutch rolling down the hill, i dont recall hearing the ignition box. could the car start without the ignition box working?
 

cuel

Supramania Contributor
Jan 8, 2007
1,536
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0
Baytown, Texas
I don't think it would start without the ignition box being on, but I don't know much about them. Shaking it probably isn't doing it any good, though. Sounds like it has a loose connector somewhere, or maybe a broken wire.

The point is, it could be quite a few things.
 

AJ'S 88NA

New Member
Jul 26, 2007
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Florida
MrTwinTurbo1988;919011 said:
I charged my battery, thinkin that that might be the problem and it wasn't. The battery is brand new and I charged it. So that aint it
But what about the alternator? Did you have it checked? Others on here have bought new one and they were still bad. Another thing to check is the belt tension, especially if the battery and alternator check out. I thought my battery was bad untill I had it checked and it ended up being the belt not being tight. Worth a try as it cost nothing. Your battery can have enough power to have the lights working but not enough to start.

Also if I were you I'd get rid of the MSD box does sound like it's not very reliable.
 
Dec 20, 2007
94
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El Sobrante, CA
AJ'S 88NA;920012 said:
But what about the alternator? Did you have it checked? Others on here have bought new one and they were still bad. Another thing to check is the belt tension, especially if the battery and alternator check out. I thought my battery was bad untill I had it checked and it ended up being the belt not being tight. Worth a try as it cost nothing. Your battery can have enough power to have the lights working but not enough to start.

Also if I were you I'd get rid of the MSD box does sound like it's not very reliable.


I think my msd box is just defective. ive heard from alot of people that msd is great so im giving it the benefit of the doubt right now. I will check the belt tension though. Thanks for the tip
 

UpbeatFish

Permanently Banned
Oct 4, 2007
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Fail town
MrTwinTurbo1988;919843 said:
Asking me to figure out electrical issues is like putting a 2 year old in trigonometry math. It aint happnen! lol. I was hoping it was something simple. I checked all fuses and cables coming from the battery. Could it be my ignition?

man that happen to me. it ended up being a batt wire. it wasnt connected right. my dad fixed it on a rainy day. IN THE RAIN lol =]
 
Dec 20, 2007
94
0
0
El Sobrante, CA
UpbeatFish;920189 said:
man that happen to me. it ended up being a batt wire. it wasnt connected right. my dad fixed it on a rainy day. IN THE RAIN lol =]


Well Its not that because the car was working before and then it just wacked out, then after I changed the positive battery cable, it worked again but then went out
 

pres6

New Member
Aug 12, 2007
29
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Richardson, TX
do your self a favor and wire in a new ground wire from the battery neg to body, and from engine block to body.. still nothing?
this just has that grounding issue feel to it..
BTW, if you blew the original fusible link, there was something wrong with the electrical to begin with, if you replaced it with regular wire there is no telling what else it burned up when you were driving it.

if its me tho, i am going the through the entire engine bay and busting loose all the grounds and re-tightening them, other than that, start swapping parts.