- Thread starter
- #221
I removed the old plugs and installed a few set screws to clean this up. I used some thread sealant to help ensure coolant doesn't eventually find its out. Still need to find some plugs where the additional temp sensors reside.
Build Build: Rusty Pumpkin Project 74' FJ40
- Thread starter bdawg23
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I removed the old plugs and installed a few set screws to clean this up. I used some thread sealant to help ensure coolant doesn't eventually find its out. Still need to find some plugs where the additional temp sensors reside.
@bdawg23 watching with great interest. I would have tremendous frustrations so I admire your tenacity particularly …that mechanically, things can be worked out, measured, re-installed etc. What gets me is checking with the meter and finding a circuit problem, looking towards the schematic to trace it out…then re-checking with the meter and finding something different. Hats off to you for that drive and positive attitude.
I’d have spelled every curse word I know in 10 different ways and created new words from the remnants. One reason I don’t enjoy wiring. Funny that I have been an amateur radio guy for 46 yrs and built a lot of equipment yrs ago
Continue success on this “stuff”
I’d have spelled every curse word I know in 10 different ways and created new words from the remnants. One reason I don’t enjoy wiring. Funny that I have been an amateur radio guy for 46 yrs and built a lot of equipment yrs ago
Continue success on this “stuff”
- Thread starter
- #223
Thank you.
It’s not the journey not the destination right
But honestly if I was near a LC shop I’d probably have given in by now and dropped it off already.
- Thread starter
- #224
Ok, little update.
Recall problem was the coil was getting 12V regardless of Key position (off, acc, on).
First I pulled the switch and after checking it with a multimeter it was working as supposed to. No power to any leads when off, power to acc when in ACC, and power to black/yellow ignition wire when on, then also checked power when turned to "start" position. So switch is ruled out.
Next I removed the white/blue wire from the white wire connecting the ammeter. When I did this the coil lost power while the key was in the OFF position. BINGO. That means something downstream of the white/blue wire was giving the coil power when it shouldn't.
I think traced the white/blue wire back to the fuse block. There is a white/blue wire that comes into the fuse block from the alternator and a white/blue wire that comes into the fuse block from the ammeter. When I removed the white/blue wire coming from the ammeter to the fuse block I again lost 12v at the coil while the key was OFF.
I then turned the key ON and checked the coil, 12V. Now I'm trying to look at the wiring and see if the white/blue wire from the ammeter is in the wrong spot or if there is some other connection going on.
The previous owner also wired in a line directly from the alternator to the fuse block and had it connected to a blue/red wire, no idea what that was/is for yet.
Recall problem was the coil was getting 12V regardless of Key position (off, acc, on).
First I pulled the switch and after checking it with a multimeter it was working as supposed to. No power to any leads when off, power to acc when in ACC, and power to black/yellow ignition wire when on, then also checked power when turned to "start" position. So switch is ruled out.
Next I removed the white/blue wire from the white wire connecting the ammeter. When I did this the coil lost power while the key was in the OFF position. BINGO. That means something downstream of the white/blue wire was giving the coil power when it shouldn't.
I think traced the white/blue wire back to the fuse block. There is a white/blue wire that comes into the fuse block from the alternator and a white/blue wire that comes into the fuse block from the ammeter. When I removed the white/blue wire coming from the ammeter to the fuse block I again lost 12v at the coil while the key was OFF.
I then turned the key ON and checked the coil, 12V. Now I'm trying to look at the wiring and see if the white/blue wire from the ammeter is in the wrong spot or if there is some other connection going on.
The previous owner also wired in a line directly from the alternator to the fuse block and had it connected to a blue/red wire, no idea what that was/is for yet.
- Thread starter
- #225
Quick little thing here that I forgot to post about installing my distributor. I had ordered a new dizzy clamp awhile back and finally installed it when I put my new dizzy in.
I think ordered a new dizzy to replace the one that wasn't working, and it came with a new dizzy clamp so I figured, sweet, I'll have a spare clamp.
I put them next to each other and they looked the same so I grabbed the first one I had on hand.
However, when I went to install the new dizzy (thank you @cruisermatt) I just couldn't get it to sit properly so I pulled the clamp and checked it. You can see in the pic below that the first clamp I had doesn't fit the new Toyota dizzy I received. Good reminder to check fitment as soon as I get a part even if I'm not going to use it right away.
So I grabbed the clamp that came with the new dizzy and it fits flush with the bottom (or is that the top?) of the dizzy. Such a small thing but makes a bit difference in fitment.
I think ordered a new dizzy to replace the one that wasn't working, and it came with a new dizzy clamp so I figured, sweet, I'll have a spare clamp.
I put them next to each other and they looked the same so I grabbed the first one I had on hand.
However, when I went to install the new dizzy (thank you @cruisermatt) I just couldn't get it to sit properly so I pulled the clamp and checked it. You can see in the pic below that the first clamp I had doesn't fit the new Toyota dizzy I received. Good reminder to check fitment as soon as I get a part even if I'm not going to use it right away.
So I grabbed the clamp that came with the new dizzy and it fits flush with the bottom (or is that the top?) of the dizzy. Such a small thing but makes a bit difference in fitment.
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I strive to always make sure my customers get what they really need 
I can vouch for that comment @cruisermatt … and while I’ve said it before….thanks
- Thread starter
- #228
Great news. Learning to follow the electrical diagram goes a long way and can save you time. Or you can do what I did and just pull the harness back out and strip it down so you can see and touch each wire 
In all seriousness though, I've been learning a ton but it's a lot of extra work. To recap my issue here is what was going on:
- with key OFF I had power to dizzy/coil and all accessories
- I thought maybe it was a bad switch, or a shorted wire somewhere
- actual cause was the blue/white wire from the ammeter was plugged into the wrong spot on the fuse box
I did do a good job of hooking it back up the way I found it but I'm 99% sure the PO had this wrong. This wire when the battery is connected was providing power to extra circuits on the fuse panel when it should have been hooked up to the headlights (opposite side red wire).
Once I moved the blue/white wire to the opposite side everything starting falling into place.
- I finally could hook up the ammeter without sparks flying
- I had power to coil/dizzy with the key in the ON position only
- I had a few circuits that were hot with key OFF go cold and only turn on with the key ON
So what does this mean? Well I'm starting to finally get the wiring dialed in to where it should be which should allow me to clean it up and put it all back with some more confidence. I actually found a few bad spots that I'm fixing (bare wire exposed) and I'm currently checking circuits now to make sure they work:
- temp sensor
- oil pressure sensor
- various grounds (light tester thing is amazing for this...can't remember who but someone here recommended it)
Going to try and make a video on all this at some point to try and explain it (as best as I can).
I also got the exhaust hooked up and found out the new 2F header pushed the exhaust back about 6 inches so the hangers don't line up any more. At least I've got it semi attached and should be enough to drive the truck to a local muffler shop. I ordered a three bolt adapter plate so the muffler shop has something to work from.
My reverse light switch in the tranny needs attention, tons of solder and old wires, and once that is cleaned up I'll feel better about putting the tranny cover on and bolting in the seats.
I also have a block heater in this motor which for the colder temps is amazing. I plugged it in last night and after a few hours the block was getting nice and warm. Super nice to work next to something putting off warm heat. Plus it brought the coolant temp up and I found a leak at the thermostat because I forgot to tighten it!
Anyway...progress
In all seriousness though, I've been learning a ton but it's a lot of extra work. To recap my issue here is what was going on:
- with key OFF I had power to dizzy/coil and all accessories
- I thought maybe it was a bad switch, or a shorted wire somewhere
- actual cause was the blue/white wire from the ammeter was plugged into the wrong spot on the fuse box
I did do a good job of hooking it back up the way I found it but I'm 99% sure the PO had this wrong. This wire when the battery is connected was providing power to extra circuits on the fuse panel when it should have been hooked up to the headlights (opposite side red wire).
Once I moved the blue/white wire to the opposite side everything starting falling into place.
- I finally could hook up the ammeter without sparks flying
- I had power to coil/dizzy with the key in the ON position only
- I had a few circuits that were hot with key OFF go cold and only turn on with the key ON
So what does this mean? Well I'm starting to finally get the wiring dialed in to where it should be which should allow me to clean it up and put it all back with some more confidence. I actually found a few bad spots that I'm fixing (bare wire exposed) and I'm currently checking circuits now to make sure they work:
- temp sensor
- oil pressure sensor
- various grounds (light tester thing is amazing for this...can't remember who but someone here recommended it)
Going to try and make a video on all this at some point to try and explain it (as best as I can).
I also got the exhaust hooked up and found out the new 2F header pushed the exhaust back about 6 inches so the hangers don't line up any more. At least I've got it semi attached and should be enough to drive the truck to a local muffler shop. I ordered a three bolt adapter plate so the muffler shop has something to work from.
My reverse light switch in the tranny needs attention, tons of solder and old wires, and once that is cleaned up I'll feel better about putting the tranny cover on and bolting in the seats.
I also have a block heater in this motor which for the colder temps is amazing. I plugged it in last night and after a few hours the block was getting nice and warm. Super nice to work next to something putting off warm heat. Plus it brought the coolant temp up and I found a leak at the thermostat because I forgot to tighten it!
Anyway...progress
I know you are no stranger to “ a lot of extra work “
Nice to see forward movement so to speak. I maintain wiring is a weakness of mine to a point beyond basics. Hats off to you
Nice to see forward movement so to speak. I maintain wiring is a weakness of mine to a point beyond basics. Hats off to you
- Thread starter
- #230
Well I got the front harness reinstalled last night and went to plug in the white wire to provide power to the truck and got some serious sparking!! This is NOT what I expected since I had everything plugged in outside the truck and it was working fine.
When hooking up the white wire that runs to the ammeter to the battery sparks flew.
Previously had everything hooked up outside the truck with no sparks.
If anyone is in the market for an FJ40 project send me a DM. Will trade for older two stroke dirt bikes
This morning feeling somewhat better I decided to do some testing with my multimeter. Hoping someone will look at this and help see something or ask a question I haven't asked myself yet to keep the troubleshooting going.
First thing to check for is a poor ground. So I tested the grounds...
- Positive battery terminal to ground spot on frame 12.9v
- positive battery terminal to ground spot on frame from engine block 12.8v
Next I wanted to test for a short. Switched multimeter to continuity (ohms)
- I got .2 from white wire to battery ground (key off)
- I also included measurements with other wires below
Here is my fuse panel
Visual pics for reference
Testing phase
- I ran 4 test with various connections hooked up or removed
- all tests with KEY OFF
- multimeter set for resistance (ohms) with negative lead to engine ground, positive lead to each wire on fuse block
- the one circuit that showed variable resistance is the (black/yellow, blue/red, blue/red), group
- the white/blue and red circuit should have continuity b/c this circuit is an always on circuit (headlights) when removed Red goes to 1 confirming
Does this provoke any questions that I'm not asking? Any insights anyone might see looking at this?
One other thing I tried to test but was getting lost and needed to take a break was the gauge cluster.
- both wires to ammeter had continuity to ground
- ground wire on radial plug behind cluster had 6.6 ohms resistance which seemed high for a ground wire
Thanks in advance
When hooking up the white wire that runs to the ammeter to the battery sparks flew.
Previously had everything hooked up outside the truck with no sparks.
If anyone is in the market for an FJ40 project send me a DM. Will trade for older two stroke dirt bikes
This morning feeling somewhat better I decided to do some testing with my multimeter. Hoping someone will look at this and help see something or ask a question I haven't asked myself yet to keep the troubleshooting going.
First thing to check for is a poor ground. So I tested the grounds...
- Positive battery terminal to ground spot on frame 12.9v
- positive battery terminal to ground spot on frame from engine block 12.8v
Next I wanted to test for a short. Switched multimeter to continuity (ohms)
- I got .2 from white wire to battery ground (key off)
- I also included measurements with other wires below
Here is my fuse panel
| top left | top right |
| white/blue | red |
| black/yellow | black/yellow |
| black/yellow | blue/red |
| blue/red | blue/red |
| white/blue | blue |
| red/black | |
| green/red | |
| green/red |
Visual pics for reference
Testing phase
- I ran 4 test with various connections hooked up or removed
- all tests with KEY OFF
- multimeter set for resistance (ohms) with negative lead to engine ground, positive lead to each wire on fuse block
- the one circuit that showed variable resistance is the (black/yellow, blue/red, blue/red), group
- the white/blue and red circuit should have continuity b/c this circuit is an always on circuit (headlights) when removed Red goes to 1 confirming
Does this provoke any questions that I'm not asking? Any insights anyone might see looking at this?
One other thing I tried to test but was getting lost and needed to take a break was the gauge cluster.
- both wires to ammeter had continuity to ground
- ground wire on radial plug behind cluster had 6.6 ohms resistance which seemed high for a ground wire
Thanks in advance
- Thread starter
- #231
I disconnected the ammeter and everything seems to be working fine. I knew this to start just by trial and error but I was really hoping my work with the multimeter would prove what was going on so that next time something like this happened I could use the multimeter instead of guessing.
One issue I have now though is when I turn on the left turn signal my headlights flash on and off. Doesn't do this with the right turn signal. Weird...
I sat in the truck and the steering wheel was really close to me. If you look closely I somehow installed the column upside down lol
Thankfully it was a quick fix and I flipped the bracket around.
You might also notice I've got a place to sit! Installed the seat and gas tank cover last night along with the tranny cover. I had one issue with the shifter which I found a solution for from this post: FJ40 Won't Shift - https://forum.ih8mud.com/threads/fj40-wont-shift.814616/page-2
I used a screwdriver and put the 4 speed into neutral and then installed the shifter and was good to go.
photo credit: @Harald thank you!
I got the air cleaner assembly installed too (looks like I forgot to hook up the vacuum advance line...)
Not sure about this rubber boot thing though. It looks like I should have an air cleaner boot ring clamp from parts diagrams. However my air cleaner doesn't have a wing nut on the carb side, only the air cleaner side so I need to look into this more.
starting to feel like it might be time to start thinking about putting some gas in the tank!
One issue I have now though is when I turn on the left turn signal my headlights flash on and off. Doesn't do this with the right turn signal. Weird...
I sat in the truck and the steering wheel was really close to me. If you look closely I somehow installed the column upside down lol
Thankfully it was a quick fix and I flipped the bracket around.
You might also notice I've got a place to sit! Installed the seat and gas tank cover last night along with the tranny cover. I had one issue with the shifter which I found a solution for from this post: FJ40 Won't Shift - https://forum.ih8mud.com/threads/fj40-wont-shift.814616/page-2
I used a screwdriver and put the 4 speed into neutral and then installed the shifter and was good to go.
photo credit: @Harald thank you!
I got the air cleaner assembly installed too (looks like I forgot to hook up the vacuum advance line...)
Not sure about this rubber boot thing though. It looks like I should have an air cleaner boot ring clamp from parts diagrams. However my air cleaner doesn't have a wing nut on the carb side, only the air cleaner side so I need to look into this more.
starting to feel like it might be time to start thinking about putting some gas in the tank!
I have that air cleaner assembly. The PO put a rod in the Rochester carb and a wing nut on top after punching the hole. His opinion was every time he was working the rig on the trail, the joint would pop off when you needed filtration the most. I have never had it come loose since 82 when I got the rig.
- Thread starter
- #233
thanks for the feedback! sounds like I'll be fine
I've found when electrical stuff does weird stuff, it's usually a ground issue. Skimming thru your wiring setup test results you noted you had resistance thru the ammeter which seems odd to me. I've never put a meter on an ammeter, but I would think the ammeter should have not create any resistance. The Ammeter should only show current flow. Charge or discharge.
- Thread starter
- #235
good call out and since I've removed the ammeter and the system is working fine (mostly) I bet there is something here. thx!!
Love the Beta Trials!
- Thread starter
- #237
Miss that thing! Sold it to pay for the motor rebuild
- Thread starter
- #238
Well I had a friend over today to help me with troubleshooting my electrical stuff.
As you all know I removed the ammeter because it was giving me a spark when I tried to hook up the power to the truck. Here is what we did to try and diagnose this further:
- added ammeter back into the circuit with white wire to + and white/blue to negative on ammeter
- removed all fuses from fuse block
- we got sparks when hooking up the + battery
We then removed the negative side of the ammeter
- added power and got a spark
We then removed the positive side of the ammeter
- added power and the headlights turned on but no spark
We then removed the radial connection from back of instrument cluster
- added power and got a spark but no headlights
We then removed the ammeter from the housing and hooked it up
- added power and nothing happened
We then installed the ammeter in the cluster (but no housing)
- added power and nothing happened
we then installed the instrument cluster housing with the ammeter hooked up
- added power and got sparks
I think the housing/circuit board are not behaving very well together and something is shorted. That's when noticed the broken connection on the CB where I highlighted with the yellow square. Tried to do a quick repair with solder and it didn't work very well.
This location seems to coincide with the white/black ground from the radial plug. This ground connects all the lights and various other grounds on the dash from what I see.
I don't have any answers here but at least I found something else that doesn't seem to be proper. I think sourcing a new board is going to be the way to fix this. I'm def guilty of removing this cluster with the battery hooked up when I first got the truck so I'm not sure when I fried this, or maybe it was fried before I got it and I made it worse but either way could be the basis for some issues here.
Hope ever one had a nice thanksgiving !
As you all know I removed the ammeter because it was giving me a spark when I tried to hook up the power to the truck. Here is what we did to try and diagnose this further:
- added ammeter back into the circuit with white wire to + and white/blue to negative on ammeter
- removed all fuses from fuse block
- we got sparks when hooking up the + battery
We then removed the negative side of the ammeter
- added power and got a spark
We then removed the positive side of the ammeter
- added power and the headlights turned on but no spark
We then removed the radial connection from back of instrument cluster
- added power and got a spark but no headlights
We then removed the ammeter from the housing and hooked it up
- added power and nothing happened
We then installed the ammeter in the cluster (but no housing)
- added power and nothing happened
we then installed the instrument cluster housing with the ammeter hooked up
- added power and got sparks
I think the housing/circuit board are not behaving very well together and something is shorted. That's when noticed the broken connection on the CB where I highlighted with the yellow square. Tried to do a quick repair with solder and it didn't work very well.
This location seems to coincide with the white/black ground from the radial plug. This ground connects all the lights and various other grounds on the dash from what I see.
I don't have any answers here but at least I found something else that doesn't seem to be proper. I think sourcing a new board is going to be the way to fix this. I'm def guilty of removing this cluster with the battery hooked up when I first got the truck so I'm not sure when I fried this, or maybe it was fried before I got it and I made it worse but either way could be the basis for some issues here.
Hope ever one had a nice thanksgiving !
This is actually a good opportunity to improve the safety of your electrical system but would require additional work and if your not comfortable doing electrical it might not be for you.......
The wire that runs to your ammeter carries a lot of current and a short here can cause big issues. Rerouting the wires that go to and from the ammeter so they don't run through the cab is a good way to reduce the chance of cooking your harness. You can eliminating the ammeter entirely and eventually convert to a voltmeter if you like, this is a common upgrade for this portion of the wiring and I believe there's several threads on how to do it here on Mud if your up to the challenge.
The wire that runs to your ammeter carries a lot of current and a short here can cause big issues. Rerouting the wires that go to and from the ammeter so they don't run through the cab is a good way to reduce the chance of cooking your harness. You can eliminating the ammeter entirely and eventually convert to a voltmeter if you like, this is a common upgrade for this portion of the wiring and I believe there's several threads on how to do it here on Mud if your up to the challenge.
Last edited:
- Thread starter
- #240
Appreciate the thoughts here! I’ll do some research on switching to a volt meter and rerouting this line.
Thank you for the suggestion!