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Old 03-17-2014, 11:15 PM   #1
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Default Starting woes - near my wit's end

I have a '93 L.E. that I bought new. It's been upgraded over the years, culminating in the big build. Lest these woes be placed on FM's shoulders, I should note that symptoms had started appearing some years beforehand.

Specifically, the car would have a no-start situation, usually when hot (but not always). Putting it in gear and bumping it slightly would often (but not always) allow it to start. Thinking that it was a faulty starter solenoid, I had FM replace the starter motor when the build was done. Unfortunately, the symptoms persisted, although they reared their head only sporadically and it was somewhat manageable.

Over the last few years, the problem has been getting progressively worse. Just in case, I changed the starter yet again, but there was no improvement. Thinking it might be a worn out ignition switch, I disassembled it and gave it a thorough cleaning. When that didn't work, I changed it out for a brand new, dealer-sourced unit. No change. I checked the ignition wiring and one of the main leads looked a little the worse for wear (it had an alarm system spliced in near the beginning of the car's life) and I cut and spliced in a new section of wire.

Symptoms were getting worse and worse. I replaced the battery with an upgraded AGM unit, to no avail. I added a zero gauge ground strap from the starter to the chassis - no change. Someone suggested that it might be because the main power lead was faulty, so I pulled the old line out and ran a brand-new 4 gauge (IIRC) wire directly from the battery to the starter motor (no intermediate connections whatsoever). No change. I had my new battery load tested and it checked out fine.

I parked my car early last fall because it is now essentially undriveable. When cold, it usually starts immediately and with vigour. When hot, nothing. Even bumping in gear doesn't seem to "fix" it anymore. Spring is now in the offing and I'd really like to be able to use my chariot again. Does anybody have any ideas of what to try next? I'm really at my wit's end.
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Old 03-18-2014, 04:34 AM   #2
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No start as in the start motor doesn't even turn?
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Old 03-18-2014, 12:12 PM   #3
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Sorry, I should have been more clear. If the starter turns over, the engine will catch right away, so it's not a CAS, spark or fueling issue. In my case, the starter won't turn over (you can hear the solenoid click, but three replaced starters indicate that it's highly unlikely to be a faulty solenoid and/or starter).
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Old 03-18-2014, 12:24 PM   #4
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This is common in the Celica AllTrac and 1st gen MX6 Turbo world.

Basically the solenoid signal wire (5v on the celicas, not sure what the volt is on the Mazdas) goes bad and won't pass the signal/power properly.

By bumping the car, you're probably just shifting something just right.

We usually did a solenoid wire bypass relay setup of some sort. Been a long time since i've messed with it, but the black 88 MX6 that i'm working on currently had this same exact issue. Previous owner was an AllTrac guy and did the relay "fix" on it. No more problems.



That said.... when i last "rebuilt" the car and built a whole new power and grounding system for it, i took a gamble and removed the relay system. Haven't had a problem cranking it yet.

What did this teach you? Probably not much. But hey, it's something.

(The relay thing is cheap and quick to do. Worth a short.)
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Old 03-18-2014, 12:34 PM   #5
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Sub'd.

I have this issue on mine too. And on a Kubota tractor. What's really confusing is you can clearly hear the starter solenoid "click," yet nothing. When it happens, repetitive turning of the ignition key and/or depressing of the clutch will get the starter to engage and, when it does, it engages strongly. Have new starter, new battery, new clutch switch, new ignition switch and freshly cleaned terminals on old wiring that ohms out with low resistance. It sounds like Steven has gone even further.

Ben, care to draw up a circuit showing what you are talking about with the bypass?
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Old 03-18-2014, 12:43 PM   #6
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You don't want a diagram i wrote.

Luckily this is pretty simple.

Quote:
Okay, I totally forgot to take pictures, so we're going blind. Sorry. I'll try to be as descriptive as possible.

You'll need a basic 30 amp four-pole 12v relay. A five pole can be used as well, you just won't use the extra load connection.

You'll only need to tap one wire on the car, the STR line from the ignition. This is the wire that trips the solenoid when you turn the key. The easiest place to get at this wire is from where it connects to the starter solenoid. It is the smallest wire attached to the starter, and the only one with a plastic plug-in connector. I can't say for certain on an All-Trac, but Toyota generally makes this wire black.

Basically, what you'll do is cut that wire, then connect each end to a different part of the relay.

The relay posts will be labled. Post 85 is ground. Post 86 is the power from the switch. Post 87 is constant 12v. Post 30 is the load(there are two load posts on a five-pole).

So, the wiring is as follows:
Post 85= Chasis ground or battery negative post.
Post 86= Ignition switch end of the STR wire.
Post 87= Battery positive post.
Post 30= Starter end of STR wire.

So what's happening?
Older Toyota's are nortorious for having a little wiring issue in the STR line. What happens is over time the wire gets brittle and resistance builds up inside. This results in the classic single "click" noise as you turn the key to the STR position. Power gets to the solenoid and trips it, and the starter gear kicks out. However, there isn't enough amperage to keep the solenoid energized, and the gear retracts before it can spin.

So what we've done is boost power to the solenoid. The relay takes much less power to trip, so it can be activated by the wires that couldn't get enough power to the solenoid. When the relay is tripped, it routes 30amps to the solenoid, and it energizes without a hitch.

Don't know if that's exactly what you were looking for, but I hope it helps!

And now some links:

Car not starting randomly? READ THIS (30 Amp Starter Relay Mod) - Page 3

4th Gen Starter Problems
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Old 03-18-2014, 12:50 PM   #7
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I think I'll try it.
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Old 03-18-2014, 12:56 PM   #8
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Me too. Thanks Concealer.
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Old 03-18-2014, 01:04 PM   #9
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This makes a lot of sense actually, i bet this fixes your problems. It's just like when you have a low battery and you try to start your car and the starter just clicks, except in this case you have a full battery and it's an old corroded wire that isn't giving enough voltage.

+propz concealer
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Old 05-19-2014, 12:35 AM   #10
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Default FIXED!

I thought I'd update everyone who contributed to this thread. I took a long time to get to this point because the weather has been really crappy here this Spring and I really only got the car on the road about ten days ago.

Based on the advice from Concealer above, I installed a relay in-line with my ignition circuit and starter solenoid, just in case the wiring was getting cranky (or not cranky, depending upon your point of view) when hot. I did a beautiful job with the wiring - using heat-shrink tubing and all the accoutrements. Result: Same as before, started when cold and not when hot.

The type of non-start was different than before, however. At times, the starter would turn the engine over a quarter turn and then quit. At other times, it would click and do nothing. So, it was back to first principles - doing voltage-drop testing. When "not starting", battery voltage would drop to between 8 and 9 volts. When starting, it dropped hardly at all (approx. 12.5V all the way), so didn't think it was a battery issue. I switched ends and checked the voltage drop across the two big terminals on the starter. Result: Non-start saw the voltage drop to zero, which pointed to a faulty solenoid.

Now wait a cotton-picking minute! This is a new/rebuilt starter from Mazda parts. This would make the third or fourth faulty starter in a row. All I could think to do was to remove the current starter and replace it with one of the previous units (I had a hunch). BINGO! The car started strongly the first time. I took it for an extended drive to get it nice 'n hot, came home and, with some trepidation, turned the key again. RRRRR-Vroom! Tried it again, with the same result. Let it heat soak for ten minutes and it started right up.

Here's what I think happened: I had cascading failures. The wiring (whether the hot lead from the battery, the ground and/or the ignition circuit) had issues, which caused my slowly-deteriorating initial issues. Last Spring I replaced the starter again, experienced the same symptoms and started rewiring everything (as described above). This fixed the initial issue but now I had a faulty starter solenoid causing a near-identical problem. Replacing this unit with the old starter (which, it turns out, was good), made everything right with the world.

Thanks to everyone for their help. I'm glad to have my beastie back. Fingers crossed that this fixes the problem once and for all.
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Old 05-19-2014, 10:37 AM   #11
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props for updating your thread with your fix. now someone will find this and get the answer they need!
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