Starting issue 1991 4runner 3VZE automatic
 

Hey all, long time reader, first time poster, so I know this has come up time and time again, but I have the old "click no start" going on. Frequently, it will do that for a while, but always starts eventually. Sometimes it takes 3 or 4 turns of the key, sometimes it takes over a hundred. Sometimes it starts first try. I've replaced the starter twice, the first time seemed to resolve the issue for a few months, then it would get progressively worse so I replaced it again, which helped not at all. I've checked all my relays, but as near as I can tell, 91 3vze autos don't have a starter relay. Park/neutral position switch is working, it won't click when in anything but park or neutral. Checked voltage at the copper post on the starter, got a solid 12v, same at the smaller wire that I believe powers the solenoid. I can hear the circuit opening relay working by the passenger side kick panel, and the fuel pump in the back as well. I got to thinking bad ground, but doesn't the starter ground directly to the block just by virtue of being bolted to it? Anyway, it's a huge pain in my ass, especially when I'm in a rush or running late (which seems to be when it's at it's worst lol) I am now leaning towards a wiring problem, but don't really know where to start tracing it back. Any and all responses are appreciated.

Merry Christmas!
Nothing was wrong with your Toyota starters. The wiring is the problem - FROM THE FACTORY.
Correct.
See what applies to yours and see how to fix it here:
https://www.yotatech.com/forums/f199...l#post52368224

If you don't have a starter relay or it's wired incorrectly both the ignition switch and the park neutral safety switch are exposed to high current flows which lead to failure to start. This is covered in detail frequently...

There are two issues here. Firstly measuring a good battery voltage on the starter trigger wire doesn't mean anything if the circuit isn't drawing current. Imagine a garden hose with a spray nozzle and guage. The nozzle is closed and you have X psi, the nozzle is open you have Y psi. In this case psi is equivalent to voltage. How fast each nozzle setting fills a bucket on your roof you've aimed equates to current flow (amp).. IE if you don't have enough voltage/psi it's not going to fill the bucket.. Kind of a flawed analogy, but I think it explains it in term most people can follow..

So with the trigger wire connected and the voltmeter connected does the voltage drop when the key is turned. ... It should drop a bit indicating there is current flow.

...
Start at the battery negative terminal, make sure it is clean and tight. Follow the heavy guage wire to the block, it should be securely fastened and clean bright metal to metal on.the engine block. The next interface as you said is the starter housing to the block, the head side of the bolts are a good place to clean as they do not effect the starters orientation to the flywheel/flexplate.

If all of these are clean and tight and you still have issues you can do inline voltage drop tests.. Negative probe on battery, positive probe on each test point. The test points are each side of a junction or wire end to wire end. A good result is zero, a bad result is OL (open lead) or any substantial voltage.

Keep in mind you must have current flow across the circuit to do drop tests.

Add starter relay
 

RAD4Runner,
I will be putting together a starter relay for it tomorrow as outlined in your simplified description of that procedure. I would like to add the kill switch you mentioned, where would that be wired in? The power source lead with a switch running to the cabin? Luckily, I work part time at the local auto parts store and can put this together on my lunch. Should have it installed in the next few days and will let you know how it goes! Thanks for the help, I've read many of your write-ups over the last few years.

Added starter relay
 

Hey there. We'll, I added the starter relay as planned, but didn't go for the kill switch. It solved my problem, for about three weeks, then it went back to intermittently "click no start". I dealt with it because it wasn't as bad as before, but today my transmission started acting up, damn near zero power from a dead stop, but once it manages to get out of first gear it seems ok, and reverse still works just fine. Anyway, while I was draining the old ATF (which was very brown and burnt) I took a look at the relay I had added to the starter solenoid, and the contacts were pretty corroded, and I could hear what sounded like electric crackling coming from the area of the charcoal filter canister (near where I mounted the new relay). I cleaned it up with a small wire brush and sprayed some CRC electronic parts cleaner on it and it's been firing right up. However, the corrosion makes me think there is a faulty ground somewhere. What do you all think?

Tnx for good description of what u see.
What relay are using that you're able to access.contacts?
You sure u see corrosion and not burnt contacts from arcing?
Just as poor connection in starter solenoid coil circuit wud cause solenoid plunger to not actuate all the way to tightly close its contacts, the added starter relay may not be getting full power to its coil because of voltage drops in ignition switch, in neutral safety switch and wires in between.
If relay coil does not get full power, contacts will not close completely, cause high resistance and.overheating. If contacts are barely closing, and separating, that.wud.cause arcing that will also burn contacts. Arcing wud cause crackling sound.
Please measure voltage across relay coil (pins 86 and 85) while ign sw is in START position. Disconnect spade connector from starter solenoid so starter does not crank and u can take ur time measuring.
Inspect, clean and test resistance of ur neutral safety sw.

It's corrosion, I'm pretty sure. Greenish rust. The contacts are the ones that go from the wiring harness to the relay

By contacts, u mean connector pins, not relay contacts? How did u make the connections to the relay?
A picture paints a thousand words.

I'm having trouble uploading the pictures. I can select them from my files, but when I hit upload they disappear

:(
Yeah, Yotatech photo.upload has been acting up lately , even from computer.