84redta

iTrader: (34)

Literally nothing works except the dome light. I was in the process of wiring in power mirrors, power windows, power locks, and under dash lighting. I zip-tied back the door sensor for the dome light and buzzer to make it stop buzzing, and as I'm laying on my back I go to uninstall the fuse block to wire in some of the electronics when all of a sudden a really big spark when off in my face like a flash grenade and i couldn't see anything. Less than a second later the buzzer doesn't work and i can finally focus my eyes again. I look up and there is a dime just chillin where the spark came from originally. I removed the dime and started digging for wires while laying under there to no availe. Then a second later i believe it sparked, i was just walking back to the car from my tool chest and then it started smoking. I again spend an hour looking for wires on the driver side that would spark/smoke. What wire would kill the ignition to the engine, the dash indicator lights (when ignition gets turned on), the gauges, and the radio? All i have is the dome light, interior lights if i turn on the parking lights, i have exterior parking lights with the switch on, and for headlights i have headlights that come on, but they don't motor up anymore. What did I do!?!?!? Please help! Will a wire sit there grounded out to the point that it melts apart?! Could that be the smoke and the lack of power to anything?! It seems as though it has no ignition power anymore, where approximately does that run? And wouldn't something like that be almost obvious when it blew up in my face?

I've checked all fuses, and relays in the fuse block, and i've canvassed wires for a couple of hours. If this sounds like I burned up an ignition power wire just someone confirm it for me, or if you have any other suggestions please let me know. Thank you very much for you time and help!!!

84redta

iTrader: (34)

Forgot to put anything about the car. It's a 1988 Firebird 5.0L TBI 5 speed manual. As i said, it did work, now it doesn't. Thanks for any help!

Corky

Go down to the starter and check your fusible links. More than likely, that's where the smoke and burn smell came from.
Corky

84redta

iTrader: (34)

The smoke came out the drive side of the dash right around the area of the fuse block/sparking incident. It was coming out the side and out the vent. I physically witnessed that part.

will check fuses elsewhere tho, thanx!

84redta

iTrader: (34)

ok update...

found source of the short, it was a wire that must've been rubbing for quite a while cause it was worn away and the spark definally created the smoke and such, there were little burn marks on the wires around it.The short was some red/pinkish wire coming through the firewall. Tested that at both ends of the burn and got identical readings of 1.095 volts, so i don't think the burned area was affected, just the coating. But obviously whatever shorted something big out is still getting a small amount of voltage...what could do this!?

Anywayz, Corky, you said check the fusable links...where are they? Off of my starter i have a couple of wires, and 3 of them have little black circular tubes on them (Assuming fusable links???), but they don't appear that they could seperate and have a fuse in them (or melted what so ever for that matter), and i've looked for a bit inside the engine compartment from up-top, and found another one near the battery. Is there a way to test which lead it is? How do you replace them, the haynes manual says to cut out old one and put in new one!? How do you tell if they are bad?? And how do i tell what they are rated to get new ones!?

~jon

Corky

I have the '88 service manual. THe fusible link by the battery should feed the alternator. The diagram shows fusible link A, feeds the fuse panel. This fusible link is located on the starter solenoid. You can test fusible links the old fashioned dirty way - use a test light on either side to check for power. Just put a dab of silicone in the place where you pierce the wire insulation. Usually when a fusible link goes bad, the black tubes get all distorted and show signs of melting.
Fusible link B feeds the ignition switch. Check for power on both sides of all fusible links & we'll go from there.
Corky

84redta

iTrader: (34)

Ok, I checked what looks like a distribution block to the right of the battery behind the headlight, checked the fuse to the right of the battery (I don't know if that is universal or aftermarket something), checked the fuses under the dash, switched out the two curcuit breakers out with ones that work, and checked the voltage at the starter, and at the terminal with those three fusable links, i am getting full voltage of what the battery read. Is there a way to identify fusible link A to the fuse panel and would i be getting +/- 1.095 Volts if it was blown?? I checked all the fusable links at the starter...i get 12.35 V at the terminal, and after 2 out of 3 of the fusable links i get 12.35. The third one however my volt meter can't pick up a voltage before the fusable link and after it, it splits internally into two wires and each wire is reading .30 MV or 3.0 MV, i can't remember at this point, but either way it's not reading the 12.35 V like the others.

All the fusable links show no sign of deterioration or burning what so ever. I checked inside the car...behind the fuse block is some sort of distribtuion block of battery power and ignition in the form of a plug?! well on the battery side i get the full battery voltage (+/- .01 V) and on the ignition powered side (side A of the plug i believe, away from the cliped end) and i'm getting that 1.095 Volts again. Why am i getting 1.095 (+/-)?

I took a jumper wire and at that distribution block connected the battery side with the ignition side, and I get full accesories back, i get the buzzer, flip up headlights, all dash indicator lights and guages, and if the battery wasn't low from having the interior light on, i probably could turn over the engine. This is everything that i've checked and done with results, where do you suggest i go from here?

Jon

Corky

Sorry, I was out of town all week. Using the jumper wire was a good troubleshooting trick. You have found the problem, now you have to locate the source. The 1.095v is just stray volts picked up by the DVOM. There is a fusible link that feeds the ignition side. I think you said you could not get a reading on one of the fusible links - focus on that link. You should definitely get 12v on 1 side of the link. If you get nothing on the other side, that link is bad. I'll attach the A-Zone diagram to help trace wires.
Corky

84redta

iTrader: (34)

I have an in-line blade type fuse holder with complete rubber housing for waterproofing...is there any reason why this wouldn't work to replace a fusible link. I mean all in all isn't it the same...but waterproofed in that rubber surrounding?

Also i've decided that my problem lied in that one lead that i couldn't get anything out of...my issue is that it has one input coming from the starter stud and within the fusible link switches to two outputs...

I looked it up for advance auto parts and napa auto parts online and they are showing generic fusible links, some are molded into the o-ring, some are in the middle, and some look like what i got in my '06 xterra with the little plastic casing around them, but none that look much like mine (other than the little square block looking inline fusible link, yet mine are round) and my second dilemma is that one input to two output issue...what do you suggest? Is there a rating on these fusible links? I've been studying these diagrams, between what you sent me and what is on the tech page ('86 wiring diagram) and it seems to be a bit of link A and B...could that be the two output part??? And in the diagram that you provided above, what does fusible link rust mean!?

~Jon~

1991ON20's

i remember a while back in the TBI forum. --->some guys open air element was touching his distributor..... and he fixed that problem and he was up and running.....i dont remember if he said he got a stench but maybe its worth taking a look.

Fullsizewagon

You could use the Maxi size blade fuses (they go up to 80A) instead of a fuse link, although they blow quicker than the links. Fill the holder up with silicone grease/ paste (non-curing) to ensure water proofing.
The fuse links are just a piece of smaller gage wire, but they are Hypalon insulated for fire proofing. Choose a link size that is 4 gages smaller than the wire it's supposed to protect.
Here is some info I found on fuse links, but the colors vary between manufacturers, and could all be rust..

Gauge color GM part #
20 gray 6292997
18 blue 6293702
16 black 6292996
14 gray 6292995
12 blue 6293923
10 rust 12077140

The two wire output is simply solved by crimping the two wires into one side of a butt splice and the link into the other.

Congrats on observing the distribution block & the C100 firewall connector! I believe they are the sources of many problems, as can be seen in this file:
www.wire-works.com/downloadfile.php?filename=Pg78-BC(96)TechTips-FAQs.pdf&id=18

You seem like a bright, observant, & resourceful guy so I'm sure you'll find & fix this problem easily.

84redta

iTrader: (34)

I don't know it all, but I do try to absorb as much information as possible. But thank you,

As far as the fusible link, I found a packaged one in Advanced Auto, but it used the smaller (red) crimpable cuppler, can I cut that off and use a bigger coupler (blue) to accomidate the two wires or should I use two of those fusible links instead of the one that GM put on the vehicle? (I don't wanna blow $4 if it can't be done, if it would just be safer with two instead of one?)

As far as color, it seems as though they are all black. I have one in a distribution block by the battery, and three underneath bolted to the starter stud, yet when I took a look at the tech page at the power distribution of a '86, it seems like there should be 5 fusible links (while I found 4)...could this single input/double output be "two" fusible links? This would explain why I'm having issues with some things on fusible link A and fusible link B, but i don't know if one is pig tailed off the other, so killing one killed both. Any input is appreciated. Thanks!

84redta

iTrader: (34)

as far as the distributer and air element, the issue wasn't until i moved the fuse block and received a big spark. I will look into this though! Thanx!

Fullsizewagon

You can cut off the red and use a blue, but fold the link wire double to fill up the extra space for a reliable crimp. The factory was thinking just like you and wanted to save a buck, but I would install two links. That way the other circuit would still work if the other blows. The factory would not pigtail two links, for cost reasons and to avoid the extra voltage drop.
I guess there is sufficient remains inside the blown link to estimate the gage, never mind the color.
But do investigate the lack of voltage on either side of that link, one side should definitely be hot as it is wired straight to battery/ starter.
If replacing a blown link doesn't fully resolve the problem, I would measure the voltages on either side of the 3(?) big red wires passing through the C100 firewall connector. They should all be hot always.

84redta

iTrader: (34)

Got the fusible links, will be putting them in tomorrow/saturday, thanx for the input. It seemed as though chevy wanted to save a buck putting the two together, but i'm not an 80's tech, so i didn't know if there was a purpose of why they didn't want one running without the other. The fact that i didn't get a votage is probably mearly becuase i didn't get all the way through the casing. It's unconfortable when you don't have a jack in the right garage where the car ends up, and the jack you can find leaves the car up against your chest as you slide underneath with no room to move your arms, lol. But at this point, i'm not upset to just replace these fusible links and never have to crawl underneath the car ever again for quite a while. Yet the fact that i only got like .3 MV off the output with 12V at the stud on the starter...i'm willing to put my money on that link.

What's throwing me off is that is it a regular thing for the casing to melt and be disformed to show that it was blown!? After reading that from one of the first replys, i was confused as mine all look perfectly fine. Then again it was mearly just one little wire grounding out...anyways will replace out that one input/two output fusible link with two fusible links and go from there. Thanks!

84redta

iTrader: (34)

I want to thank you all for all your help...(thank you corky for the wiring diagram, it definelly helped)

UPDATE...

Car works, it was the fusible link i had already been questioning. Of course GM is awesome...they took a crimpable battery terminal and put 2 fusible links into it and then on one of those fusible links, which forms the fusible links A and B, which is your primary IGN powering inside the car, and put that all in one fusible link with one input and two outputs. Gotta love how cheap they can be, cause i don't see inovation in that idea...Neways, purpose for ranting...

Has anyone ever heard of 2-3 inches of wire just disappearing inside it's insulated casing??? I swear to god i'm not making this up, the car worked before that big spark, and now from the battery terminal up to the fusible link, it is missing wire. This is why i got no voltage on either end of the fusible link, because there was no wire with power going to it, for all i know the fusible link could still be good if it had enough wire on each end to be used...but yea 2-3 inches just vanished...is that even possible!?

P.S. car is up and running and thank you all again!

Fullsizewagon

Great, congrats!
I once shorted a car battery with a relatively thin wire, on purpose, and the wire just exploded and vanished. I don't remember if the insulation was present though. But I guess it's possible that the metal vapor finds its way out the ends without rupturing the insulation, and it happens so fast that the insulation doesn't have time to melt.
(Btw., pulling on wires is a good way to test for integrity. If it stretches then it's a gonner.)
It also shows how important it is to disconnect the negative battery terminal first, so the wrench doesn't explode in your hands while disconnecting the positive.. Hands up all those that got just a spark and a scare while disconnecting the positive first, or connecting it last..

84redta

iTrader: (34)

I was just curious cause i didn't see the point of a fusible link when the wire would just evaporate like that. I guess thats what original 1988 wires will do for ya :-p Newayz thanks everyone for all the help!!

thexyzaxis

1 five gallon of gas + 1 match = problem solved :P

84redta

iTrader: (34)

can't agree more, lol, that works in a lot of situations...then again $3.00 a gallon seems steep, maybe 1/2 a gallon :-p