'94 350: good cold starts, struggles to crank when restarting or still warm

[usar17]

I don't care about factory haha I just want her to run good

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[thinger2]

My 94 has a bracket on the back of the right head that I through bolted my head to firewall ground to.
For a few reasons...
The ground on the back of the head is a ***** to get at
Its cold dark and raining
Total lack of ambition
I cant get the truck in the shop because I have Nissan guts splattered all over the place.
And, the big one..
Everytime I crawl my over grown Sasquatch ass over the top of the engine I break some essential plastic part

 

[usar17]

Welp....both cold and hot starts sounded strained this morning. But it is 24° outside. Time to get the battery checked again.

Safe to assume that months of heat soak starts can damage my battery's performance?

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[Schurkey]

Perhaps I missed it:
What is the battery voltage when the engine cranks slowly? For that matter, what is the battery voltage with no load? A fully-charged "12-volt" battery had better have 12.6--12.7 volts with no load, and at least 9.5 when cranking, but more likely ~11 volts. More is better.

Welp....both cold and hot starts sounded strained this morning. But it is 24° outside. Time to get the battery checked again.

Safe to assume that months of heat soak starts can damage my battery's performance?

From what I'm reading, you've gone to heroic lengths, doing everything except verifying one of the MOST COMMON sources of cranking problems--a discharged or failing battery. At minimum, you need to check open-circuit voltage and cranking voltage. Ideally, you'd have the battery properly load-tested.

"Heat soak starts" aren't likely to damage a battery, since the heat-soak tends to increase resistance which lower current draw. But anything can happen.

 

[usar17]

I need to get an assistant to check voltage drop at crank. I grab the voltage while off. And the battery was load tested at AutoZone back in June, listed fine.

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[usar17]

Sorry for such a delay on this. Been a busy winter.

So I have yet to swing thru autozone for a load test. And I have not done the voltage drop test from battery to starter.

But readings at the battery terminals

Truck off: 12.53V
Running: 14.14V
Cranking lowest read drop: 8.38V

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[Schurkey]

At minimum, battery is discharged. (I'm taking a wild guess that it's just plain defective.)

Slow-charge overnight, re-test. Disconnect charger, let battery sit for an hour.

A fully-charged battery should register 12.6--12.7 volts. When cranking, voltage shouldn't be under 9 V, more is better. Battery voltage does depend on temperature, if the battery is cold you'll have to warm it or compensate your voltage readings according to published volts-vs.-temp charts.

 

[HotWheelsBurban]

Most starter motors like to have at least 11 volts at the solenoid to work. Used to run into this back in the parts house days with blue oval owners. Fomoco spec is 10.5 volts minimum at the starter. They'd have bad solenoid, loose or bad connections and an undersized battery, and then wonder why it's having starting issues in July and August...in Houston.....
Fords were the first cars I saw with chronically undersized batteries. We used to say" Chrysler over engineers it, Ford under engineers it, and the General gets it right the first time....usually. Except for fleet cars (civilian ones). Those are ordered to make a low bid price. So they're the cheapest light duty crap you can imagine. I knew one company that bought a big fleet of 77 Impalas. Air conditioning was too weak to handle Houston humidity. So they replaced them with 78 LeMans'. Undersized brakes, worn out prematurely by Houston traffic. So they replaced those with 79 Ford Fairmonts. 200 CID 6 bangers. Crap brakes and transmission. Underpowered as hell. I had one like that for a driver's ed car. Pucker inducing to get on the freeway.....
IIRC the last fleet thes people had was K cars.

 

[usar17]

At minimum, battery is discharged. (I'm taking a wild guess that it's just plain defective.)

Slow-charge overnight, re-test. Disconnect charger, let battery sit for an hour.

A fully-charged battery should register 12.6--12.7 volts. When cranking, voltage shouldn't be under 9 V, more is better. Battery voltage does depend on temperature, if the battery is cold you'll have to warm it or compensate your voltage readings according to published volts-vs.-temp charts.

Well it's been in the 30s here [emoji28]

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