Background:


1993 Toyota Pickup SR5 EXT Cab 3.0. This morning on my way home, I lost the wing nut to my positive battery cable. Next thing I know smoke is bellowing from under the hood. I cut the engine and coasted off to the side. As I opened the hood I was shocked literally. The battery had come loose and the positive wires moved and met the battery hold down bracket. The two positive cables (1 for fuse box and 1 for starter) were melted together. The ground had melted to the outside of the fuse block. Also there was spots on the ground cable that the insulation had melted off and bare wire is showing.


Remedy:


I tightened down the battery and added a new nut to the positive terminal. I drove the truck the rest of the way home. As I was driving, the truck would start to cut out but would continue to run. I could feel this in the truck while also noticing the tachometer would bounce up and down as if it was getting power and then lose it. I bought a new 4 gauge negative and positive cable. I snipped the wire connector for the fuse box and used the supplied butt connector to get power from the new positive battery cable. (I got the cables from Orileys Auto Parts because Toyota wanted $400 for new cables.) Both new cables are run the exact way the factory cables came off to include new wire loom, electrical tape and heat shielding for the section of the cable nearest the exhaust manifold.


Problem:


Every time I hit a bump the radio will reset.( I know its not the radio) The tachometer will still bounce up and down and the truck seems to cut off and back on almost instantaneous. It does not loose enough power to reset the factory dash clock however.




What is going on? Is it another grounding problem or burnt cable I am not aware of? I looked at the power wire to the fuse box and it looked somewhat corroded but I just left it when I reconnected it to the positive battery. I am at a loss and I really don't want to keep driving the truck while it is doing this. Also It did not have this problem until after the wires melted and almost caught fire.

 

hmm, how does the fuse box look. i would turn the radio on with the hood up and engine idling and start jiggleing wires

 

oh and un related to the cables my truck back in the day did that when the coil was loose with the cut out and the tach going over bumps

 

The fuse box looks fine. none of the relays or fuses are damaged. The wire to supply power to the box looks ok. All I noticed when I cut the old connector off was that the wire was not copper looking but instead grey. I did what you said and started the truck and at an idle jiggled wires listening for the radio to rest or a shutter from the engine. No such luck. didn't skip a beat. I even tried to simulate a bump by kicking the heck out of the tires but nothing. I checked all my plug wires and coil and again nothing. tapping on the fuse box and the relays along with jiggling the free wires in the bottom of the box all did nothing. Thanks for the quick reply. I am going to crawl underneath and see if I can locate a second grounding strap or cable. BTW all the electrical in the truck still works ie. windows locks lights.

 

 

 

Well having only one main ground coming off the battery might be your problem.

At most you should have at least 2 one to the engine block the other to the body ( most often the inner fender)

The one going to the engine block only grounds through the motor mounts the transmission mount and the rear suspension.

All subject to flexing and moving which could cause the problems your having . You would have to kick your tire pretty hard you didn`t break any toes did you ??

Then with a short going going through the vehicle you could have hidden damage

Since you shorted the battery terminal no circuit protection should have opened

One of those things one step at a time.

 

Wyoming9, toes are OK for the moment because it was more of a mule kick. It seemed that the slightest bump would cause my issue so I thought the kick would work but it didnt. I had assumed there would be another ground to the body but I was unable to find it. Anyway I still have the original ground cable so I might use a good section of it and add a ground. Where do you think I should ground from? Would a simple ground from the block to the body or frame to body work best? Do i use the ground from the block where the battery cable is at? Also I have the 10 gauge pigtail off the negative battery cable that I could ground to the passenger fender.

Since all of my relays and fuses look good, I didn't pull any just a visual check, does that mean that I am safe to say I didn't fry any computer or sensors?

 

Well I seem to have solve the issue! I added a ground from the battery to the inner fender and another ground from the engine block to the frame. I have yet to notice the problem again. Thank you all for your help with my issues.

 

I was going to suggest those very same two changes early way way early this morning but since the mobile website changed I can't post from my Nokia/Windows phone at all. It keeps telling me

1. The message you have entered is too short. Please lengthen your message to at least 5 characters.


Which makes no sense to me because I'm usually making long replies.
This is longer than 5 characters isn't it lol

americanautowire.com
Grounding Tips

"The main cause of most automotive electrical problems is caused by a bad ground situation. Always keep in mind that a circuit has to be complete. This means that the current has to be able to travel from a good ground to the positive side of the energy source in order to operate. Do not rely on just the negative battery cable as the only ground; always incorporate a separate ground wire or cable from the engine block to the chassis."


The mobile site also has too much going on and it has greatly slowed my phone down with adds and the likes. It's pretty much ruined it for my phone.

 

Glad you got it figured out !!

 

Odds are that after a while you'll find that crimp connection in a not so hot condition, leading to a connection problem. Crimp connections are cheap and fast and not many things that are cheap and fast are good.
They tend to go bad because they are unsealed and exposed to water and air. I'd suggest at least cutting the end off of it (and anything else that's been crimp connected), slipping some adhesive lined shrink tubing on, then re-crimping the connector. When you apply heat to the shrink tube it releases an adhesive that helps seal it from the elements keeping the wire in good condition. Not all shrink tubing has the adhesive so you have to look for it in the description.

 

Thanks for the advice. I completely agree that crimp connections are not the best and I bounced back and forth between crip and solder. I decided I would crimp for now and cover with the shrink wrap. I made sure to use extra shrink wrap past the connection (about 1/2 in on both sides).It doesn't have the adhesive you are talking but but it will do the job. I am in planning stages for a 1uzfe swap so I am not too concerned with it not being such permanent connection.

 

Like Odin says ^^^...
On top of that, if you have fresh cable (un-corroded lugs and wire) I would use good non-corroding flux, solder to fill all voids and improve electrical contact between cable and crimp. I used an 85-watt soldering iron.
I did not have adhesive-filled heat shrink so I simply coated thoroughly with liquid electrical tape, then when that dried, I applied heat-shrink.