73 FJ40 Won’t Start

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Try to jump over the ignition switch and run a jumper cable from the battery 12V positive terminal to the starter solenoid. This will isolate the ignition/key system as being the problem. Your jumper wire acts as the key circuit in this scenario.
 
Okay, I figured something out but I'm not exactly sure what it's telling me yet. If I run a wire directly from the positive terminal on the battery to the small wire on the starter with the connection point, not the big bolted wire the motor does turn over. So what is the problem
 
A clicking noise when attempting to start typically indicates a dead/weak battery. Have you tried to jump start it? or have you tested it with a different battery?
A weak battery can still run all your lights and signals without having the amps required to turn the starter.
Yes I tried jumping it. No luck and it's sitting at around 13.6 volts now.
 
There is a starter solenoid relay mounted on the firewall above my battery. Dad, when I turn the switch to start the vehicle, the 12 volts going to this relay attached to the firewall then gives 12 volts to the other side of the relay which Powers the small connector at the starter. I jumped a wire going directly from the positive of the battery to the terminal that did not have the power on the relay on the firewall and it turned over. So I think that starter solenoid relay mounted to the firewall is bad. I'm going to replace it tonight to verify. Not sure who installed this or why it's wired like this but this is how I got it from South America. So who knows as I just found this part at AutoZone which is made for hot rods.

Anyone tell me how it is supposed to be wired up or is this normal cuz it does not seem normal. Seems like a South American homemade fix.
 
So if you try and short across the relay, does it turn over?

You need a good feed to the solenoid to get it to flip fully across, especially if it's tired, so any resistance in a connector or switch terminals or bent wire will cause a problem.
Look for melted wires and connectors. Anything that's getting hot is your problem. Check your fuse and fusible link contacts and connectors.
The relay was probably added to move the load away from the ign switch. Not a bad idea so long as its spec'd for the job .
 
So if you try and short across the relay, does it turn over?

You need a good feed to the solenoid to get it to flip fully across, especially if it's tired, so any resistance in a connector or switch terminals or bent wire will cause a problem.
Look for melted wires and connectors. Anything that's getting hot is your problem. Check your fuse and fusible link contacts and connectors.
The relay was probably added to move the load away from the ign switch. Not a bad idea so long as its spec'd for the job .
I replaced the relay same problem there. I jumped from one side of the starterlay solenoid attached to the firewall to the other side terminal and it did turn over. Did not click like it's been doing. Randy, wire directly from the battery to the small wire on the starter turns over, not clicking. Checked resistance and continuity of wires going from relay to battery relay to starter. All good. 13. Volts at battery at one side of the relay and at the starter.

Problem still clicking no starting. Any ideas what I can check next? I don't see anything burned or kinked anywhere. I'm missing something somewhere simple. I know it.
 
So if you try and short across the relay, does it turn over?

You need a good feed to the solenoid to get it to flip fully across, especially if it's tired, so any resistance in a connector or switch terminals or bent wire will cause a problem.
Look for melted wires and connectors. Anything that's getting hot is your problem. Check your fuse and fusible link contacts and connectors.
The relay was probably added to move the load away from the ign switch. Not a bad idea so long as its spec'd for the job .
What relay and fusible link are you talking about that? I should check, do you have any pictures or any way of explaining on where they may be at and how I can check them? Thank you very much
 
I meant the aftermarket relay (presumably added by a PO).
The fusible link is the slightly thinner wire online with the main feed from the battery (if you have one). It acts as a slow blow fuse to protect everything.

Don't test using the "continuity" setting - this is the cause of 90% of the electrical misdiagnosis on here. Its misleading because it can have a wide tolerance to resistance. Use the lowest resistance setting instead (sorry it doesn't go beep though).
Direct wires in good condition should read well below one ohm. Maybe even zero on your meter. A poor connection may have only a few ohms across it when cold, but try and dump 10A through it and it will shoot up and cause your problem.

Measuring volts is also not helping you here - with zero current flowing through a poor connection, you won't see a voltage drop - you'd only see a reduction when it's active. If you can test volts while attempting to crank then that may be useful though.
You already know that you can acheive some sort of connection, otherwise it wouldn't click.
Have you cleaned the ignition switch connector? Try bypassing each segment in turn.
 
@Nolacajun75
Hello everyone, I noticed the old thread but hopefully someone can help me out. I have a 81 FJ43 with the 2f engine. Last week it was running perfect. I know the carburetor is perfect because Jim c. Rebuilt it. The battery seems good but don't know how to check for a load. It all the sudden will not start. It does not turn over it just clicks. Figured it had to be the starter or the starter solenoid. So I put a brand new starter in and still the same exact problem. It started to happen sometime and then more and more and then now it just won't start at all over a couple week.. everything else on the vehicle works when I turn the vehicle on the radio lights. Everything works fine but when I try to start it it just clicks like a bad starter. There any wire I should be checking or any fuse I can look at? I can't figure this out. It's driving me crazy. Thanks everyone. I appreciate the help. It runs fine if I push start it so I know it's running good just not starting good.

My battery is less than 6 months old so I doubt it's bad but it may. It is sitting at around 13.6 volts in my garage with nothing on and it did go up to 14.4 with the alternator running when I checked it a couple weeks ago. Battery terminals are all clean and connected tightly. All battery cables have been replaced with large gauge wire, and has been fine for the last 2 years until now and I don't see any melted wires anywhere.
You hijacked a thread entitled "73 FJ40 won't start" and you have a 81 FJ43.

The result is you're getting advice from circa 1973 owners and the 1981 folks skip over the thread. Circa 73's don't have starter solenoids "on the firewall". All the US market 2F engines I've been acquainted with have the starter solenoid integrated with the starter motor.

You mention using a jump wire to the little wire connection next to the big wire on the starter. That's the solenoid integral to the starter motor.

So, it possible the solenoid on the firewall is an anti theft device? You said you bought in from a dealer. What's the ten digit part number?

You really need to institute the " one picture is worth a thousand words" advisory.
 
I meant the aftermarket relay (presumably added by a PO).
The fusible link is the slightly thinner wire online with the main feed from the battery (if you have one). It acts as a slow blow fuse to protect everything.

Don't test using the "continuity" setting - this is the cause of 90% of the electrical misdiagnosis on here. Its misleading because it can have a wide tolerance to resistance. Use the lowest resistance setting instead (sorry it doesn't go beep though).
Direct wires in good condition should read well below one ohm. Maybe even zero on your meter. A poor connection may have only a few ohms across it when cold, but try and dump 10A through it and it will shoot up and cause your problem.

Measuring volts is also not helping you here - with zero current flowing through a poor connection, you won't see a voltage drop - you'd only see a reduction when it's active. If you can test volts while attempting to crank then that may be useful though.
You already know that you can acheive some sort of connection, otherwise it wouldn't click.
Have you cleaned the ignition switch connector? Try bypassing each segment in turn.
Thanks for the information. I appreciate it. The fusible link you're talking about where is it? You said it's the main feed from the battery but to what? Where does it go to?

I pulled steering column apart and the dash out. I cleaned the connections on the ignition switch plug and I checked continuity for The wire going to the relay to excite it and it was good if I run a jumper from the positive terminal of the battery to the spot on the ignition switch that goes do they relay and it turns over fine if I just turn the key it clicks

I know I need to check the fusible link but I'm still not sure where it is. This is driving me crazy
 
The Black with white wire on the ignition switch goes directly to the input that excites the relay to open it. The black with yellow stripe wire on the ignition switch connects to the black with white stripe wire on the ignition switch when the key is turned to the start position.

I thought that if I put 12 volts direct to the black with yellow wire when I turn the switch to start it would feed the black with white wire, the 12 volts to the relay and start but it did nothing. Just click click. If I run that same direct 12 volt from the battery to the black with white stripe wire on the ignition switch, it turns over like it should

Hopefully this helps narrow it down. I'm lost right now. So I'm not sure and I am confused on what actually feeds this switch the 12 volts. That's where my problem is.


1000003137.jpg
 
The Black with white wire on the ignition switch goes directly to the input that excites the relay to open it. The black with yellow stripe wire on the ignition switch connects to the black with white stripe wire on the ignition switch when the key is turned to the start position.

I thought that if I put 12 volts direct to the black with yellow wire when I turn the switch to start it would feed the black with white wire, the 12 volts to the relay and start but it did nothing. Just click click. If I run that same direct 12 volt from the battery to the black with white stripe wire on the ignition switch, it turns over like it should

Hopefully this helps narrow it down. I'm lost right now. So I'm not sure and I am confused on what actually feeds this switch the 12 volts. That's where my problem is.


View attachment 3662989
Okay referencing the picture above. There is 12 volts always sitting on the yellow and black wire. There is no voltage on any other point. If I run direct line from the positive of the battery to the bottom point of the ignition switch the black with red line wire. Everything turns on like I'm in accessory mode like my radio and stuff comes on and then when I turn a key to start it starts up like normal. Can someone help me out? I'm getting there. I'm so close.
 
@Nolacajun75

You hijacked a thread entitled "73 FJ40 won't start" and you have a 81 FJ43.

The result is you're getting advice from circa 1973 owners and the 1981 folks skip over the thread. Circa 73's don't have starter solenoids "on the firewall". All the US market 2F engines I've been acquainted with have the starter solenoid integrated with the starter motor.

You mention using a jump wire to the little wire connection next to the big wire on the starter. That's the solenoid integral to the starter motor.

So, it possible the solenoid on the firewall is an anti theft device? You said you bought in from a dealer. What's the ten digit part number?

You really need to institute the " one picture is worth a thousand words" advisory.
Yeah I know I hijacked the wrong thread probably but you know how it goes. Hope I didn't disappoint you. Anyone else here but seem like some good information. I don't know how it could be an anti-theft device.

Here are some pictures

PXL_20240625_164239260.jpg


PXL_20240625_164245070.jpg
 
Since you have a constant 12V at the Black/Yellow wire at the ignition switch, and your engine will turn over fine when you manually apply 12V to the starter solenoid that is integrated in the starter itself. It sounds to me like you may have a faulty ignition switch.

The ignition switch/key simply takes the 12V from the Black/Yellow wire and applies it to the accessory wire Black/Red wire first and then to the starter solenoid wire.

You know your starter works, you know your accessories work and you know that you have power at the ignition switch/key like you should. The missing link, so to speak, is the key/ignition switch.

Thats my $0.02
 
Since you have a constant 12V at the Black/Yellow wire at the ignition switch, and your engine will turn over fine when you manually apply 12V to the starter solenoid that is integrated in the starter itself. It sounds to me like you may have a faulty ignition switch.

The ignition switch/key simply takes the 12V from the Black/Yellow wire and applies it to the accessory wire Black/Red wire first and then to the starter solenoid wire.

You know your starter works, you know your accessories work and you know that you have power at the ignition switch/key like you should. The missing link, so to speak, is the key/ignition switch.

Thats my $0.02
My rig is a 1977, so my advise is wholly based on my experience with that rig. Not sure what that relay/solenoid is on your firewall.
 
Since you have a constant 12V at the Black/Yellow wire at the ignition switch, and your engine will turn over fine when you manually apply 12V to the starter solenoid that is integrated in the starter itself. It sounds to me like you may have a faulty ignition switch.

The ignition switch/key simply takes the 12V from the Black/Yellow wire and applies it to the accessory wire Black/Red wire first and then to the starter solenoid wire.

You know your starter works, you know your accessories work and you know that you have power at the ignition switch/key like you should. The missing link, so to speak, is the key/ignition switch.

Thats my $0.02
This is the second ignition switch. I tried installing both brand new from Toyota, part number 84450-60070. Is this the wrong part number I'm using. I could buy another one but this will be the third one I put in that is new. What do you think
 
Definitely sounds like the ignition switch, but is it possible that the wires got mixed up?
Disconnect the switch, and check continuity at each position.
Turn it to the start position and measure the contact resistance
 
Definitely sounds like the ignition switch, but is it possible that the wires got mixed up?
Disconnect the switch, and check continuity at each position.
Turn it to the start position and measure the contact resistance
Okay so I used my multimeter to see what the internals of the ignition switch are doing and I am not sure what it is supposed to do so I'm not sure if it is right or wrong.
With these key key in lock position, the black wire with white stripe checks for continuity and is measured at 96 ohms the black wire with red stripe to the yellow wire with blue stripe or to the red wire with black stripe beeps continuity only for a second but not staying beeping and measures 31 ohms. With the key position in ACC position, everything is exactly the same as above in the lock position. With the key in the on position, all wires check to each other is touching and continuity. The black wire with white stripe to each wire checks good but sits at 68 ohms on each. All other wires to each other. Check good but are at 2 ohms with the key and the start position. The blue wire with red stripe wire to all others is open all other wires to each other. Check good for continuity and are sitting at less than .1 ohm.

I'm not sure what this is telling me if my ignition switch is good or bad but this the second brand new switch I got from Toyota. I did verify it is the right part number I think but should I be buying the aftermarket versions? Maybe the stock one does not work?

Also, my Hanes manual wiring diagram is different than the actual wires coming out of the ignition switch color wise.
 

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