Truck let me down at the last minute!!

[Dodger]

Hey all,

Was racing around today getting ready for rego inspection on the 50 3/4 ton including spending $440 on last minute front spring repair on a problem i hadnt noticed before this morning!

Truck drove really well but at the workshop when the mechanic went to move it inside - nothing at the ignition, no click, nothing. The gauges were working when the key was switched on though.

Threw some jumper leads on and it fired no probs.

Went back a few hours later and the truck started no problems.

Got it home for a last minute pressure degrees/pressure clean and no ignition again and this time no good with jumper leads. Battery(brand new) seems dead.

So, it starts when cold but not when hot.

The new battery was fine for weeks of turning the truck over out the back but after two long runs, it now seems dead.

Any ideas. I was thinking faulty starter, solenoid, alternator or a bad ground somewhere.

Any ideas?

Very disappointing as today was rego day!!
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[lazypineapple]

Volt meter to ck is batt dead ?
Yes?
Charge it up
Ck for drain on batt.
Not dead?
Ck voltage at starter
Ck voltage thru key switch
Ck voltage thru neutral safety switch if automatic
Double triple ck all connections and grounds.
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[1project2many]

Once upon a time GM starter rebuild kits came in 12 and 16 ounce versions with an ergonomic hickory handle.


Seriously, old school GM starters act up when warm. Use a test light to check for power at the battery cable connection at the starter, then at the solenoid while someone is turning key to "start" position. If yours is bad, you may be able to use a late model "gear reduction" type starter to replace your old one. They seem to last much longer.

Please, please, ensure the truck is blocked, jacked, braked, disabled, etc so it does not accidentally start and move while you are laying underneath.

[mrsmothers]

Would bet a million dollars it was the starter.

[Dodger]

What about alternator?

The battery is brand new and should be all good.

I put a battery from another vehicle in the truck and it started right up, but it had cooled down by then.

From what I gather, is the battery was even slightly down, it may not engage the solenoid to start the engine, and maybe getting hotter makes this problem worse at the starter, solenoid end???

After a quick look at the altenator I noticed that the plastic connector is unplugged and hanging at the back of the altenator. What is this connector for? It doesn't look like it fits into the slot where the pins are.

I know there is a live pin inside the connector as it showed an arc at metal. Could this be preventing the alternator from charging my battery?

Felt like taking the hickory handled kit to it today that's for sure!
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[mknittle]

"I put a battery from another vehicle in the truck and it started right up, but it had cooled down by then" Been there done that.

As 1project2many said. One problem that is common is if the exhaust is close to the starter the heat will make the starter act up. form the factory V8s had a heat shield mounted on the starter that seem to come up missing over the years.

[Dodger]

OK, makes sense but I'm trying to come up with a reason why the new battery has been flattened and only after I do two longer runs in the truck. Just starting it in the shop whilst working on it for different reasons has been no problem over the last three weeks.

This morning it started strong, cold with no issues. Took it for the longest run its had (about 40 minutes at 40 to 50MPH and nothing at the ignition, no turning over and no click.

It started with jumper leads.

A couple of hours later started strong again and after another 40 minute run, nothing at ignition.

Tried jumper leads but battery was just too dead.

1 hour later with a different, fully charged battery, started strong again.

Strange.

So if the issue is heat on the starter, why would by battery be dying?

Any ideas on a solution for the heat issue?
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[Katrina/10]

Sorry to hear you had probs on the big day, I know you put a lot of work into getting it ready. Take a close look at the starter and check all the wiring around it with a test light and a helper.

[RedneckRodder]

I have a Toyota that does the same thing. I get no click from the solenoid, so I originally assumed the battery was dead. Fired right up with jumper cables.

Same problem next morning, I hit the solenoid with a large object, let's call it a hammer: truck fired right up.

Use a digital multimeter to check amps on the battery next time it happens, chances are your battery is fine. Just like everyone else has already said, those old starters don't like heat. Very, very common in old Chev's.
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[Dodger]

Cheers all,

I'll start working through the things suggested.
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[Russell Ashley]

Are your battery posts and cable ends clean? It sounds like it could be a bad connection at the battery. The next time you think the battery is dead, meter the voltage on the battery posts, not on the cables. It's unusual for a good battery to go from charged to completely dead that quick. I would clean the posts and inside the cable clamps, and make sure that they are tight when you tighten them.

[mr48chev]

If the exciter wire on the alternator isn't hooked up the alternator may not have been charging and you were running on the battery until it drained down to where it wouldn't start the truck.

Also as the guys said, a weak or suspect starter will often start the engine pretty well cold but won't crank it over when it's hot. You can often pull it off and replace the bushings and brushes for a few dollars and go again. A sticking solenoid could be the problem if it isn't kicking in right.

First you need to get the charging system hooked up correctly and make sure it's working and then you need to check out the starter and solenoid along with the wiring to the starter.

I've got a couple of diagrams of alternator hookups that I have collected in this album that you can look at and see how the alternator should be hooked up.
http://s173.photobucket.com/user/mr4...?sort=4&page=1

Running with the battery charged it should be putting out a bit over 14 volts.

[_Ogre]

most gm starters have a heat shield on them
it usually gets tossed the first time the starter comes off
make one and throw it on there

[oldcouple]

You might also check the starter shims.

[Zach B]

could be two problems at the same time. those old starters don't like the heat and if it has a bad alternator i could see why it would behave this way. try the starter first though.

[klutz51]

Voltmeter and test light, check at the battery cabel on the starter that you have 12 bolts when it is hot, make sure the s wire on the selenoid is gettng power on crank. Have seen battery cables cause this issue, start simple tests hope thi helps.