Epic Fail

[hrosenthal]

I've spent a lot of time on wiring the past few weeks.

I got a lot of advice from the engine provider, FFR, and input from this board; but in the end everything made sense and was consistent.
I also wired the dash, which was pretty straightforward (or at least I thought so).

Yesterday morning I planned to connect the battery and test the lights, blinkers, etc.

After I connected the battery I was looking at the dash and noticed smoke. I immediately disconnected the battery terminals and investigated.

I found that one of the three red wires that were connected to the solenoid was completely fried. I haven't figured out yet which of the wires it was (I plan to look at that tonight).

I see three possibilities of which none make sense to me.

1. It was the red battery feed, which leads directly to the fuse panel and should have blown a fuse if there was a short.
2. It was the alternator wire which leads to the alternator (single post) which is looking for a direct positive battery connection.
3. It was the ignition wire, but the ignition was not turned on and the key was not inserted (no possibility of error there).

I ordered a new harness, but am seriously thinking of having a local hot rod shop take care of the wiring. At $500 a pop, I don't want to keep frying harnesses.

[michael everson]

Unlikely that you need a whole new harness. You have nothing to lose so start tracing the burnt wire. If its live to the fuse box, its not fused. I always use a Maxifuse between the battery and the feed to the harness.

Try replacing the burnt wire, then reenergize the system except put a fuse in line between the battery and the positive cable. I start with a 5 amp fuse. You may need to go bigger once you start testing the headlights and fan. Or use a battery charger instead of the actual battery.

Also if you cannot find the short, try removing all the fuses and power it back up and see what happens. Replace each fuse until the inline fuse pops.

[Timb]

From what you are describing look a for a short to ground...it could just be something making contact with the dash. Also no need to replace an entire harness for a bad wire just splice in a new one of the appropriate size

[hrosenthal]

Thanks for the feedback. My concern is that something else in the harness may be damaged, but I'll both trace the wire and look at whole harness.

[skullandbones]

How far along are you in your build? If you don't have the body on yet, you are in great shape for troubleshooting this. I powered up everything and did a test for starter. That's when I found there was no power to the starter. I found a body harness plug to plug was not making contact to one of the solenoid wires. If the body had been on, that would have been impossible to trace. Also, hope you don't have your wires in looms yet. If so, you may have some damage on wires running along side the fried one. You would just have to trace and verify their condition. Everything to the battery should be fused or have a breaker. Of course, there is the outside possibility that there is a wire installed on a wrong post or terminal. I would check that first with the wiring schematic on the fried wire traced from origin to end point. Sorry for your difficulty but it may not be as bad as you initially thought. Good luck, WEK.

[blueoval_bowtie_guy]

I helped a guy out with a similar problem in NE PA (before I moved to FL). Really heated up a couple wires. He had something cross-wired at the solenoid. No permanent damage. Make sure there is only ONE wire that comes off the battery that isn't fused - that is the BIG one that goes to the solenoid. EVERYTHING else needs to be fused (or use circuit breakers).

[Jeff Kleiner]

And that's why I always do my wiring using a low power (5 amp) trickle charger in place of the battery and do not connect a live hot battery until everything has been fully verified and tested. I recommend that all builders do the same. Good luck as you sort through it.

jeff

[acth4347]

Never thought about using a trickle charger Jeff but that is a most excellent idea. Bill

[Norm B]

I never thought of using a trickle charger. That's a good idea! I made an inline fuse lead with a couple of alligator clips. When I want to test a circuit, I connect the battery using the lead. I can vary the size of the fuse to match the wiring I am trying to test. Found it is best to use the negative side of the battery for this. Avoids the sparks if your alligator clip happens to touch something.
I agree with the others, sounds like you have a direct to ground short in that circuit.

Good luck
Norm

[Gumball]

Jeff - I, too, like the idea of a trickle charger... I used a small lawn tractor battery on my bench when testing the circuits for my recent wiring project, but the charger would have been a safer alternative. Great suggestion!

[hrosenthal]

OK, so I finally got a chance to take a good look at this.

First of all, my engine came with the solenoid attached to the starter and the engine builder told me to disregard the FFR supplied solenoid.

Also, I am using the FFR supplied Ron Francis Harness.

Because the harness was too short to reach the solenoid, I had to extend the four solenoid wires.

It appears that everything was connected properly, but the wire that got fried was the extension from the Red Alternator FD to the solenoid. The actual harness wire was not damaged.

So not I'm thinking I used the wrong gauge wire. I'm pretty certain I used 12 gauge.

As per the schematic, the red alternator wire does not go through fuse box.

Since it's a single post alternator and the Red Alternator FD wire goes directly to the alternator, (I assume the ground is wired to the engine).
This concurs (sort of) to the instructions by the engine builder to run a wire directly from the positive terminal of the battery to the alternator - it just uses the harness wiring, which I though was more elegant.

Should I go with the more simple solution and disregard the Red Alternator FD wire all together and simply attach a wire as suggested by the engine builder? (I went back and read the builders instructions and he called for a 10 gauge wire from the positive terminal to the alternator).

On a related note, the battery did spark on the negative terminal when I connected it. I was under the impression that this should not happen, but some online reading indicated that a minor spark is normal. I was a little surprised at this and would like to confirm that the spark isn't an indication that there is a problem.

thanks

[OCCPete]

You are running a wire from the alternator to the starter solenoid? There should only be two wires to the starter solenoid, the large wire directly from the battery and the "start" wire from the ignition switch.

[michael everson]

You are running a wire from the alternator to the starter solenoid? There should only be two wires to the starter solenoid, the large wire directly from the battery and the "start" wire from the ignition switch.

Not if he is using the solenoid on the starter. You need to run your positive to the fuse box to that location as well. I see no reason you cannot run your alternator wire right to the starter solenoid.
Mike

[edwardb]

Not if he is using the solenoid on the starter. You need to run your positive to the fuse box to that location as well. I see no reason you cannot run your alternator wire right to the starter solenoid. Mike

I agree with Mike. If you look at the RF schematic, that's in effect what's happening. The alternator feed is coming back to the main battery connection, whether a separate solenoid is used or not.

I don't have a separate solenoid on either of my builds (let's not start that debate again...) but I chose to make the connections behind the dash with a bus bar and a mega fuse on the alternator feed. Generally a good idea and surprisingly (to me anyway) not included or mentioned in the RF harness. DD's typically have a fuseable link.

[Eastcoastcobras]

Not if he is using the solenoid on the starter. You need to run your positive to the fuse box to that location as well. I see no reason you cannot run your alternator wire right to the starter solenoid.
Mike

You are right, I only have one wire off my battery (big gauge) and it goes to the starter solenoid, there all my power goes out and alternator goes in. Maxi fuse after that point and EVERY wire must be fused. If you blow a fuse something is wrong, don't just replace the fuse, find the issue first.

[Eastcoastcobras]

Oh and this isn't an Epic Fail. Wiring can be confusing sometimes and mistakes happen, that's what fuses are for.

[hrosenthal]

I finally figured out the problem here.

I'm not sure if this is normal, but my alternator always in a closed circuit, so power is always running through the alternator to battery wire, even when the engine is off.

As per the Engine Factory, the wire provided in the harness is not enough gauge to handle the alternator and they recommended a product that is a 4 gauge wire with an inline fuse.

I was able to finish the wiring successfully.

There seems to be quite a bit of current running through the alternator wire (I get a pretty big spark when connecting battery) and I assume this will be a big drain on the battery if the wiring isn't disconnected when the car isn't in use.

I am going to install a battery cut off switch to prevent the drain.

I realize that the battery should be disconnected whenever the car is stored for long periods of time, but it now looks like it should be disconnected whenever the car is not in use.

Am I thinking clearly here?

[Jeff Kleiner]

Your alternator is faulty and needs to be replaced. There are internal diodes whose purpose is to allow current to only flow FROM the alternator to the electrical system/battery. When one or more fail current can flow the other direction draining the battery (or worse, burning down the car!).

Jeff

[Norm B]

I agree with Jeff. Your alternator is bad. Either the diodes or, if it is a one wire alternator, the part that turns it off when it is not being spun fast enough by the engine are faulty.

Norm

[hrosenthal]

I agree with Jeff. Your alternator is bad. Either the diodes or, if it is a one wire alternator, the part that turns it off when it is not being spun fast enough by the engine are faulty.

Norm

It is a one wire alternator. The thing that puzzles me is that Engine Factory tells me that this is normal and not a problem, but I don't see how that's possible.
I'm going to replace it anyhow -- I'm just not comfortable with it the way it is.