Featured Technical Trouble shooting

I'm always amazed when guys throw out "alternator" in a no start conditon. That might be if the alternator crapped out yesterday and he was running on the battery for quite a while yesterday or if the charge wire from the alternator wasn't making good contact and the battery wasn't gettng charged. A blown diode can result in a circuit that in turn drains the battery though. Still you don't need an alternator or generator for any engine to start and run.

Either a bad connection that is probably on a ground wire or a bad neutral switch is my thinking.

 

That aint the best idea as it can easily take out the diodes. I just bought one of these on amazon. I have a nice multi tester but these inductive amp meters are worth $35.

The alternator is suspect but needs testing rather than replacing. I had a Camaro that would go flat overnight but only sometimes. Other times it would be fine for weeks. Alternator had a bad spot where it would stop occasionally and kill the battery, it was like Russian roulette until I finally replaced it.

 

Not enough info.

 

Unlike generators or starters, alternators can't have 'dead spots' because of how they are constructed. What your problem was would probably be a malfunctioning regulator. If the regulator 'contact' that supplies power to the alternator rotor fails to open when the car is shut off, that would pretty quickly drain the battery. There is a remote chance that it could have been some sort of intermittent failure in a diode, but those usually either work or they don't.

 

HRP gave us a big clue; it was fixed in 30 minutes. That precludes any parts replacement unless somebody just happened to have a spare in their trunk.

Bad connection in the battery cables is my bet, but a bad connection in any case.

 

On purpose

 

Loose nut behind the wheel?...No, that's not it.

I'm going to place my wager on operator forgot to turn the battery disconnect back to the "on" position. Been there, done that more times than I care to remember.

 

The alternator can charge just fine and still have some bad diodes that will run your battery down! My Jeep has been doing it for years, I just unhook the battery , when I get out of it, as I probably won’t drive it again for many days!






Bones

 

@HOTRODPRIMER
Is a old Hot Rodder , many cars/ vehicles. The Sedan built 40 yeas ago ,
Over years his sedan he has added some
Modern up grades One I believe Ac,
Maybe a CB @ one time , doubt now.
Maybe a Radio possible bad , a draw,
Amp / Eq bad & draw , We know it's electrical issue, I am sure H R P did not use a sheet metal screw's for Ground & Hot's , Over years seen weird things , Its possible The Original batt went bad , New batt bad , seen many lately I do fleet & equipment repair .
I seen bad ignition switch Key on dash
Or bad switch key in Column , my 91 Gm with 80k has bad /out adjustment switch some times go to start No click ,
Will get to some day . yada yada.
I think most of Us rather with a issue Not work /Break instead of Intermittent! Especially when you're away from your toolbox .
Do not know Location of H R Primer
Batt , Mine under car , Not a floor Access.
& afew years ago H R P was locked out of his 32 & Pretty much Impossible to get into to Unlock unless break glass
Locksmith only option unless spare Key

 

But it was a one wire Alt. Still could have been the internal reg. Good point CS

 

If the battery checks out as fully charged, start a continuity check from the negative post on the battery to the first ground, then through the ground straps and wires. For me, it's always a bad ground, somewhere, just not where I began looking. I absolutely hate automotive wiring!

 

I guess I'm dating myself...perhaps it wasn't a good idea even in the 90s with a seventies vehicle...probably get a code nowadays...

Here's a guess, reversed positive and negatives

 

Battery cable corroded inside.

 

Ok guys, Lost Angel nailed the problem, I had a bad ground, it was the ground cable from the battery to the frame.
Obviously went I removed the 7 year old barrety from it's resting place under the car in a battery box in had to leave the battery connected because I couldn't access the side post attachments, replacing the battery I must have moved the negative cable enough to make proper contact and that work fine until it didn't anymore, it could have been a bump that caused the bolt holding the ground wire to lose a solid ground,

Tighting the bolt cured the problem, the car has been built more than 40 years and you guys know the old adage, "Out,ta sight,outta mind"

Monday I will remove the rusty bolt and sand the area around the hole and I replace the bolt with a new one along with a star washer, then it should be good for another 40 years. HRP

 

Me too!
Post #11

 

Credit where credit is due, I totally missed your reply. HRP

 

Add some dielectric grease to that connection to keep moisture and contamination out, glad it was an easy fix.

 

Need to know a bit more info . What is battery voltage ? Is the battery charged or deader than the doorbell ? If the battery is dead , you have a parasitic draw somewhere , most likely in the charging system . If the battery is charged , time to attach a volt meter and watch voltage as you hit the go switch . If the voltage drops below 9.5 new battery is bad . No drop starter relay or ign switch not suppling signal voltage to engage the starter . Not sure if you have manual or auto trans , if auto trans do you have neutral switch ? It could be failing , if you have one . I guess easiest is to test light on start wire at the relay , when switched to start , if it lights wiring issue is not the problem .Dirty or loose ground cable connection very easily could cause the issue if the battery voltage stays high when the starter is ask to start . Just my thoughts on starting , the investigation to local where Mr Murphy has moved in . Good luck my friend , this is not fun with cars at the moment for you .

 

See @HOTRODPRIMER's last post...sorry Dave, second last post above...

 

Bad ground strikes again. Funny how all that metal representing the negative side of electricity gets sabotaged by the fact that one piece of tin isn't rubbing up against another piece closely enough to pass electrons.

 

Ground wire ?

 

I vote for ground problem too.

Once upon a time, I had a crusty old '56 F-100 with tired 394 Olds and after a year or more of daily driving it developed a similar problem.

Battery was grounded to the frame; but the motor was not and suddenly whatever was making the necessary engine ground decided to not carry the juice.

Ended up clamping a jumper cable between the engine and negative terminal to get home and added a cable between the frame and engine the next day or so.

That particular electrical gremlin was abated for the rest of the time I had that truck.

 

There's are several Hamber's that actually nailed the issue...great troubleshooting ya'll

 

I worked in Aircraft. Someone mentioned Dielectric Grease. Which is a good idea...


Even better...
What we did was bond the area (polish bare) for the cable end and abrade the cable faces. Clean all 3 surfaces with isopropyl alcohol fasten and tighten to an acceptable torque and use an electrical friendly sealant to encapsulate the bonded joint both sides so there is protection from corrosion. I noticed the drywall screw specials shared there was one pic the abraded area looked the way it should. We used piloted round bonding wire brushes to abrade.

Is my negative ground done with sealant or dielectric...no but it would be a much more foolproof connection...

 

TA-DA!!

 

Don’t use a “ star washer” , they have been outlawed in the Firetruck industry! They have a tendency to collect moisture and cause corrosion leading to a bad connection!




Bones

 

You can never have too many ground straps. Body, Frame, Engine !

 

This was the main ground cable coming from the battery. HRP

 

Ok guy's, some say use dielectric grease and others dismiss it, what could possibly be wrong with using it? I honestly don't know. HRP