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IMO this battery terminal needs to be replaced and the wires cleaned up. However a friend says this is fine and he's run like this for years. Having problems similar to a bad alternator, but wanted to see if fixing this wire might help before I buy an alt.
Whos rig? If yours then always fix or replace questionable wiring. If its his make him buy you a 12 pack when you have to pick him up because he has an electrical problem that's suddenly not fine anymore. Also test your alternator. I think many people rebuild them now because the quality of after market parts has gone downhill. Blindly throwing money at a truck to "repair" non properly diagnosed problems is a bad way to try and fix something.
Last edited by thefishguy77; Nov 20, 2018 at 09:36 AM.
Whos rig? If yours then always fix or replace questionable wiring. If its his make him buy you a 12 pack when you have to pick him up because he has an electrical problem that's suddenly not fine anymore.
Haha, well it's my rig. 1988 Runner 3vz-e. I am going to try and salvage the wires and get new terminals. That absolutely looks like it could be causing problems, so I was a bit shocked to hear him say it was "fine".
Do you have any recommendations on testing the alt?
I got a reading of 12.8V from the positive and negative terminals of the battery while the car was running (about 15 minutes after a jump start and revving the engine).
When it idles it sounds like it's about to die, but when I rev, the RPMs go up no problem.
Last edited by gilesitis; Nov 20, 2018 at 09:41 AM.
With the engine running, the lights, fans, radio and anything else you can turn on. Trace the negative cable there to the engine block, put a positive lead from a volt meter to a nice new scratch in the bolt head. Now put your meters negative probe directly on the battery post. This is a loaded circuit voltage drop. 0.05 is really bad 0.10 is completely in acceptable. Unacceptable.
This style of battery connector is meant to get you home where you can put a proper cable back on it.
You got how much of that cable actually in the clamp, looks like less than a quarter of it.
Last edited by Co_94_PU; Nov 20, 2018 at 02:06 PM.
So just to make sure I understand,
Place the positive MM lead on a new scratch on the negative battery terminal and place the positive MM lead on the negative battery post?
No on the second part. Negative MM lead to neg batt post.
Looks like testing the voltage drop from alt to batt. Think of the MM hookup like a parallel train track going from alt going back to the batt. It would give a value previously advised. Careful not to get caught in moving parts.
Def fix the wiring. Hopefully just that and not the alt itself.
You could also test the alt directly for voltage from its positive terminal to any metal part of the alt housing. Pos lead and neg lead respectively. Should get above 13-14v. If still 12, its not generating like it should.
I think he meant UN-acceptable. Smartphone typing isnt exactly a smart science sometimes.
Last edited by 75w90mantraN; Nov 20, 2018 at 12:27 PM.
No on the second part. Negative MM lead to neg batt post.
Looks like testing the voltage drop from alt to batt. Think of the MM hookup like a parallel train track going from alt going back to the batt. It would give a value previously advised. Careful not to get caught in moving parts.
Def fix the wiring. Hopefully just that and not the alt itself.
You could also test the alt directly for voltage from its positive terminal to any metal part of the alt housing. Pos lead and neg lead respectively. Should get above 13-14v. If still 12, its not generating like it should.
Oh sorry, that was a typo, I meant to say negative!
Have you ever removed an alt from a 3VZE engine? It looks straightforward, but im trying to figure out if I can get away with not removing the distributor cap.
Not on that engine. It really depends on how well you can contort your arms and how well a grip or torque you can generate with little room. Removing the cap if it makes it easier is a little step. But removing it is doable with basic hand tools and a bit of safety in mind.
I realize removing the dist. cap won't be much of an issue and it will give more room.
Once I get the clearance, I will run that alt check as you recommended.
But first I will tackle the wiring. Do you guys have any recommendations on terminals? Considering the current ones are some kind of cheap temporary terminals...
So just to make sure I understand,
Place the positive MM lead on a new scratch on the negative battery terminal and place the positive MM lead on the negative battery post?
negative on negative post. Positive on the block mounting point at the other end of the wire.
If you swap the MM lead's you will get a negative voltage, just drop the negative off and its the same. So really either way will work, as long as you are aware of it.
Voltage measurements are always "the voltage potential between point a and point b".
The terminals actually look fairly ok. Just the exposed copper strands need to be re-fitted into the terminal clamp-down bolts. From what I could see in the photo.
Few ways to insulate, heat shrink, electrical tape, plastic flex tubing.
All in all, clean and tight is the principle.
To clarify, testing the alt is done with the dist cap on. Should reach the pos terminal/bolt with a test lead. Right Toyota?
12.8V charging voltage is to low. Should be from 13.5 to 15.1Volts. See "How Charging System Works" thread.
Like mentioned above, I would replace that with properly crimped battery cables and a good battery terminal. I recommend the robust "Marine" terminal (LIKE THIS).
Do not remove your alternator. Do the suggested checks first. Pls see signature.
A picture paints a thousand words ...
Multi-meter in Volts DC setting, One meter lead to bare shiny metal (i.e., scratched) of bolt head pictured below, and other multi-meter probe to bare, shiny metal (i.e., scratched) of negative battery terminal. That will check if you have excessive voltage drop on the battery negative cable-terminal-battery post interface.
12.8V charging voltage is to low. Should be from 13.5 to 15.1Volts. See "How Charging System Works" thread.
Like mentioned above, I would replace that with properly crimped battery cables and a good battery terminal. I recommend the robust "Marine" terminal (LIKE THIS).
Do not remove your alternator. Do the suggested checks first. Pls see signature.
A picture paints a thousand words ...
Multi-meter in Volts DC setting, One meter lead to bare shiny metal (i.e., scratched) of bolt head pictured below, and other multi-meter probe to bare, shiny metal (i.e., scratched) of negative battery terminal. That will check if you have excessive voltage drop on the battery negative cable-terminal-battery post interface.
This would be performed with the car running correct?
OOPS, on second thought... test that Co suggests above would not be very accurate because ground return for lights, horns, radios, etc go through the fender ground cable, not the engine bock ground.
Significant currents that go through the block ground and would produce measurable voltage drop across that cable are:
1) Starter motor cranking amps could be hundreds of amps, and
2) Starter solenoid coil current, approx 12 amps
And these need to be measured while cranking, so not perfectly safe.
Could also be just an academic task, and regardless of results you would still need to replace that worn out wiring.
IF, and only IF, I were to do it, I would:
1) Crimp ring terminals on battery cable,
2) Fill voids with good solder, probably using an 80-watt soldering iron OR blowtorch,
3) Insulate to resist battery acid/fumes.
4) Use marine battery terminals (which I have now).
OOPS, on second thought... test that Co suggests above would not be very accurate because ground return for lights, horns, radios, etc go through the fender ground cable, not the engine bock ground.
Significant currents that go through the block ground and would produce measurable voltage drop across that cable are:
1) Starter motor cranking amps could be hundreds of amps, and
2) Starter solenoid coil current, approx 12 amps
And these need to be measured while cranking, so not perfectly safe.
Could also be just an academic task, and regardless of results you would still need to replace that worn out wiring.
IF, and only IF, I were to do it, I would:
1) Crimp ring terminals on battery cable,
2) Fill voids with good solder, probably using an 80-watt soldering iron OR blowtorch,
3) Insulate to resist battery acid/fumes.
4) Use marine battery terminals (which I have now).
Update: I took off the old negative terminal, straighten out the exposed wire and tried to get as much as I could into the new terminal. This still left some of the copper exposed so I wrapped it in electrical tape.
Jumped off the vehicle and after a few minutes checked voltage at the battery; got about 13.8, so that’s an improvement from the other night at 12.8.
Reved the engine for a few more minutes and then drove around for about 10-15 minutes. Checked voltage again and it had dropped slightly to 13.4.
Continued to rev for a few more minutes but couldn’t get a reading higher than 13.42. However I noticed the poor idling improved and it doesn’t sound like it’s going to die.
I’m pleased to see the improvements but shouldn’t that reading be more than 13.4? Could it still be the alternator going bad?
I have not yet tested voltage directly at the alt but that’s probably my next step.
Im also going to go back out shortly and see if it fires up again.
Last edited by gilesitis; Nov 21, 2018 at 02:23 PM.
Reason: Typo
OOPS, on second thought... test that Co suggests above would not be very accurate because ground return for lights, horns, radios, etc go through the fender ground cable, not the engine bock ground.
..
The block ground serves as ground for the alternator. (On the R series this comes out of the alternator loom and is attachef near the PS mount, it will be similar on the V series but i cant give details) Still a valid point, I was on break and didn't get to mention to-do the same for the body ground wire that is bundled there also at the battery.
If you want to get real picky, I didn't bother to look up the resistance per foot or the size cable used to math out what the cable actually drops. Essentially you want as near zero in the connectors as you can get.
And I haven't been following the conversation if any of this was mentioned.
In fact if you have the head strap in place you have a noisy multipath ground, but that's another issue
Nov 20, 2018 | 09:17 AM
