Intro and electrical question

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Jun 2, 2022
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MA
Hello,

I have 1972 FJ40 which my father purchased when I was a toddler, I grew up using it and enjoying during the summer when I was old enough to drive and it hasn't seen a northeast winter, as it stays garaged in the winter. With my kids growing up and various obligations meant it sat for the last 3 years (had a potential brake issue that need to be looked). Well, I want to get this on the road again and decided to get it started and double check everything, and get brake work done if needed. The problem is that it seems to now have electrical issue, and getting power to the distributor appears intermittent. Most everything is stock on the FJ40 and it was running fine when last put away. I'm alright with the basics, but not a mechanic.

The details:

1. Build date= May 1972
2. Approx 50K original miles (has been in my family since 1972)
3. Was running 2-3 years ago, had some brake issues to address and has been sitting

Right now it won't start. The details are:

A few weeks back I installed a new battery and went to start it, and it turns over, but doesn't fire up/catch.

1. I figured fuel might not be good, but getting fuel to carb and fuel filter changed
2. Decided to check for spark, but no spark
3. In good shape or replaced:
* Dist Cap
* Rotor
* Condenser
* Ballast resistor
4. I bench tested the ignition coil and these results
* Primary 1.7 ohms (@200 on meter)
* Secondary 11.72 - 12 (@20K on meter)
5. I bench test the ballast resistor and got these results
* Original 2.9 - 3.5 ohms
* New 2.1 -2.2 ohms
6. I did clean as many grounds as I can find (saw that as potential culprit in these forums)
7. Looking to find the old service manuals we have to see what the coil results should be and these are in range?

Most recently I used a test light with key in run position (but not cranking) and observed

1. Light at ignition coil (top of resistor)
2. Dimmer light at ignition coil (bottom of resistor)
3. Intermittent light at bottom coil which leads to distributor is (mostly no light, although on 2 occasions there was a light and there was light a the points as well)
4. Have seen spark at the points once, but generally nothing

Looks like SOR carries new ignition coil for a vacuum advance distributor, but I think this vacuum retard (?) If it is the ignition coil what are my replacement options?

Thanks for any advice or help you can provide!

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Lucky dog!

You hit all the usual suspects. :popcorn:
 

DPV7070

ForceFed40
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I have a 6/72 and used the hell out of this wiring diagram when I first got it. Sounds like @Malleus has a good point to check the condensor. You could also look into a Pertronix system if those are still recommended?

Last thing - double check the plug wires and or the orientation of the distributor cap.



WIring Diagram_FJ40.jpg
 

Skreddy

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I’d start by replacing or at least cleaning the points, then checking points gap (and dwell if you can).
 
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If it has been sitting for years there could be corrosion at any of the connection locations. Try pulling the plug wires from the plugs and cap. Look for signs or corrosion and clean all before reconnecting. Pull the plugs and do the same thing, clean and then re-install if they look good or replace with new. Flush the fuel from tank and carb and fill with new fuel. Also, remove and clean all fuses and connection points at the fuse block.
 
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Malleus - Thanks, I do feel fortunate to have this FJ40

DPV707- thanks for the wiring diagram, much appreciated. I did swap the condenser out just in case, but unfortunately didn't change the results. Wires we changed out when tuned up 3 years ago, still looking good. Plugs were OK, I cleaned them up early in the process; I do have some new one's on hand that I haven't put in yet.

Skreddy - points looked good, did a light cleaning already just in case.

Byron - Fuses, I thought that was going to be it the other day. I found the ignition coil fuse in drivers side footwell for the ignition, but was still in good shape no corrosion. That being said, maybe I go back and put a new fuse in and clean up just in case. Any other fuses I should be looking for?

Seems like if I can get power to the distributor consistently* that would be mean power to points, plugs, etc. I found some old manuals last night, will see if there is anything about readings for ignition coil.
* simple light test is showing mixed results has me stumped
* having someone look at points while quickly turning over results in generally no spark (we did see a spark once)
 
Joined
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Thanks John Smith - I do have new points that could be the next step.

Ackcruisers - thanks for the documentation with points gap and dwell angle and more.


Work and family commitments to deal with for a bit, will look to get back to troubleshooting in the next few days
 
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Hi all - I just wanted thank everyone again for their input. I had time over vacation 2 weeks ago to continue troubleshooting, long story- short changing the points did the trick! Learned it wasn't difficult to install new points and set the correct gap. Started right up after. All in all it was good that I went through everything I did, because I cleaned up connections, replaced an old rubber fuel line that was on its way out, removed old gas, etc. Cheers!
 
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Last piece of context the points "looked" good when inspecting without removing, and I had cleaned up a bit in place, but upon removal and closer inspection they were in fact pitted pretty well in one location, etc.
 
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I can't tell if your starter has the lug for bypass, but with your external ballast resistor coil, there is usually a wire connecting the coil to starter to bypass the resistor, which will give you a hotter spark while key is in start position. This could be a reason the points failed.
 
Last edited:

Coolerman

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I just finished fully documenting an early 1973 Main Cowl and rear chassis harness. The schematics that have been posted are wrong in many areas.
Example #1: The 73 harness has the wiring for the ballast bypass circuit but to my knowledge the 1973 FJ40 did not use a ballast resistor in the US. Maybe this was used in other markets?
Example #2: The 73 (and 74) harness has the weird wiring for a vacuum switch/solenoid/relay for the t-case that apparently the US never had. Again probably for other markets.
Example #3: The schematics out there also show wiring for a 4WD light which again the US market never had.
Example #4: The 73 rear chassis harness has an extra two pin connector that has GL and GB wires that appear to have no function and are not shown on any schematics I have.

I also added a modifed 72/73 schematic to the website that gets rid of the trailer switching crap to make it easier to read.

Haynes1973FJ40WM.jpg
 

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