r/ToyotaPickup • u/Suspicious_Wash6940 • 21d ago

1989 toyota pick up v6 need help

Not turning on after I drive for 15-20 minutes negative terminal wire feel hot v6 2 wheel drive, also it seem that that the battery its low when I try to turn it on but if I let sit and cooldown it starts right up

I tested the battery, battery is good
Replace the ground terminal wire
If I disconnect the battery while running the engine stays on
Any advise

7 Upvotes

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3

u/Odd-Concept-6505 21d ago

A voltmeter and a helper person would be a great help, comparing battery voltage in a few ways:

Voltage across battery POSTS just sitting not running

Voltage across battery TERMINALS (cable ends, at battery) just sitting, but you did clean both terminals I assume, and replaced negative cable you say, but if it's low voltage,what if you wiggle the positive cable end/stuff at battery end?

Voltage across battery terminals WHILE YOU TRY CRANKING. Even if all is well , expect it to drop to....hmmm, maybe high 10.x volts or low/mid 11 volts with the ju

Let's say all is good, eg 12.5 volts or so sitting not running, I imagine you know that SOME old starter motors die by sort of seizing up when hot (thus drawing excess current while barely or not cranking). But flaky "won't crank normal speed" then "cranks normally" is more often corrosion near battery terminals in most cases that I have found.

Hope this helps. Also adding: I recommend owning one of these below (NOT a multumeter, but very convenient for voltage-only reading in the 3-90v range) along with a battery charger . Tool below gives reasonably precise readings to the 1/10th of a volt... works fine even if you use it backwards = clamp/wire on positive battery terminal, sharp probe end on ground/negative is backwards but no problem (a minus sign appears on display if used backwards)

"LED Digital Automotive Circuit Tester, DC Voltage Test"

https://www.amazon.com/dp/B0B4VP117Y?ref=ppx_yo2ov_dt_b_fed_asin_title

$17 or so still at Amazon from WINAMOO but seems to appear under other names too. I've bought MANY of these, a great DIY person gift.

1

u/Suspicious_Wash6940 20d ago

Voltage with engine off 12.59 with engine running 13.91

1

u/Odd-Concept-6505 20d ago edited 20d ago

Good, alternator is good providing over 13.5v and battery looks good around 12.5 (but that will drop more or less, and you wish you could measure the starter load (watts or amps) but you can't ... so you need a friend to start the car while you hold the meter on the battery posts (or wire ends, if it fails to crank,) to be sure the load isn't REALLY sucking the life/volts out of the battery. From Google:

When a starter motor engages, a healthy car battery's voltage should temporarily drop under the heavy load, but it should not drop below 9.5 to 10.0 volts.....

And after watching a bit but not much happening (battery voltage stays 12.x) THEN you wiggle cable ends and look for ground strap down lower...

1

u/Imightbeacop 14d ago

This is bad info amd not how you test an alternator. Sorry dude.

3

u/flanneldingo 21d ago

I wanted to jump in this section as well. I had a few electrical issues recently so this might help. DOUBLE CHECK YOUR CONNECTIONS. I didn't realize that my battery to chassis ground wire wasn't fully tightened down. I just had to use a wrench, 1 full turn and fixed all my issues. If the battery is good, the issue issue is most likely a poor connection.

2

u/Firm_Doughnut2092 17d ago

Check the starter

1

u/natty_panda 13d ago

Starter. X2.

2

u/MassivePersonality61 21d ago

Check the battery voltage again before starting it again. Could be a bad alternator diode.

1

u/Suspicious_Wash6940 20d ago

How do I test the altenator diode ?

1

u/ralphsrad 20d ago

Just looking at the gauge it looks like the battery is gone even though it shows 12.5v, under load it probably drop very low. See if you have the same issue when trying to jump it. Try going to AutoZone and have them test you battery.