Electrical Guru's, I need help

I am chasing an electrical gremlin. What could be the cause of a random, momentary, total loss of electrical power to my truck? It can last anywhere from a flicker to half a minute. I lose all power. When it resumes, the truck starts right back up.

It's a '54 Ford truck with a 6 year old painless wiring kit. The wires all look good and are not cracked or brittle. I have replaced the battery cables, ignition switch and cleaned all of the grounds under the hood. The battery is old but holds a charge and always starts the truck, cables are tight and not corroded. Alternator shows a charge of about 14 volts running and 12 at an idle. Sometimes wiggling the battery wire at the solenoid works, sometimes not.

Any ideas are appreciated.

Conor

 

I would guess a problem in the solenoid, since that is where all the power goes to to begin with.

 

Does it have an ampmeter? If it does all power except to the starter p***es through it and I have seen them overheated to the point they cause an intermittent open circuit.

 

Solenoid was my next replacement purchase. Do they intermittently stop working before total failure?
It has a volt meter, not an ammeter.

Thanks for the quick replies.

 

Check your battery + wire isn't chafing momentarily on anything grounded ( been there) and check you have a good ground wire back to the battery also.

 

I would say that anything that you can 'wiggle' to get it running....needs replaced.

It only takes a tiny gap to stop electrical flow. A lot of those old solenoids were made of 'Bakelite' which can deteriorate with age.

JG

 

Delco and Interstae batterie with side post. They seem to have a problem with the post breaking inside the battery. Tel tel signs are liquid running down from the post. $0.02

 

First things first, to start with your 12 volt battery is supposed to be charged ( normally) to around 13.6 or 13.7volts. If youve got a battery thats showing you 12 volts on a VOLTS guage, that battery is weak ( or low on reserve power) Try a full charge on the battery and then do a load test on it. Most auto parts stores have a load tester that will tell you if the battery is dying when there is a load placed on it. The part where you say the volts guage reads 14 volts running and 12 volts idling doesnt sound right. it should be reading 14(or dam close to 14)volts all the time IF the charging system is up to par and the battery is holding the charge the charging system normally gives it. IF you suspect a short in your system hook up an AMPERAGE gauge or an ****yser to see if there is a current draw with the key off. Is this a Ford starter relay or a GM solonoid /engine in a ford? Could be a solonoid internal contact failure.

 

Is this just during start up? Must be just during start since you are considering replacing the solenoid and it isn't in use while the engine is running. If so, are your battery terminals clean? My Jeep randomly wouldn't start last year, but a smack to the battery cable would correct the connection. Cleaned the terminals by covering them in baking soda and adding water.

If the engine dies while you are driving, then you are looking at a loose connection.

 

i am with the loose connection point of view. if the solenoid does not allow a good tight connection toss it a new one costs like 10 bucks and you have probably had more than 10 dollars worth of aggravation...

 

If you are looking for a short or a place where electricity is being grounded where it is not supposed to be, mix up a salt-water solution with tap water and table salt. This is a electrolyte and will conduced electricity. Put the solution is a spray bottle and spray it onto the electrical harness at any suspect places, including the ignition system/distributor/spark plug wires while the engine is running. If there are any problems you will see sparks or the car will die. At this point you should know that where you sprayed it, there is a short or an arc.

If this doesn't work, check any components that are installed in the ignition circuit. This could include neutral safety switches, security systems, etc. Check these components with a multimeter to make sure that they are operating within their limits, even when you wiggle wires and components. Also, it is preferable to make these checks during a time when the car is acting up, you're more likely to find something.

Hope this helps, and good luck!

 

Thanks for all the great replies. I think I'm going to go with the solenoid failure. I know the battery is weak. However, I don't think it would cause the truck to lose all power on random occasions, then come back on and start right up.

I'll let you know what happens.

Conor

 

Solenoid should not cause the truck to lose power.

The main power leads feeding the truck coming off the solenoid.....those will make it lose power. You can't crank the truck if the key isn't powered, and key power comes from the small wires piggybacking the battery cable on the solenoid.

Turn the truck's headlights on and the garage's lights down so you can properly identify a flicker from underhood, or underneath. Get a helper to watch the lights if needed. Wiggle the **** out of everything til you find the loose connection.

What's happening just does not sound like component failure.

good luck

 

You have an open connection not a short. Like was suggested earlier. This should be common sense, sounds like you found the open connection already. If you can "wiggle" something and have the power come back, you should replace if not repairable once diagnosed.

 

If it croaks while you're starting the car, just totally everything goes dead, my bet?!?
Battery Ground is no bueno. Next time it does this fool with the negative post and make sure that it's solid on there and that where it's grounded to is good.

Please let us know how you solve it. Gotta hear the end of the mystery, like a story, ya know?

 

This is not a battery problem it is an owner/maintainer problem.
They don't put those little hexheads on those post bolts for any reason except to give you a hint that these aren't toppost ringclamps and can't be tightened until your full body weight is on the wrench.
Even the purpose designed post tightening ratchets are small with only a 4-5" long handle so you shouldn't crank 'em down more than snug.

Another owner driven problem is buying replacement bolts that are too long. There are at least 3 different lengths of these bolts from about an inch long to 2"+ depending on how many wires attach to that post. Get the wrong length and you can break out or twist the contact cup in the battery side...leak...no warranty...oops!

 

My favorite intermittent issue I have seen like yours was very similar except the driver stated it would happen in turns. Most of the battery checks mentioned above are great starting tips that should be checked anyway!

What my problem turned out to be was the ignition key. The driver had one of those key chains with 50 pounds of **** on it that pulled and wore out the switch. Going around corners would swing all that **** around and break the connection.

Typically when it comes to electrical all a car need to run is coil power, this usually travels through the ignition switch. (a electrical fuel pump could be another factor that might be cutting out, then restart after cooling down, however there is a difference when the pump stops running and the car engine is starving for fuel versus the coil, typically banging on the pump will get it going again, and it should be audible).

If it gets crazy and you just can't find the issue, wire in a light bulb (in parallel) to the suspected circuit (like the coil). When the light goes out, you know that circuit has lost power when the bulb goes out, or if it stays lit, go to another circuit.

my two cents.

 

here's one thing to check on the solenoid. I had one that looked completely tight, until you grabbed the threaded post and pulled it out. However, the other wires should be tightened on the same post as the battery + cable, and therefore, power should go to the lights atleast....in theory. I would try another battery, or have the current one tested at the local part store as recommended. I do know finding fusible links that went bad (if you are unsure if it is a fusible link as the culprit) are a PITA

 

http://www.jalopyjournal.com/forum/showthread.php?t=329145&highlight=electrical+trouble+shooting

this refers to shorts but theory could be used for opens also.

Does that harness or fuse box have a breaker installed someplace?

carry a meter with you and start checking when it acts up.
One off these times its not going to self correct so then you will need a cell phone

 

Total power loss is going to simply be an open or a BIG short. If it is a short, it would be so big that in the half min that the blackout occurs, something would be burning.

You certainly are getting an open somewhere. As already stated I would start with the grounds. IMO, the solenoid itself is not the problem, because with the exception of when you are actually starting the car, the solenoid really only serves as a "junction box".. There could be a loose connection at the solenoid but to me it does not seem to exactly be the problem. Might want to check those battery cables again, even if you replaced them, the cheap chinese **** that is sold in most places can be bad and still look good, the ends do not always have good connections.

Also, make sure that you have a ground form the battery directly to the engine, and from the engine to the body and frame.

 

Thanks again for all the replies.
39 All ford - I checked the battery wires again and it looks like I have replaced a cracked, frayed American battery ground cable with the cheap Chinese version. Everything looks tight, no bare wire, but it is pretty wimpy looking.

Right now the battery is in the stock location under the p***enger floor and who knows what happens by the time I push my truck out of the way and peel back the carpet to access the battery. I might relocate the battery to a box in the bed. Can I ground the battery to the frame and the engine to the frame? Or should I run a ground up to the engine?

 

What none of the other replies have addressed is the design of this truck. 53 - 56 Ford F100 truck cabs are mounted in rubber and are electrically isolated from the frame and the engine. Problems like yours are common...the solution is to use bonding straps to provide a common ground between the cab, the frame, and the engine. Braided straps work best but any heavy guage wire is better than nothing. Good luck...

 

CharlieLed - The battery is grounded to the engine, engine to the frame with a braided strap. I don't have anything to the cab, I'll add one tomorrow just for luck.

Thanks, Conor