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Post by deegore on Nov 22, 2015 20:11:17 GMT -5
Finally got some ice and snow to try out the 4x4 and i got nothing. My 89 carbed justy does not engage. The dash lights do not come on. When I push the button, I can hear a click from under the hood or below the car. Any advice what to look at would be appreciated.
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Post by certimafied on Nov 23, 2015 16:14:00 GMT -5
If you are absolutely sure about 4wd not engaging I would start by checking fuses my book ,for an 88, says fuse number 1 not sure about your car.
Next locate the vacuum switching valves on the firewall, thats where they are on my car yours may differ, Make sure the vacuum switching valves are actually switching and opening as they should. If no activation can be felt be sure they are getting signals through the wires, if no signal I would go after switch assuming fuse is ok if signal present and no activation I would think the valve is bad. If they are activating and opening as they should...
Then make sure the vacuum hoses going to and from them are ok no cracks or splits. check the vacuum hoses at the transmission for cracks as well.
If all that checks out, get a hand vacuum pump and put on one of the sides of the actuator on the transmission see if it holds vacuum if not there is a problem with the diaphragm. Hope that helps and doesnt create any confusion Im not the best at explaining. Good luck!
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Post by deegore on Nov 26, 2015 18:25:28 GMT -5
Thanks man, that helps allot. It looks like the hoses were switched around coming out of the vacuum switching valve. When I switched them and pushed the button, the 4x4 came on. The problem is it will not turn off. I can turn off the 4x4 by disconnecting the 2wd hose and sucking on it. Does this point to a bad switching valve or is it possibly a wiring problem?
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Post by deegore on Nov 28, 2015 2:36:36 GMT -5
Did some testing today and found it's definitely the vacuum switching valve. There are four wires going to the valves (two to each valve). Looking at the plug the way I have it sitting, the top two terminals are always hot when the car is on. The 4x4 button switches the ground between the bottom two terminals. The vacuum switching valves are n.c. (normally closed). My vacuum switch on the left is not opening so I'm gonna try to repair or replace it.
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Post by certimafied on Nov 28, 2015 2:45:28 GMT -5
Sorry just got back on the boards today, glad to hear you figured things out though...
I hope you can get that valve working, they can be pricey to replace but are typically pretty easily available.
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Post by deegore on Dec 5, 2015 9:57:50 GMT -5
Those are spendy, over a hundred bucks most places I looked. I ended up getting one off a toyota in the junk yard for $5. it does not bolt on, but it works just fine. Thanks for the help.
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Post by certimafied on Dec 8, 2015 8:55:05 GMT -5
Sweet glad you got it. I'm kind of dreading the day I have to replace mine, they look like they have been repaired before.
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Post by parker on Jan 16, 2017 10:42:20 GMT -5
So my 4x4 isn't working either, and I can hear the switch clicking but nothing happening. I switched the two hoses as it seems like they could get mixed up. When I turned the car on I saw the 4 green wheels light up but I couldn't do anything to turn them off. They turned on without me pressing the button and would not turn off no matter what.
So, I was able to find a switch at a junkyard (the justy was literally in the very back corner of the big lot) and I threw it in my car with the hoses how they were before switching them. Same as with my original switch, I can hear clicking but nothing engaging. So I'm thinking the issue might not be the switch but something to do with the vacuum lines?
I'm a decent mechanic but fairly new when it comes to vacuum and electrical. All help/suggestions/walkthroughs are very much appreciated. Thanks!
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Post by deegore on Jan 16, 2017 13:48:29 GMT -5
The vacuum line comes from the manifold and splits into the solenoids. There should always be vacuum here when the car is running. One of the solenoids should always have vacuum going thru it when the car is running. You can test this by removing the hoses from the solenoids that go to the transmission and feeling for vacuum with your finger. Be careful removing the hoses because the barbs break off for literally no reason. When you press the 4wd button the other solenoid should have vacuum. If they both seem to be working, see if you can engage/disengage 4wd by sucking or using a hand vacuum pump on one of the hoses that go to the transmission. You can also test the solenoids by applying 12 volts and see if they open. Without power one side of the solenoid should be sealed.
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Post by papcina on Mar 11, 2021 7:19:18 GMT -5
I've got a similar issue, so I'm using this thread to ask a suggestion... my carbed 91 Justy won't engage 4WD when button pressed... but insted, if the button remains pressed, after some time during driving it engages itself in 4WD... and then the same issue when trying to disengage 4WD, I press the button to turn off 4WD but it remains in 4WD, and after some time, even few days it unblocks from 4WD mode randomly...
what could be the first step I should check?
The fuse I doub't its broken if it engages randomly...
thanks
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Post by deegore on Mar 11, 2021 9:39:21 GMT -5
Maybe a vacuum leak? I would start by checking the idle vacuum. It should be around 19inHG. A vacuum pump could tell you how much vacuum it takes to engage/disengage the 4wd. Maybe the diaphragm in the transmission is leaking or stiff. It you don't have a pump, it should be fairly easy to switch the 4wd by sucking on the vacuum hoses that go to the transmission. Check that the vacuum is switching between the hoses when you push the button so you know it's not a bad electrical connection.
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Post by papcina on Jun 25, 2023 4:46:46 GMT -5
Hi everyone!
Ok, i have some issues with my 4wd but seems like i found the error.... fortunately i have 2 same Justys (1992 carb) so i swapped the vacuum switch valve to see if it is working properly... and it is... It seems there is no power on the connector so there is some wire broken somewhere at the 4wd engagement... i checked the fuse box-it is ok (even though i dont know which one should be for 4wd engagement), i took out the 4wd button on the gear handle, there is no voltage on any wire (3 of them), i guess there should be some voltage on the button wires too? So, seems like there is some wire broken somewhere... can someone help me to diagnose what to look for of the wiring? Is it somehow possible to directly rewire the 4wd button and vacuum switch to a 12v source?
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