Engine Wires Burning
 

So earlier last week I was driving the 67 GTO to my office and got a puff of smoke and when I opened the hood, the waterproof fuse holder(40amp) for the electric fan was melted, gone. This was the first electrical problem since the restoration. So I replaced the fuse and holder. Yesterday when out with the car, it just died completly while driving, I discovered the 30amp fuse at the alternator was blown and the fusable link(16guage)wired between the Black/red and red wires coming up from the starter, merging with the alternator wires was melter and broken, it's wrapped in the taped area on top of the intake manifold right next to the alternator. Once I fixed these items the car started right up and I got home. I cleaned the connectios this morning and checked what I could, I made it to a show and it drove well until about 5 minutes from home and it died again. The fusable link(16 guage) was super hot and apart. When I reconnected it it still woudn't crank, maybe the battery was drained, suprising since it started the car with no issue 5 minutes earlier. I messed with it for 30 minutes and the wiring still smoked at that splice of the black/red, red and smaller black/red wire running across the intake manifold. I tried to bypass the 16guage fusable link and smoke started under my dash, I quickly turned the key off and disconnected the battery. Now it's on a tow truck coming home. Any ideas why this is happening?

Notes:
All new wiring (M&H)
Powermaster 140amp alternator..M&H said too large but 2 mechanics said no,it's an "on-demand" system, sends out the amount of power necessary, I'm concerned. I still have a new 100amp alternator new in the box if M&H was right.
Powermaster Starter
461ci, 4speed, electric fan, A/C, aftermarket stereo and Alpine AMP and sub not yet hooked up.
Yellow top Optima Battery

Thanks,
Scott

Which electric fan and relay are you using?

burned wires aren't the problem, they're the result of the real problem that we need to identify. as for the large alt, m&h probably meant to say 'not necessary', but i can't really speak for them. i run 140 amp alts in both my cars with no issues. i would disconnect the stereo stuff and isolate systems til you find which one it is. the usual suspects are high amperage things, like fans and amplifiers. wires that are too small will cause resistance, that creates heat, that creates more resistance until fuses and links melt. how large are you fan wires? stereo wires? a simple short somewhere in the system (even with a low power device) can cause a heavy load on the system, and the 140 amp alt will do alot to push that load.

All of the high amp accessories need to be powered from the battery (or a junction block from battery) then through relays. Alternator output needs to go straight to battery (or a junction block from battery).

This way all the factory wiring stays intact and doesn't get any high amp loads. Only light duty work tripping the relays.

The 140 amp alternator is not the problem, it's how you wire it to the car. You just can't send that kind of power through a factory harness and power high amp accessories.

OE fuse links and power wires need to power OE equipment only. All the add ons need there own fuse links between junction block and relays.

This can be made to work and work really good, after you repair everything that got melted or burned.

The stereo is not even hooked up yet, I just noted it to state why I had the 140amp alt. How is it best to find the flaw, what am I looking for?
It's a BeCool rad and fan set up, single puller fan, the wire looks to about a 10 guage. I bought the set up from Summitt and a mechanic who works with the restoration guy I used installed it for me.
When I ordered the wiring from M&H I told him what mods I had and when I told him the Powermaster 140amp alt he said clearly, "it's too big, you'll fry the wires". I'm far from an expert so I went and bought the 100amp alternator and 2 people swayed me saying what the guy at M&H said was wrong.

Thanks,
Scott

Clay,
I don't have the stereo hooked up yet, the only high draw item is the electric fan, how can I test for the problem, a multimeter and volts? Needless to say I'm a rookie at this.
The electric fan does have a relay, I need to see how it was installed, from what you stated earlier, the electric fan get direct power from the battery or junction box, then to a relay, then to standard wiring, correct? So the relay drops the juice to an acceptable level?
I'm starting to think a tow down to Georgia may be my best bet, somehow I don't think my walet could handle that.

Thanks,
Scott

It's the Becool rad and the single electric fan set up, 12" I believe. No isues for the last 2 months, limited miles but still not a single issue, and now suddenly big problems.

"I don't have the stereo hooked up yet, the only high draw item is the electric fan, how can I test for the problem, a multimeter and volts? Needless to say I'm a rookie at this.
The electric fan does have a relay, I need to see how it was installed, from what you stated earlier, the electric fan get direct power from the battery or junction box, then to a relay, then to standard wiring, correct? So the relay drops the juice to an acceptable level?"

Scott,
It's battery or junction block to relay, then relay to fan. That way the fan gets full system voltage. The only load on factory wiring and switch is the low voltage required to trip the relay, which is almost nothing, say probably less than an amp.
I'm guessing now the main power supply to the relay is running through factory wiring, and that's whats causing the melt down.
First fix what's melted. Then add, if it's not there, an 8 guage wire from alternator output to battery positve, because of the 140 amp alt.. Then feed the fan relay from the battery or a junction block.
Nothing I can do that you can't do, just takes longer like this.
Check it out good and post back. If nothing is too bad inside, you shouldn't have much of a problem.
Comcast is acting up during repairs tonight, so may be off line till tomorrow, but will type as much as I can.
The car will only use as much power as needed from the alternator. So you can leave the cars power supply wire on the back of the alternator or move it to a junction block with the other wires, that's if you add a junction block. Junction block/insulated stud is just clean and neat, easy to add a new wire to, and un-clutters the positive post on the battery. Power supply wires from starter can also be moved to it.

Starting to blink in and out, they said midnight.
Try to decipher what I've typed and see what you can figure out.
Un-plug that fan and see if the wires quit smoking. Something may have done got melted together inside.

Will help all we can
Clay

Clay,
I drew a diagram of the way I saw the wires and where they are going, what are your thoughts? BeCool didn't have the scemantic for the fan I'm using on their web site, I will call them and see about getting one, I think the mechanic who installed the fan threw it away. I won't be able to do any repairs until the weekend, hopefully finding something wrong will give me piece of mind. Also, the wires didn't burn until the return ride home after 25 minutes of driving, so it's not like the problem shows up right away.
One note, the fan stays on after I turn the car off if it's still necessary, so if it's power is coming from the "yellow" wire, did he splice that in at the starter? It's not connected to the battery at the post, and I do remember him saying he liked to run fans from the starter, the car sits too low for me to get underneath without jacking the car, and I couldn't today. There is a large guage yellow wire coming up to the alternator, so I'm assuming it's from/for the fan, maybe it's not. The large yellow wire from the fan does go under the engine twords the starter area, and the yellow wire to the alternator does come up thru the block/P/S bracket area, so that's why I was thinking it's the same wire. I just wanted to add this so you had all of the info, I think im babbling on and on, sorry.

Thanks in advance for the help,

Scott

Very good on the diagram. Helps alot while reading your first post.
I see the fan runs whenever needed whether the ignition switch is on or not.
Nothing wrong with that really...at least not right now.
The diagram does show a couple of potential problems. Running power to the fan off the back of the alternator and where the 40 amp fuse is located.

Since it melted the 40 amp it probably needs a stronger more reliable fuse. That's best done with fuse link, or the new big high amp fuses, which brings up something else. The fuse/link needs to be before the relay.
Next; The alternator gets battery power from the starter solenoid big cable lug, along with the rest of the car from the big splice behind the alternator. If the car is off or the alternator isn't putting out enough, power has to come through the factory starter to alternator wire. At low speeds, especially idle, the 140 doesn't putout much more than a standard alternator. So looks like the reason the wires behind the alterntor melted was because they couldn't carry the load for the fan and power the car. In other words the alternator output stud is more or less a junction block for battery power when the alternators not doing enough.
All that can be fixed with a junction block off the battery (+) post to power everthing instead of using the back of the alternator.

By the drawing the fan didn't cause the wires to smoke going inside. So you'll just have to track them to where they go.
Don't know if the blown fuse link killed the car or more than likely one of the M&H factory red wires is shorted out draining all the power. Maybe down next to the starter, since that's where the power supply starts now. If power to the alternator was lost coming up from the starter, the alternator could have went into overtime thinking the battery was dead. That would've/could've shot way to much power (amps) inside the car and caused things to melt.

Need to know wire sizes being used on the fan and the fans amp draw starting up and running.

So check your red/black and red wires for shorts, and see what you can inside the car that smoked.

May sound bad but not that bad. Nothing that can't be fixed.

Tomorrow is my monthly trip to the hospital. Should be out-patient and back home tomorrow night. So weekend sounds good. Update whatever you find so I/we can be doing our home work on this.
Will be checking back in here today
Clay

Heres what it sounds like to me. you have a dead short somewhere, thats seems obvious from the drastic melting of the fuse holders. Likely a hot wire that has rubbed thru the insulation and shorting to frame or body or motor. Also indicates it is a BIG wire that is shorted. Smaller wires, 14g or under will usually burn thru the wire itself before blowing a fuse holder completely apart. That takes big amp wire and short like the starter cable or any other big fat wire such as the main from alt to bat.
I would work out from bat and from alt following wires. Somewhere a big wire is touching ground. It could be a wire you installed months ago that has taken this long to rub against a sharp edge and finally short out.
think back to the last work you did on the car, electrical or otherwise and then investigate the wiring in that area. Could be as simple as disturbing a wire next to where you were actually working that later shorted out. That could happen doing the simplest chore like vacuuming or changing oil or whatever.

So the wiring layout looks ok to you all, I shouldn't re-wire everything?
I will go thru everything this weekend and hopefully find something, I have a feeling there is a wire laying next to the headers or something, we also used the ram air positive cable sleeve to run the wires to the starter, maybe it's not doing it's job and things are getting hot.
When the car stopped on Saturday, it had been running for about 10 minutes and died while driving, it was the 1st time and it took me over 45 minutes to figure out the cause, once I wired the broken fuseable link together and rigged the ALT fuse wires together, it started and I made it home. On Sunday when it happened, the wires never coled down, maybe it just needed more time and I could have gotten it home, I played it safe and called the tow truck. On Sunday the ALT fuse didn't blow, but the 16guage fuseable link was busted and very, very hot.
When looking for a "bad big wire", can it be anywhere, or most likley near the problem? I ask this because I have a power wire going to the trunk to where the amp and stereo system will be, I'm pretty sure it's all taped up, but I'm looking to rule things out, what about under the dash?

Thanks,
Scott

There must be a dozen or more sharp metal edges that wire is close to on its way to the trunk. The factory used some goofy routing to avoid that problem. What looked ok when you installed it could have changed when the carpet/trunk mat was laid back etc. Maybe even as it comes in thru the firewall. Maybe not your problem but its worth a look.
Example of tried to do it right and didnt:
I put a stereo in a car back in the 70s and ran the speaker wires under the carpet 'to protect them'. When my wife was in the drivers seat the rock and roll was fine, when I sat down in the seat the music would cut out. My fat butt was just heavy enough to short the speaker wire under the edge of the seat mount. Moving the wire a couple inches away solved it.
I was lucky it wasnt a high current power wire direct from alt to an amp. We didnt have that stuff then.

I said the diagram looked good. I did not like how it was wired.
The 40 amp fuse was in the wrong place. It should have been before the relay.
If there was a short or just overworked after the 40 amp fuse, it should be easy to see. It's the wire from the fuse to the fan in your diagram.
Same thing still goes about feeding the fan through the factory wiring, don't do it. At low speed the alternator doesn't put out enough and power has to come up from the starter. With fan, AC, pretty much anything else on, it could've overheated the wire coming up from the starter.
If there's a fuse link in the wire from starter to alternator, and it melted, the alternator would've tried to charge wide open and could've started all the other melting.

Just can't use the alternator as a junction block, without adding a heavy wire from the alternator to battery positive post. Fused fan power needs to come from the same place. I'd add a junction block and get system feed wires moved up from the starter. Starter would only have battery cable and solenoid wire.

Got to figure out if the alternator lost power and started charging wide open or if
something got a short in it.

Need to know more about the condition of the wire from starter to alternator and did it have a fuse link that melted. If it did have a fuse link that melted, that could've started the whole problem.
Just have to look under the dash for anything melted.

Might take all the hot wires apart behind the alternator, hook the battery back up, then touch one wire at a time to see if/which ones shorted. That should narrow things down considerably.

This will fix, just needs fixed right.
Clay

I gotta agree with BVR421....I would first trouble shoot by disconnecting the fan completely, and seeing if the problem still occurs....process of elimination .. Good luck, Eric

Clay,
I looked at the wiring in the engine compartment yesterday and couldn't find and shorts, but I was a little confused on some of the configuration, I'll tell you what it is I saw and hopefully you can tell me if any of this would have caused the fuseable link to burn.

The electric fan is powered directly to the back of the Powermaster alternator.
The alternator is powered by the battery with a direct wire. Powermaster wire about 8 guage I think, maybe 6 guage
The alternator is internally regulated and the M&H wiring is made for this change and also for the MSD distributor.
There look to be 2 red wires coming off the starter, 1 larger red wire about 6-8 guage that goes straight up to the wrapped engine harness wires running on top of the intake(spliced right at the burn site)
One smaller red wire, maybe 10-12 guage that was spliced into a thicker purple wire that goes into the same engine harness right at the burn site. The splice is right at the Positive battery cable sleeve(the metal 4" sleeve/tube to protect the wires from the header heat) -This splice didn't look great and the wires are different sizes, but the wire was still taped and I coundn't remove it right then.
I know the fan was not wired correctly, and the fuse is on the wrong side of the relay, I just want to see if this is what caused all of the melting or something deeper. Since it dosen't show the problem right away, it can be a costly thing just to drive around for an hour or so until it possibly just dies, leaving me stranded and back to the starting point and with another tow bill. What fun!.

I'm also adding the wiring sheet from BeCool, the odd thing is the relay has 4 wires coming out, grey to manifold temp sender, yellow for battery, but there are 2 orange wires, 1 thick orange about 8-10 guage and one smaller around 12 guage. The guy who installed the fan wired the smaller orange into the large yellow wire going to the alternator. Since the orange wire was supposed to go to the 12v ignition switch and goes straight to battery, is this an overload on the system?

I'm totally ready to re-wire the fan the way the diagram says and add the junction box like you said, sorry about all of the questions, I just don't want to get stuck again and have to get a tow or worse, get into an accident because I can't get to the side of the road.

Thanks,
Scott

Eric,
The issue is the electric fan is the only fan for the car and since the problem didn't occor until after almost an hour of driving, I won't risk the motor by driving without the fan. Unless I'm misunderstanding your statement?

Scott

Scott,
The smaller wire from the fan relay doesn't use much power. The way it's wired now, instead of through the ignition switch, lets the fan run with key off. A lot of fans are wired that way so the fan will cool things down after you cut the engine off. I don't see that as a problem or having anything to do with the melt down.

The big wire from alternator output post straight to battery is good. I was under the impression that it wasn't there and system power was coming up through the red wires from the starter.

Those splices need looked at closer. Purple should be solenoid engage wire for starting. There shouldn't be anything spliced to it. If there really is a red wire spliced to it, need to know where it goes.
"One smaller red wire, maybe 10-12 guage that was spliced into a thicker purple wire that goes into the same engine harness right at the burn site."
Everything at the tube needs looked at really good. Thats a common place for shorts to happen.

Things were making a little sense......Finding out about the big wire from bat (+) to alternator has changed things. Need to know; how many wires were bolted to the back of the alternator and where did they go. With a wire from the battery to alternator, there wasn't any need or shouldn't have been any red wires coming up from the starter. Just doesn't sound right for M&H.

Driving is out of the question till this gets figured out. Oh...When did the wires smoke inside. Was that key on, key off, or? or? when you was touching wires together under the hood.

I'm going to re-re-read over everything again. Post back what you can find out about the burnt spot and the wires hooked behind the alternator.

Just need a little bit more to think about. Got a puzzle here with pieces missing. This all could be from a short to a lose connection on some wires.

Will be here
Clay

Clay,
I will drop the starter this weekend and see what I can find. Some of my terminolgy may be off, for the 2 red wires off the starter, the bigger red wire goes straight up to the engine harness, the smaller red wire is connected to the thick purple wire at the tube/heat shield thing, it looks like the purple wire was too short or something to make it to the starter, so they used the smaller red wire to make up the difference, I called it a splice but it does not branch off anywhere, that purple wire also goes into the engine harness. When the car died for the 2nd time on Sunday, I tried to fix the issue with a spare fusable link I had bought, but it immedialtly smoked when installed and the key "on", never with the key off ans anything smoked. I meddes with it for about 25 minutes and then tried jumping the 2 areas, basically I used a 10guage wire to join the 2 ends and that's when it smoked under the dash, after I turned the key on. I immedialty turned the key off, maybe 2 seconds and disconnected the battery. Thats when I called the tow truck.


I'm uploading some photos of the areas on top of the engine, maybe that will help identify some of the issues. Let me know your thoughts.

Thanks,
Scott

Few more photos
 

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Attachment 184125Hee are a few more photos that could't go into the last reply.