My 96 Bronco w/ 351 became hard to start and hoping to get some fresh ideas. It's got 233k miles so it ought to be real easy to turn by now.

Last night it wouldn't start... jumped it off and took it to AutoZone since I bought my last battery there. Anyway they tested the battery and alternator and said they were ok.

When the truck is running, I see the voltage meter in the dash is at 14+. When I shut it off, if I try to restart it within a few seconds, it turns over pretty strong and fires up. If I turn it off and wait a few minutes, it barely turns over. Popped the caps and visually checked the battery and the water level is good.

The cables at the positive battery terminal have seen better days but I cleaned them fairly well and reattached them. I don't mean just the terminals... the cables had corrosion under the cladding and had to be trimmed back a couple times.

I know, well, I think, there isn't much more to the starting than the battery, alternator, starter, and solenoid.

Does that sound like a problem that the starter could be causing?

Thanks,
Marshall

 

Seems like your elec. system has developed a parasite drain, have you installed any new electric parts or accesories later?.

 

It would seem so. Does letting my wife drive it recently count? Sure seems to drain my pocket.


No new accessories. Truck is pretty stock. I did forget to roll up the back glass and drivers window when our drought took a break about a week ago. Got pretty wet inside.

 

With the key off I seem to have a little over 12V but when I turn the key to the on position it seems to drop quickly to about 9V. I'm wondering if the positive battery cable has developed a lot resistance due to corrosion.

 

From teh sounds of it I would go ahead and replace the cables to be safe. Also remember when you put the key in ON position you are giving power to fuel pump, radio and such. So voltage drop isn't unusual, however I didn't think it dropped to 9 right off the bat.

 

Well I replaced the cable assembly that runs from the positive terminal down to the starter and also over to the solenoid on the firewall.

I found a broken wire - the little wire that runs to a spade connector on the starter - the connector broke off. So I was pretty happy that I found "the problem". Spliced on a new connector....

Jumped the truck off and I see the Volt meter go to 14+ in the dash. Let it run for a few minutes and stop it. Turn it back on and it starts easily. Turn it back off, wait about 10 seconds - try again and it suddenly acts like it's dead. DMM reads about 10.5 volts across the terminals now.

When the Volt guage goes to 14ish, it doesn't start coming down when the engine RPMs slow like it usually had done in the past. Not sure what that means

 

Don't forget to check the ground cables. Dead as in no power no lights or just cranks but no start dead?

 

Maybe after all the work, the battery only had enough power for a couple starts. Might just need a charge now.

 

Should have still been able to start with 10.5 volts assuming it was cranking.

 

All depends on how low it dropped when cranking...... I believe about 8.5 volts during cranking is min. for the rest of the system voltage to allow start..

 

Sorry... dead as in it barely has power to start turning over and quickly loses that.

I also cleaned the negative post/cable and re-tightened.

 

I'd love to believe that but I'm pretty pessimistic at the moment. I'll put a trickle charger on it when I get home.

 

Gotta verify everything to eliminate possible oddities......then try again.

 

Did they do a load test on the battery or just check voltage. The gauge in mine reads 16 volts when its running, but when i check it with a volt meter its only just over 14 so i dont put a lot of faith in the dash gauge.

 

Am I missing something ? I don't see where the starter was pulled and tested, or anyone suggesting it. Starters go bad, sometimes in peculiar ways. What you're describing is typical of a starter with a bad stator. When you've been driving, then you park and shut the engine off, underhood temperatures skyrocket causing a condition called Heat Soak ( Chevy guys with the starter mounted solenoids know allll about this ) The plates that make up the stator in your starter swell and bind causing massive amounts of internal drag....that's why when you shut it off for just a few seconds it rolls right back over, but give it ten minutes and it slugs. If you have the little reduction gear starter with the second solenoid mounted on the starter, you get even more voltage loss due to carbon buildup from the arcing of the solenoid contacts.

IMHO....the reduction gear starters with the second solenoid should be thrown away...They're less reliable than the Pole Shoe starters, generally have plastic planetary gears, and make it overly complex, placing a constant 12v+ cable right next to the hot exhaust. Who has a stock engine that has *so* much compression a standard starter won't turn it over ??? Just my .02 cents.

-Scott