1970 FJ40 1F suddenly stopped running

[DuckyVT]

Hi all, I'm looking to tap the wisdom of the almighty forum.

Truck is a bit of a frankentruck as I got in over my head with rust and just went for it: frame swap from a '73 I think, Aqualu tub/cowl/windshield, but basically bone stock 1970 1F drivetrain down to column shift. In getting it back on the road it got a JimC carb rebuild, new fuel tank, new filters, new fuel line, new plugs, new radiator, new t-stat, and tons of other probably less relevant things.

For the last two summers it's been running like a top. Maybe a bit on the rich side, but super reliable. Turn the key and go.

Near the end of last summer on a zip around town as I pulled through an intersection it stumbled like the key was switched off for a moment and then caught again and took off no problem. Over the course of the day it got worse and worse with the same symptom. Intermittently cutting out. Didn't matter if I was accelerating or steady throttle. Ended up towing it the last few blocks to get home. When I tried to start it she'd crank over and sometimes splutter a little bit but won't stay running at all. Same situation today (somehow, letting it sit in the garage didn't magically fix the problem).

Carb sight has fuel in the middle of the window. Idle solenoid clicks when key is turned on. Gets 12v to coil with key on. Jumper from battery + to coil + makes no difference. Compression is good. Maybe high? Like I'm getting readings above 150 psi.

I'm not sure where to go next. Any ideas? Thanks in advance for the help!

 

[Skreddy]

Good spark? Still points distributor? Checked/changed them lately? Advance mechanism moving properly? Condition of cap, rotor, wires, plugs, broken wire to coil or distributor? Pics?

 

[EWheeler]

Assuming points ignition, or do you have a pertronix electronic unit in the distributor? This sounds like an ignition/spark issue.

 

[EWheeler]

Good spark? Still points distributor? Checked/changed them lately? Advance mechanism moving properly? Condition of cap, rotor, wires, plugs, broken wire to coil or distributor? Pics?

Jinx!

 

[Skreddy]

Jinx!

Are you bored at work too?! Not that I’m cruising the forum at work. No, no.

 

[middlecalf]

Full spectrum inquiry… see anything not normal out the exhaust when it was running, any coolant loss/change? Oil look ok? Engine temp when last running?

 

[B y r o n]

I'd start by checking power connections regarding ignition to include grounds. Sounds like a ground connection was coming loose and then came off or lost connection all together.

 

[DuckyVT]

Still has points. Will check spark as soon as I find a helper. Everything ignition-wise *looks* ok, but hasn't been messed with since well before I got it. I'll order up an ignition tuneup kit even if that doesn't end up being the culprit. Advance is open to air, no hose to carb. JimC suggested that it's actually vac retard on that dizz and had some reason why he recommended to leave it off. Don't remember exactly why at this point, but it had been running just fine that way. I'm just knocking around town anyway.

In answer to middlecalf, everything was in order prior to failure. It has overheated a couple times in the past when the radiator got clogged with some rust slime from the cooling passages accumulated from decades of sitting. No issues since replacing rad. No coolant loss, oil looks good. Exhaust looked normal. Just a little rich as noted before, but always been that way.

 

[Green Bean]

Don't forget to check all of your wiring behind your ignition key. A lose connection or wire there will wreak havoc with the downstream electrical.

 

[DuckyVT]

Don't forget to check all of your wiring behind your ignition key. A lose connection or wire there will wreak havoc with the downstream electrical.

I'll definitely check this, but wouldn't jumping from the battery + to coil + essentially bypass the ignition switch "on" position for purposes of running the motor (maybe not lights and other unimportant things)?

 

[EWheeler]

I'll definitely check this, but wouldn't jumping from the battery + to coil + essentially bypass the ignition switch "on" position for purposes of running the motor (maybe not lights and other unimportant things)?

Yes, it should take the wiring harness out of the equation. You can get a remote start button that will allow you to test things under the hood as a one man operation.

Amazon product

Goes from bat + to solenoid on starter where you ignition switch sends power during a engine start call.

 

[ToyotaMatt]

Hi all, I'm looking to tap the wisdom of the almighty forum.

Truck is a bit of a frankentruck as I got in over my head with rust and just went for it: frame swap from a '73 I think, Aqualu tub/cowl/windshield, but basically bone stock 1970 1F drivetrain down to column shift. In getting it back on the road it got a JimC carb rebuild, new fuel tank, new filters, new fuel line, new plugs, new radiator, new t-stat, and tons of other probably less relevant things.

For the last two summers it's been running like a top. Maybe a bit on the rich side, but super reliable. Turn the key and go.

Near the end of last summer on a zip around town as I pulled through an intersection it stumbled like the key was switched off for a moment and then caught again and took off no problem. Over the course of the day it got worse and worse with the same symptom. Intermittently cutting out. Didn't matter if I was accelerating or steady throttle. Ended up towing it the last few blocks to get home. When I tried to start it she'd crank over and sometimes splutter a little bit but won't stay running at all. Same situation today (somehow, letting it sit in the garage didn't magically fix the problem).

Carb sight has fuel in the middle of the window. Idle solenoid clicks when key is turned on. Gets 12v to coil with key on. Jumper from battery + to coil + makes no difference. Compression is good. Maybe high? Like I'm getting readings above 150 psi.

I'm not sure where to go next. Any ideas? Thanks in advance for the help!

Good spark? Still points distributor? Checked/changed them lately? Advance mechanism moving properly? Condition of cap, rotor, wires, plugs, broken wire to coil or distributor? Pics?

you need :

Dr. NipponDenso here : @4Cruisers

 

[65swb45]

Just take a minute with a screwdriver and open up the point gap a little and see if anything changes.

KISS

 

[DuckyVT]

Following up on this. I finally got around to spending some time with it. Did an ignition tuneup because I'd never actually done that since I got the truck going, and so I could be sure that wasn't the problem. Plugs, wires, cap, rotor, points, condenser. Tried they key and she jumped right to life on the second crank. Seems like it's licked. So nice when problems actually end up being the simple stuff...

 

[65swb45]

Were the old points burnt?

 

[DuckyVT]

I'm not sure how badly "burnt" they need to be to stop working, but they didn't look that bad. I haven't done a lot of work on points ignitions in the past so I don't have a lot of reference.