06 Tacoma Starter Spins But Doesnt catch HUGE UPDATE!!!!! I have another update....

Chill Jim, no way would I put a non Denso starter on the truck, that’s the whole reason I am replacing the contacts. I appreciated your reply, and I didn’t mean to sound rude, Perhaps I am blunt or its the fact nuances don’t come thru the keyboard? I just wanted to let you know as for the copper contacts you can get good quality rebuild kits for much cheaper, in case you need them again. I type like a hillbilly but that said we are guys no need to be tempermental. Again thanks for replying

 

It's all good, I would just be concerned about anything from ebay. I also never use rebuilt starters or alternators that I didn't do myself or from a Known reputable shop.

 

I stopped today and spoke with the mechanic working on my son's truck. I hope i say this all correctly. The low voltage is in increments 6 , then 3 then 6 and then fully 12. It doesnt grind because it happens very quickly. So quick that his meter can barely see the voltage changing. I think I understand that the Bendix does throw out far enough to touch the teeth on the flywheel during the low voltages, but not far enough to engage, until the right voltage is reached. Then it catches the flywheel and starts. So i still think the long term issue is that eventually, the flywheel teeth will grind down. He said anything can be fixed with enough time, but they are clueless as to why this is happening.

 

Sorry if this was mentioned but is this voltage fluctuation on the little wire from the ignition switch or the big cable from the battery?

If its happening on the little wire I'd suspect a worn ignition switch.

If it's happening on the cable from the battery I'd look at the battery and all the big connections

 

Let it be known, I’m not an electrical guy by any means.
But could one disconnect the solenoid wire and try to “start” the truck, while measuring voltage?
If it still drop with the solenoid disconnected. Then start working back towards the battery.

Again, I can not see how you are getting partial gear/flywheel engagemen.
But stranger things have happened?

 

@TnShooter I was thinking something similar - connect a remote starter switch (see Innova 3630) from battery to solenoid to see if it engages fully.

 

Yeah, I think some else mentioned this before.
It is my understanding this doesn’t happen all the time.
And when it does, it grinds with the flywheel.
I figure maybe check the solenoid wire for low voltage.
That way we don’t risk damaging the flywheel, during testing for low voltage before the solenoid.

 

Key switch has been mentioned more than once.

Also the starter relay. Most relays have 4 pins. If you have a multimeter and a pair of jumper wires, its easy to test. Most relays are normally open. With the meter set to ohms, you'll probe the relay pins til you find 2 showing resistance, those 2 you'll later being attaching to 12v. The other 2, again on ohms, you'll be testing for how good the connection inside the relay is. Hopefully your jumper wires have small alligator clips. Connect the jumpers to the battery leaving the one end going to battery positive off the battery. Then connect the meter, set to ohms, to the other 2 pins. Touch the jumper to battery positive, you should see very little resistance on the meter, .7 ohms or lower is good. Repeatedly touch and untouch to battery positive. Im willing to bet you'll see high resistance intermittently. BEFORE you remove the relay, keep in mind, they crack very easily, even with relay pliers. I like to use a L shaped pick, with the battery disconnected, cram it under the relay, gently pry up while rocking and pulling it out. Sometimes they're held in with a bolt through the pins, or a tab that has to be fanagled out of the way. Once you get it out, testing it is easier than it sounds as long as your alligator clips are small enough to not touch each other.

If the relay tests good, I'm betting on a bad key switch. If someone has a wiring diagram to be able to test it without having to remove it that would be ideal. If not, getting it out just to test it could be quite the chore.

I had a machine today, had me stumped. The factory said to check all grounds, which i did. Then found the key switch to have 40-230 ohms of resistance. Replaced it, all problems disappeared (main relay and injector was chattering). This is on a machine that the key switch is known to constantly fail.

If forced to guess, I'd say your key switch is bad. But the relay is easier to access so I'd check it first.

L shaped pick, it doesn't need to be this exact same one, but the L shaped end is what to look for.

Ullman Devices No.1810 Double Pointed Scriber, 9-1/4" Long

 

This and I'm done:

 

Looking at the schematic jimmyh posted; the only thing between the key switch and the solenoid is a relay.
I'd pull the solenoid and swap it out with another then check voltages again.
Pull the wire off the solenoid when checking voltages.

 

I'm with a few of the others. Make sure the truck is in park, or neutral, won't roll or run you over etc... jump the solenoid directly (key to "ON") Doesn't start? Then work backwards.

Take the keyswitch out of the equation entirely. Test the relay, it's super easy even with minimal amount of electrical knowledge.

 

If the starter is whining after the engine starts, it is drawing power from somewhere else. A sticking relay or bad diode can cause this. Could also just be a bad ground or connection at the ignition switch.

 

I'd replace that start relay if it was me

 

Jimmyh, old guys do rule!

I'm not ane electrician but I can read and use my finger to follow a line. Looks like the starter relay (STA Relay) will have a wire green with black stripe (G-B). With the relay removed, battery positive and negative disconnected, meter set to ohms, connect to battery positive cable & the green wire black stripe. You could stick a spade connector in the relay hole for this test. Repeatedly turn the key to start position checking to see what the meter says. I would really test that key switch. Turn it normally, hard, pull up, push down, wiggle. I'm guessing you'll see low resistance (good), and high resistance (bad). I don't know what 6 EB1 is, maybe a connector. This along with testing the relay should at least eliminate those 2 as a problem.

Something to help save the new flywheel from being chewed up during all this testing is to remove the starter, set it on the ground, connect it with jumper cables and a jumper wire for the solenoid. Its going to jump and twist so keep that in mind.

 

Or just disconnect that big old fat battery cable ( Black with Red Stripe ) that drives the motor. That way the solenoid can do its thing without turning the starter motor.

** Of course you would make sure that the cable end doesn't touch a ground. Wrap it in electrical tape... or shove it into a leather / rubber glove and tie it up.

 

If the voltage to the starter is varying quickly then you would need a more specialized meter to read the voltage going to the solenoid. Something like a scope-meter. It will show the variations that last only a few milliseconds when the key is turned. A well equipped electrical shop should have one of these.

My guess so far would be the starter relay in the relay box. Easy to test or change but don't overlook the relay socket in the box having bad terminals or wire connections.

 

I have switched the starter relay with others in the box and no difference.

 

Sounds like you are going to need to figure out where the low voltage is occurring.
I’d start at the starter and work backwards towards the battery.

 

Where is the mechanic measuring/finding the voltage loss? At the little control wire on the solenoid?

 

This is a head scratcher. I hope this is resolved down the road and we can all say ahhhh, told ya so.

Being an electrician and studying the schematic again I see other possibilities. First, if the voltage to the solenoid varies randomly, there is a possibility that the starter relay is chattering-that is opening and closing rapidly due to a poor energizing signal. This would show up as a low or rapidly changing voltage at the solenoid terminal intermittently. The starter relay appears to be energized from the ECU probably based on whether the park switch is closed, etc. The signal from the ECU to close the starter relay would be a constant 12 volts. If the signal from the ECU is intermittent, the starter relay will chatter and the voltage at the solenoid will not be sufficient enough to fully engage the solenoid. This means that the control path from the ECU should also be checked. The easiest way is to monitor the signal at the starter relay coil. Or to eliminate the signal from the ECU, pull the starter relay and jumper the terminals where the relay contacts plug in.

Hope this makes sense.....