FZJ80 starting woes

LARGEONE

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True. But please refer to my comment about being an “electrical midget”. Likely won’t be me who figures it out. :)
 

Hulk

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For those of you following the thread, it's clear the issue is somewhere in the ignition circuit on my 80. I do want to track this down and fix it, but I'd also like to drive my 80 this summer. So to the certain horror of @Rzeppa and @DaveInDenver, I have installed a starter button that activates a relay, sending strong power to the solenoid so it starts every time. If you push the button with no key in the ignition, it will crank but not start. Insert the key, turn to the right, hit the button, and my 80 starts like a champ.

Once I figure out what's wrong and fix it, I can tear all this out easily. But now my 80 will start again. Not being able to wheel in the summer was a bummer.

FYI: found the perfect push button switch (ECH STB6035) at Napa which fit the existing hole for the manual throttle cable, so no cutting required.

IMG_2378.jpeg
 

DaveInDenver

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For those of you following the thread, it's clear the issue is somewhere in the ignition circuit on my 80. I do want to track this down and fix it, but I'd also like to drive my 80 this summer. So to the certain horror of @Rzeppa and @DaveInDenver, I have installed a starter button that activates a relay, sending strong power to the solenoid so it starts every time. If you push the button with no key in the ignition, it will crank but not start. Insert the key, turn to the right, hit the button, and my 80 starts like a champ.
Horror, LOL. You know you just became a "WTF previous owner did this?" Welcome to the club, refreshments on the table.

I've said before. They're just tools, get it working, have fun, fix what's broken when it breaks. I'm not sure what you've done that you need to still turn the key but that sounds like you didn't fully bypass the latent issue. But then again I'm OCD would want to know (1) what failed and (b) what I actually did that fixed it.
 
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HDavis

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This sounds like a classic case of leaking magic smoke. You are doomed for certain.
 

DaveInDenver

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some creative rope routing and you could have your pull cord come right out the same spot as the start button. :p
And here I'm thinking "Yeah, that's cool, but why not just pop start it like we've always done?" Then I remembered some people foolishly optioned automatics in mini trucks for some unknown reason.
 

RayRay27

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Out with the old and in with the new! Thanks @DanielChase for loaning me (permanently) a new Denso starter. Had a starting issues last week. Nic @Stuckinthe80s and Chase were able to convince me it was the starter. Second time in 4 or 5 years.
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RayRay27

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So while I have the starter out I was going to check the same transmission connector that Romer pointed Matt to check. I have an A442 transmission and everything is on the driver side.

These 4 connections are above the starter. Now I know the two round ones are for the NSS but I wasn't sure what the other two are for. Does anyone else know? I am trying to trace them back but am having difficulty because they run across the top of the tranny.

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RayRay27

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I know this may not be my issue or it may not have anything to do with it but I went ahead and replaced my NSS too.
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Inukshuk

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Today for the first time since replacing my ignition switch my 80 took three turns of the key to start. This was after getting home from the mountains, so it was hot, and I parked, moved the 100, then went to start and park the 80. Doh!
 

DomOfTheDead

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For those of you following the thread, it's clear the issue is somewhere in the ignition circuit on my 80. I do want to track this down and fix it, but I'd also like to drive my 80 this summer. So to the certain horror of @Rzeppa and @DaveInDenver, I have installed a starter button that activates a relay, sending strong power to the solenoid so it starts every time. If you push the button with no key in the ignition, it will crank but not start. Insert the key, turn to the right, hit the button, and my 80 starts like a champ.

Once I figure out what's wrong and fix it, I can tear all this out easily. But now my 80 will start again. Not being able to wheel in the summer was a bummer.

FYI: found the perfect push button switch (ECH STB6035) at Napa which fit the existing hole for the manual throttle cable, so no cutting required.

View attachment 96276
Hey Matt, can you give anymore details on how you set this up? Did you install a separate relay just for this or did you just run a New 12v lead to this switch?
I am having intermittent starting issues on my 80 and I am having trouble finding the source. Brand new battery 2 weeks ago, new alternator brushes and remanufactured denso starter earlier this year and recently began having issues with random no start. I like the idea of having this push button starter engagement.
 

LARGEONE

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Basically Matt did what I've been planning to do, except I was thinking of running a strong hot from the battery to the starter relay, that is actuated by the current small starter relay wire. So, basically the current system which has obviously lost some juice, is used to "turn on" another "hotter" circuit straight from the batter to the starter relay. For some reason it seems to take more juice to actuate the relay on the starter, than it does to actuate the relay on the small 30amp aftermarket relays. Or, maybe it's just that the wires are old and reducing the current to the starter relay?

Dave...school me. Basically what Matt did but with everything kicked on by the starter key.
 

DaveInDenver

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@LARGEONE, it's all about that current. But also resistance and voltage... The stock system has developed additional resistance somewhere, which as it goes up causes current or voltage to go down. It's the law (Ohm's) and must be obeyed whether we like it or not.

Make sure I understand what you're asking. You want to keep the dash key switch and all the wiring from the battery to the solenoid coil, at which point you tap it to control a stand-alone solenoid?

You'd only be bypassing maybe 1/4rd of the circuit so hopefully it's the part where the issue is.

The stock circuit already has a pretty "hot" circuit to the starter, which is a fusible link -> heavy battery cable -> solenoid contacts -> starter motor -> engine block (ground).

The engine block then has a heavy cable to the battery to complete the circuit.

In Matt's case this didn't appear to be an issue. Replacing the battery cables didn't fix it initially anyway.

The issues seem to have developed in the control circuit, which goes battery -> fuse block -> harness -> dash key -> harness -> neutral switch -> harness -> solenoid coil -> engine block (ground).

More places for stuff to happen.

What Matt did was bypass a bunch of things that might be causing high resistance and thus low current or excessive voltage drop. If you get sufficient voltage (thus lack of resistance to the current) to still trigger a second solenoid coil then the problem seems most likely to be the starter grounding to the engine block.

Starting System_Operation.png
 

LARGEONE

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Thanks Dave.

I put in a new battery, got rid of my 2nd battery system (at least removed connection and with the full battery starts every time. It’s when the battery is not fresh that it has issues. AGM bats have not lasted more than 3 years for me with my dual bat system.

I have gone to a huge NOCO jump pack instead of the dual battery. This jump pack started my 7.3 ford diesel the other day. So I think dual bat is out for me for a bit.
 

DomOfTheDead

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PS Zero issues since I put in a new battery in September 2021
This is initially what I thought was my issue as I was running an optima red top that I had to warranty earlier in the year. (The Optima brand isn't what they used to be and garbage now IMO) After the 2nd red top tested ok, I still replaced it with a wet cell interstate on Xmas Eve but when we tried to leave grandma's house that night, the voltage was below 12v and had to jump it to start. I suspect resistance issues causing a slight drain due to, as dave mentioned, bad grounding, wire sizing, old connections, ect. I am well versed in the various points of electrical degradation as a licenced electrician and years of car audio but truth be told, I loath troubleshooting automotive electrical gremlins and would rather bypass OEM wiring and run new stuff for piece of mind. Thus, I like the idea of a starter button and was wondering how this was achieved. Also the interweb tells me these trucks don't have a typical relay for the starter and that everything is tied to the ignition key barrel.
 

Inukshuk

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Also the interweb tells me these trucks don't have a typical relay for the starter and that everything is tied to the ignition key barrel.
Correct. That ingition key switch at the end of the "barrel" is beefy! PS it is also basically removable, cleanable, replaceable. I did not disassemble the new one so I can's say how much wear mince had. Amazing this stuff still works 28 years later
 

RayRay27

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Just saw this video on YouTube where you can buy a blade type 1 amp diode that will allow your charging voltage to increase for your AGM batteries.

He put a link in the description where to buy the diodes.
 
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