Starting problem......sometimes dead!

[northerngmc]

I am having, what seems to be an intermittent starting problem with my 69 GMC.

Truck is a 1969 GMC halfton, 305 from the late 70's, 3 speed manual. The truck has HEI, and an alternator with the external regulator elminated.

The problem is it will start regularly and cranks just fine. They all of a sudden, nothing, I turn the key and absolutely nothing. It happened last weekend. I had been out at my wood lot cutting trees and then stopped on the way home for gas. Put $35 in the truck and then it was dead. Radio would work but it would not even turn. Seemed funny to me that it would go from starting and cranking fine to nothing. I called my wife and she ran over with the car and booster cables. Started fine with the boost. I drove home 5 blocks and shut the truck off, the it started right back up again.

I drove the truck on and off all week without incident again until this afternoon. Same thing, I had spent the morning in the wood lot and then came home for lunch. After lunch went out to start the truck and nothing.

So I grabbed my volt meter. Battery was reading 12.6 volts. I checked my cables and they both looked clean but a little loose. So I tightened them both up, then boosted it to get it going. When running the volt meter shows just over 13 volts and now I shut the truck off it is showing 12.7 volts and will start.

I hooked my battery charger on and it went right over to 6 amps.

One more piece of information, I had the starter rebuilt last summer.

Questions....

1) How many volts should a fully charged battery show?

2) How many volts should it show when it is running if the alternator is working properly?

3) Why would it go from starting to nothing? It seems like when the voltage drops below a certain point everything stops.

4) What should the charge meter in the gauges show? Mine sits in the middle no matter what? Could it be out of the curcuit with the internally regulated alternator?

[ap2002]

im having a similar problem, my truck starts right up, but if I drive it like 10-15miles on the freeway and stop somewhere and turn it off, it will NOT turn back on!!! it will do the same thing as you are explaining, not a click or nothing... then I let it cool off for about 20mins and then it WIll start right up no problem??? i figured the starter or something is really HOT so it wont start, its done this 3times to me already, and all I have to do is just let it cool down for a little bit...???

[northerngmc]

Originally Posted by ap2002

im having a similar problem, my truck starts right up, but if I drive it like 10-15miles on the freeway and stop somewhere and turn it off, it will NOT turn back on!!! it will do the same thing as you are explaining, not a click or nothing... then I let it cool off for about 20mins and then it WIll start right up no problem??? i figured the starter or something is really HOT so it wont start, its done this 3times to me already, and all I have to do is just let it cool down for a little bit...???

Today it had sat for an hour when I would not start, and last weekend I had only driven about 2 or 3 miles when I stopped.

[Sammy]

Sounds to me like a bad connection somewhere. Several years ago I had a similar experance. Start fine till it got good and warm then die. Later nothing uness you jump it. That problem happened the same day I was moving in the truck. Come to find out the wires to the starter were rubbing against the exhaust pipe. When it got hot it melted the wire coating to the pipe. Cool down and it would start again untill it managed to melt enough insulation to keep it grounded to the pipe then it wouldn't start. I would in your case insure all the wiring to & from distribtor, Starter, Ign switch, battery are tight, clean connection & not making contact with a hot surface. Check also the black firewall connector could be not making contact on the terminals. Then if you find nothing I would look at a bad solenoid on the starter or defective ign switch. Also sounds like your bezel gage has issues. Hope this helps just a bit.

[northerngmc]

1) How many volts should a fully charged battery show?

2) How many volts should it show when it is running if the alternator is working properly?

3) Why would it go from starting to nothing? It seems like when the voltage drops below a certain point everything stops.

4) What should the charge meter in the gauges show? Mine sits in the middle no matter what? Could it be out of the curcuit with the internally regulated alternator?

[PanelDeland]

(1) 13.2
(2) 13-14 volts
(3)Battery may be bad.Have it tested with a load tester.(Any auto parts store should do this free.It may only show up as bad under load.)
(4) The charge meter on the dash may show anything.They are notorious for being off.Midway on a good working guage should be about right.It may be a bit over.Watch to see if it moves at all when the engine is revved.

[northerngmc]

Originally Posted by PanelDeland

(1) 13.2
(2) 13-14 volts
(3)Battery may be bad.Have it tested with a load tester.(Any auto parts store should do this free.It may only show up as bad under load.)
(4) The charge meter on the dash may show anything.They are notorious for being off.Midway on a good working guage should be about right.It may be a bit over.Watch to see if it moves at all when the engine is revved.

Thank you for the information.

[Wrenchbender Ret]

You are probably haveing a hot selenoid problem. A lot of selenoids had a problem with heat causing those conditions. Especially ones with aluminum wire. You can take the seliniod apart & clean & tighten all connections. You can get a high heat selinoid. You can get a heat sheild to sheild it from the manifold. Sometimes it's a good idea to wire in a Ford type selinoid in the circuit from the switch to the starter. That takes away the voltage drop through the switches & connections. The indicator on the dash has 2 fuses in inline rubber holders under the hood close to the harness in 2 different places. One or both of these are often blown causeing the gauge vto stay in the middle.

[72chevyman]

i have the same problem.... the trk been sitting for 6 month , I put a new flex plate and a 1 wire mimi starter and it was cranking over and back to try againand it didn't. my trk did this before that why i put the new starter in. any way to jump wire the ignition to figure if thats the problem??

[haysonj]

Originally Posted by northerngmc

1) How many volts should a fully charged battery show?

2) How many volts should it show when it is running if the alternator is working properly?

3) Why would it go from starting to nothing? It seems like when the voltage drops below a certain point everything stops.

4) What should the charge meter in the gauges show? Mine sits in the middle no matter what? Could it be out of the curcuit with the internally regulated alternator?

Battery should be about 12 volts when not running and 13-14 volts when running. The Amp gage in these trucks does not work when you change to a internal regulated alternator. you will need to get a volt gage. I have had starters do what you are saying and have found it to be the solenoid most of the time. You can take them apart and clean the contacts with sandpaper. but they really are not too expensive to buy.

[WorkinLonghorn]

I had one once,an older truck,and when that happened,which seemed to be about 1/4 of the time,I'd just crawl under there and wack the starter with a hammer,get back in the cab and it would start right up.I was dirt poor and drove it like that for a long time before changing out the starter/solenoid.
Personally I would have to ask,Did you buy that starter from AUTOZONEOUT?

[northerngmc]

Originally Posted by WorkinLonghorn

Did you buy that starter from AUTOZONEOUT?

NO, I had it rebuilt at a small shop that still rebuilds starters, alternators, and electric motors.

They have done great work for me in the past.

[northerngmc]

I do not think it is my starter.

I think it is either my battery or my alternator.

As some have suggested to take these to my local FLAPS for testing, well this is not easily done. I live in a small isolated northern town. Nearest actual GM dealer is 575 kms away. A couple of local part sources, but nothing that offers free testing.

Any suggestions to load test a battery?

Any suggestions to check if an alternator is charging properly?

[Bus Ted Knuckle]

Originally Posted by haysonj

The Amp gage in these trucks does not work when you change to a internal regulated alternator.

I dunno about that

[WorkinLonghorn]

You show a difference of about 0.3 volts between running and static. IMO that is not near enough and since your amp gauge is not showing a charging going on,and since your battery charger showed 6 Amps charge when you hooked it up;I'd have to assume your Alt or internal regulator are not working right.

[DavesRide]

Hook up a headlamp to the small wire (purple on many GM auto's) on starter and to ground. If it is bright when you try to start it and doesn't start, then your starter is bad. On the alternator side of question, Wwere you driving at one time ok and the other with lights on? If the diode trio start to fail it will charge just a little until it really needs it like when the lights are on. Fine in the day, dead at night. Just a thought. David

[northerngmc]

Originally Posted by WorkinLonghorn

You show a difference of about 0.3 volts between running and static. IMO that is not near enough and since your amp gauge is not showing a charging going on,and since your battery charger showed 6 Amps charge when you hooked it up;I'd have to assume your Alt or internal regulator are not working right.

I agree that the difference isn't enough.

Battery is now charged and reads 13.2 volts. Truck running it only went up to 13.5 volts.

Mystery solved I hope! The alternator belt felt a little loose so I tightened it up and now I get 14.4 volts at the battery with the truck running.

I am assuming it was slipping enough not to provide a full charge and with short stop and go trips I wasn't getting enough of a charge to maintain the battery.

[northerngmc]

Originally Posted by DavesRide

Hook up a headlamp to the small wire (purple on many GM auto's) on starter and to ground. If it is bright when you try to start it and doesn't start, then your starter is bad. On the alternator side of question, Wwere you driving at one time ok and the other with lights on? If the diode trio start to fail it will charge just a little until it really needs it like when the lights are on. Fine in the day, dead at night. Just a thought. David

Thank you very much for the suggestions. IF I have the problem again I will try what you suggested.

To answer your question, no I have not been driving at night.

Today in Fort Smith NT
Sunrise: 4:38
Sunset: 22:10

Add at least an hour of twilight to that I have not even seen darkness in a few weeks.

[ed2552]

but in December, you only have like that much time in light, right??

[89 crew]

If the armature is damaged in the starter and the commutator looses connection to the windings, it will not crank or even click if the rotation is right so the brushes are on the bad section when you try to start it.

[northerngmc]

Originally Posted by ed2552

but in December, you only have like that much time in light, right??

Yeah the nights are a little long in the winter. December we probably have 6 hours of sunlight, plus some twilight.

[northerngmc]

Originally Posted by 89 crew

If the armature is damaged in the starter and the commutator looses connection to the windings, it will not crank or even click if the rotation is right so the brushes are on the bad section when you try to start it.

Then would boosting it help? My truck would start when boosted.....

[70cst]

Originally Posted by Wrenchbender Ret

You are probably haveing a hot selenoid problem. A lot of selenoids had a problem with heat causing those conditions. Especially ones with aluminum wire. You can take the seliniod apart & clean & tighten all connections. You can get a high heat selinoid. You can get a heat sheild to sheild it from the manifold. Sometimes it's a good idea to wire in a Ford type selinoid in the circuit from the switch to the starter. That takes away the voltage drop through the switches & connections. The indicator on the dash has 2 fuses in inline rubber holders under the hood close to the harness in 2 different places. One or both of these are often blown causeing the gauge vto stay in the middle.

I had a similar problem with my truck and it was the lack of a heat shield. The heat cause internal problems in the starter and after I drove a few miles the heat would create a situation where the starter would not function until it cooled off. Most are unaware of this issue until they have had it happen to them. Your starter problem may not be related to this but Wrenchbender Ret brings up a very good point.

[89 crew]

Originally Posted by northerngmc

Then would boosting it help? My truck would start when boosted.....

If the boost amperage was great enough,(it will have to arc) I'm sure it will, all it has to do is complete the circuit with the next lug on the commutator. Once the circuit is made the starter will turn.

[89 crew]

On the last truck I had that problem with it drove me nuts trying to figure it out. If you want to test it next time it won't start, remove the starter, take jumper cables and hook the pos cable to the field connection and the ground to anyplace on the body of the starter. If it is still aligned with the bad lugs it won't turn. If you turn it a little bit by hand then hit the power to it, it will spin up.