I have this problem with my 2006 Ford F-150 5.4 FX4 Screw. My truck randomly doesn’t start, and loses power, but all I have to do is disconnect then reconnect the negative terminal connector, and it starts. Any of the below actions might be related in causing the problem.

In October, my battery was terminals were horribly corroded. I cleaned them, then went to reconnect the negative and the OEM negative connector broke as I was tightening it. I decided to replace both positive and negative connectors. I cut the end of the three positive cables and two negative cables. I attached cable lugs to the end of the cables after stripping each end of the cable. Crimped and wrapped electrical tape around the lug and cable. I bolted the lugs to the respective new positive and negative connectors. I then applied dielectric grease to the terminals and connectors, and attached them. Truck ran and started fine, no problems.

About a month later in November, I removed the negative connector from the terminal, then removed the maf and throttle body and cleaned them; I disconnected and reconnected the necessary electrical connections when removing the maf and throttle body. When I reconnected the negative terminal, the truck wouldn’t start. The battery tested low with my multimeter. I charged the battery and tried to start, but it wouldn’t. I went to remove the battery and the negative terminal was smoking and the connector had small burn/blacks marks on it. Battery was only two years old. Took battery to Walmart, they tested it and said it was dead and replaced it with a new battery. Installed the new battery. Truck ran and started fine.

Then a few weeks later on December 9, my truck suddenly wouldn’t start and had no power. I thought it may be the battery, but disconnected it, tested it and it was fine. I reconnected and it started right up. Later in the day, it didn’t started again. I disconnected and reconnected the negative, and it would start right up. For the next few days, it would do this about every three starts. On december 12, I replaced the lug on my ground cable that connects to the negative connector. I had used a slightly too big of gauge cable lug and it was kind of loose. I got a smaller gauge lug and crimped it on the ground cable. I wrapped in electrical tape, and reconnected the new lug to the negative connector. The problem went away and my truck started every time, multiple times per day with no issues, until today, eight days later. It wouldn’t start and had no power, I disconnected and reconnected the negative, and it started right up. I checked the lug on the ground and it was snug on the cable.

Not sure what is going on. Any help is appreciated. I thought I fixed the issue, but apparently not.

 

I would have soldered instead of crimping.

 

I'd suggest redoing both your negative and positive cables. Making sure the wires are clean. Providing you are crimping them correctly and have clean cable (not dull or corroded) then soldering shouldn' be required. Do you have any pics?
The arcing you mention is simply a poor connection, either from dirt/corrosion between the post and terminal (unlikely since you have a new battery now) or the connector is not tight enough or cable is not clean.
A great way to clean battery corrosion is by mixing a tablespoon of bi - carbonate soda with a litre of boiling water and letting the parts soak until they stop reacting. Or pouring the mix over the terminal.

Hope that helps you.



​​​​​​

 

I was thinking the arcing might be at the crimp. Soldering eliminates that possibility.

 

I agree replace your cables and terminals . The idea of putting grease or other stuff on terminals is to keep air off them to slow corrosion.. You probably used those cheap connectors instead of oem type . Use high grade leads- clean terminals very well - put together then put some hi temp grease on outside of terminals .use good size multiststrand wire . Don't put anything between contact points . dielectric compound in series with a 12volt connection is a bad idea .
if you don't use some hi temp stuff it will just melt away in the summer . you shouldn't make your own leads unless you have the right skills, tools and materials .

 

And clean the frame or engine ground..