Battery power (voltage) level drops below level to crank engine

billr

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Grounding the meter at the battery is perfect. I think you already checked for voltage drop from battery to engine, correct?

I finally peeked at pictures of that starter, I see your difficulty in getting to those nuts/studs on the solenoid!

Alligator clips usually have sharp teeth and a grip strong enough to bite through rust, I don't think that is an issue. One trick is to wiggle the clip around once it is biting, to help the teeth scrub through any surface corrosion/paint.

Want another test? Clip the meter leads to each of those nuts on the solenoid. You should have 12V until you try to crank and the solenoid "clunks", then voltage (between the nuts) should drop to near-zero as the contactor inside closes.

How adventuresome are you? I think it is almost certain that solenoid is bad, and solenoids alone may not be available. Worse yet, that seems to be a pricey starter! You could open up the solenoid (take off that end cap) and see if the studs can be removed and rotated 180 degrees to make it "like new".
 

JackC

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It has been my limited experience ( only 2 starters) that those contacts inside those Toyota Starter solenoids are very easy to rotate and do solve the problem. The starters themselves seem to last forever and look like new when opened up.
 

billr

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Ah, there you go. I think Jack has confirmed that you can save $100!
 

josiah

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Billr, Jackc,Grcauto,

billr,
Wednesday 8/17 after reading your #46 reply above I did more tests; for tests the multi-meter black test probe was attached to battery negative terminal.

1) battery voltage=12.38. last time fully charged was 8/10. Left negative cable disconnect while car was inactive.

2) voltage between battery negative terminal and engine block
before turning ignition key=0
after turning ignition key=in a split second I get a number, but then it is gone and I see 0.

3) voltage at big cable nut (which connects battery cable to the battery clamp)
before turning ignition key=12.24
after turning ignition key=.13. And I heard a CLICK.

4) voltage at starter solenoid nut (located below the smaller wire)
before turning ignition key=2.20 to 2.24
after turning ignition key=.15

5) voltage at starter solenoid strap nut
before turning ignition key=0
after turning ignition key=hear is where it got interesting. When I turned the key to my surprise (shock) the engine cranked and STARTED. It started so quickly honestly did not hear the crank. I ran around to engine compartment to disconnect my test extension. And I let engine run for a few minutes.
I tuned off engine, reattached test extension to starter solenoid strap nut, turned key and engine started AGAIN for SECOND TIME, and it started immediately.
I tried 2 more times to get volt reading at strap and engine started EACH time, for THIRD and FOURTH time. By the fourth try I had regained my composure; because the first times it started I was so surprised that I forgot to take a volt reading. Anyway after turning key the volts jump to 10+ and quickly drops to zero.


If any of my volt readings above look questionable please let me know.

billr and JackC I appreciate the information about resetting the contacts in the starter solenoid . I have a repair manual which has instructions on how to repair a starter. I will check it to see if it has instructions for moving the contacts. Thanks for trying save me a few dollars.

Please let me know what I need to do next.

thanks, joe
 

billr

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Let's try this one more way. Connect the meter between the solenoid nut for the big cable and the positive battery terminal; get right onto the lead battery post, not just the cable clamp/terminal.

You should have 0V there, whether cranking or not. If you try to crank, and it will not, but that voltage jumps up toward 12V, then there is no doubt that the big cable is bad. Maybe the copper conductors, maybe the terminals at either end, maybe how well the terminals make contact with the starter stud or battery post; but something about that single big wire from battery to starter!

What you posted in 3) above is nearly conclusive, but we would need a simultaneous reading of battery voltage when the "big nut" voltage dropped to 0.13V Reading voltage from battery + to big nut does the same thing without needing two voltmeters.
 

josiah

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Billr,
8/20 clamped black test probe (using an extension) to starter/solenoid nut (the nut just below the plastic connector). And I tried to clamp red test probe (using extension) to positive battery post but could not because post too wide; so instead I wired extension clip to top of post.
voltage readings: before I turned ignition key=0.
After I turned key=at first for a split second I saw a number, but afterwards quickly to zero. So I tried again.
Important-> above I turned key twice and the engine CRANKED AND STARTED both times. Counting today and my previous tests on 8/17 that’s 6 cranks and starts in a row.

if you have additional tests please send to me.
i really want target the problem. And fix it.

could it be corrosion around solenoid nuts?

I appreciate your patience.

thanks, joe
 

billr

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If it cranks, no testing will show meaningful results. You have to catch it "in the act", when it has a hard failure. I doubt the nuts will be corroded in the contact area, where it matters, but you could simply loosen and retighten them. That would scrub away corrosion in the contact area. I still think the most likely cause is a bad cable, in that first inch or two next to the battery terminal. You could "whittle away" the insulation there for inspection, then recover the copper with several layers of electrical tape.
 

josiah

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Billr, JackC, Grcauto and MobileDan

Billr,
I loosen and tightened the two solenoid nuts; neither looked badly corroded.
I pulled back a small bit of covering (about half inch) and checked the positive battery cable which consists of 5 wires (or cables):
1) largest one is black+ red
2), another large wire slightly smaller is black
3) medium sized wire is white+black,
4) small wire is solid green
5) small wire is white+red
i noticed the largest wire (black+red), apparently goes directly to the starter solenoid

Replacing the cable wires doesn’t look like an easy job because (1) protective conduit apparently has to be removed and (2) I cannot determine how the wires connect at the fuse box above the battery.
before I attempt this job I will need to be confident that doing so will solve the problem. And I will need good instructions. I have a Toyota Motor Corporation manual but I did not find any instructions on replacing the cables.

After reviewing my repair manual I have more questions:
1) Can a starter seize-up due to inactivity? Previously, the car was inactive while I was dealing with brake light problems occurring on two occasions consecutively During this time I rarely started the car because I couldn’t drive it due to the brake light problems.
i noticed during this current problem the engine either doesn’t crank or it cranks and starts immediately. So can inactivity partially seize a starter?
2) If the large starter/solenoid wire (black and red) shorted wouldn’t it more likely that the engine would NEVER crank until the wire was replaced? This engine cranks sometimes; lately it has cranked and started 6 times in a row. I just don't know when it will revert back to NO crank.
3) Before the large solenoid wire shorted wouldn't a fuse blow instead? And based on my limited view of that wire it looks thick. I would think it would take a lot of abuse to short it.

8/26 update: Today engine cranked and started immediately. After reattaching negative cable. That is 7 cranks and starts in a row.

I plan to see if it will continue to crank and start at least every week.

Thanks, Joe
 

billr

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I'm suspecting that large BLK/RED cable is open at times, not shorted to anything. If I have been understanding your symptoms correctly, there are several that no kind of starter failure could cause. It is pretty much down to just that cable, if I am reading your posts correctly.

Now that it is "healed" there is little you can do except throw parts at it "just in case" If you do want to eliminate any chance of that big cable being open, just add another one in parallel to it. Leave it and all the other wires in place. You can probably scab on another cable lug at the starter end with little trouble, but connecting at the battery end will probably take some ingenuity. There are a variety of replacement battery-post clamps available at you FLAPS. I have even used simple hose clamps to secure two big cable lugs together.

There is usually no fuse in the power circuit to the starter.
 

josiah

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Billr,
i appreciate your reply.
1) in my previous reply I used the word “short”, which I thought applied to a broken cable or wire. apparently I used the wrong word. Going forward I will try to use words I understand.
2) above you said that the cable is perhaps open at times. I cannot understand how a cable can be open sometimes?
3) so the starter should be ok?
4) if, or more likely when, the engine stops cranking, what do think of my thought of using a jumper cable or an extension from battery to starter? If it cranks this should confirm that it’s the big cable? please reply when you are done laughing.

Thanks, joe
 

billr

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Billr,
i appreciate your reply.
1) in my previous reply I used the word “short”, which I thought applied to a broken cable or wire. apparently I used the wrong word. Going forward I will try to use words I understand. Generally, an electrical "short circuit" is when current can flow to someplace unintended. A common example would be when a wire rubs against the car frame enough that the insulation is worm through and current from the wire goes into the frame; sometimes causing the wire to burn up or a fuse to blow.
2) above you said that the cable is perhaps open at times. I cannot understand how a cable can be open sometimes? Intermittent "opens" in insulated are actually fairly common. The insulation, usually plastic, is somewhat elastic. When the copper conductors break, either from being tugged on to hard or flexed too much, the insulation tends to pull the broken ends of the conductor back so they are touching and make contact. Often, this contact isn't terribly good, but the next time the circuit is energized the poor-contact area heats up enough to spot-weld itself back together and make satisfactory contact. Of course, this "weld-healed" section of wire is not as robust as the original wire which broke in the first place. Eventually, the butted/welded wire ends are pulled part again and you have another intermittent "open". Any battery acid getting into the fine copper wires on a battery cable thins the wires, makes them weak, and easily leads to them breaking. Even if only a few strands get eaten away, the cable begins to flex more in just that one area and can soon break the other un-eaten strands from mechanical tension/flexing.
3) so the starter should be ok? I still think it is likely to be OK.
4) if, or more likely when, the engine stops cranking, what do think of my thought of using a jumper cable or an extension from battery to starter? If it cranks this should confirm that it’s the big cable? please reply when you are done laughing. I'm not laughing at all. That is an excellent trouble-shooting suggestion and you mentioning it saved me a lot of writing. Use a heavy cable, though, like the jumper. Or, put a few smaller wires in parallel. Four AWG 10 wires in parallel might be a lot easier to work with that the jumper and its big clips.

Thanks, joe
 

grcauto

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Billr,
i appreciate your reply.
1) in my previous reply I used the word “short”, which I thought applied to a broken cable or wire. apparently I used the wrong word. Going forward I will try to use words I understand.
2) above you said that the cable is perhaps open at times. I cannot understand how a cable can be open sometimes?
3) so the starter should be ok?
4) if, or more likely when, the engine stops cranking, what do think of my thought of using a jumper cable or an extension from battery to starter? If it cranks this should confirm that it’s the big cable? please reply when you are done laughing.

Thanks, joe
Based on your very limited knowledge of electrical systems you might want to consider a local shop.
 

josiah

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grcauto, thanks for reply. I have limited knowledge about auto electrical systems but I am learning. For example, previous problems with this car were confusing but with each one in the end I learned something I didn’t know before. I really want to solve and fix this. At least now I have a better understanding of a short. Also I feel that a shop will simply throw parts at me.

billr, update: the engine is cranking and starting good now. And has done good lately. I appreciate your advice.

thanks, joe
 
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billr

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On 8/26 you reported that it had magically "healed". You have changed nothing since then, correct?
 

josiah

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Billr,
No, I have not changed anything. This morning it cranked and started immediately. Drove it around the corner. That‘s 8 times in a row. Only precaution taken is I leave negative cable disconnected during inactivity.
thanks, joe
 
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