Got a posser..

[username002]

Hello,

I have a 74' Landcruiser FJ40 F engine. Runs great all the time then suddenly won't start. Then suddenly starts, and dies going down road.
Replaced:
Plugs
Condenser
Rotor
Cap
Points
Plug wires
Voltage Regulator
Ignition Switch
Coil
Gap is correct on points, distributor is TDC...

Alternator is putting out correctly. Battery is strong. Getting good spark on spark plug tests and coil tests. Engine appears to fire while ignition is on start but won't continue after starter motor is disengaged.

The question I pose to you is WTF?

-DFG

 

[brewhaw]

Hello,

I have a 74' Landcruiser FJ40 F engine. Runs great all the time then suddenly won't start. Then suddenly starts, and dies going down road.
Replaced:
Plugs
Condenser
Rotor
Cap
Points
Plug wires
Voltage Regulator
Ignition Switch
Coil
Gap is correct on points, distributor is TDC...

Alternator is putting out correctly. Battery is strong. Getting good spark on spark plug tests and coil tests. Engine appears to fire while ignition is on start but won't continue after starter motor is disengaged.

The question I pose to you is WTF?

-DFG

I had that happen and it was a simple wire that had come disconnected from being too loose

 

[Steamer]

Engine appears to fire while ignition is on start
but won't continue after starter motor is disengaged.

First I would turn the key to "ON" and check with meter if you have 12v to the coil.
If not, brewhaw's post could be it.

 

[edwjmcgrath]

Engines need spark and fuel. You've replaced almost everything spark related but nothing fuel related.
When it doesn't start or stops running, open the hood and check the fuel level in the carb.
It should be in the middle of the window.
If you pump the accelerator, you should see a couple of solid squirts of fuel in the throat of the carb.
Basic question, when it fails are you missing fuel or spark?

 

[JohnnyC]

Fuse block... Bad contacts on your ign fuse... Clean the fuse block

Could also be a corroded fusable link... But... Strongly think its fuse block... Had the same issue 16 years ago on my 74

 

[copper204]

Try this.. Run a spare wire directly to battery positive.. Next time it dies.. Clip it onto positive side of coil and try to start back up. If it starts and runs.. You need to dig deep into ignition circuit. I had a bad ignition switch one time do exactly what you are describing. Just saying my expeirence and a quick and down and dirty test. Growing up on a farm 28 miles from town. My dad made us fix stuff with what we had. Could be why my first truck had a 1951 Merc flat head.. Now that was a u-joint snapping engine....LOL

 

[username002]

thanx, thats what i think is going on..do you remember which wire?

 

[DSRTRDR]

I had that happen and it was a simple wire that had come disconnected from being too loose

yup, jumped off the starter on my truck

 

[username002]

Fuse block... Bad contacts on your ign fuse... Clean the fuse block

Could also be a corroded fusable link... But... Strongly think its fuse block... Had the same issue 16 years ago on my 74

the contacts on the ign fuse look fine. the fuse is good. dont think there are any fusable links on this year if i understand what that is. but what is a fuse block?

 

[username002]

Engines need spark and fuel. You've replaced almost everything spark related but nothing fuel related.
When it doesn't start or stops running, open the hood and check the fuel level in the carb.
It should be in the middle of the window.
If you pump the accelerator, you should see a couple of solid squirts of fuel in the throat of the carb.
Basic question, when it fails are you missing fuel or spark?

thats excellent thankyou. i forgot to tell you that shes definetly getting plenty of fuel in the carb. she's even firing when the key is on start. you can hear it.

 

[Rocky_LC]

The '74 had the ballast resistor, and the wire from the starter direct to the coil.

If it runs whe the starter (solonoid) is engaged, but then dies when switched out of the "Crank" position, you are not getting voltage to the coil for some reason from the ignition circuit. Could be:

- Ignition Fuze
- Ignition Switch
- Loose Wire
- Bad Ballast Resistor

If you just turn the ignition to "ON", do you see voltage at the + side of the coil? If not, start tracing backwards...

I liked the suggestion to run +12V to the (+) side of the coil, and see if it runs..... (Don't run it like that for extended periods, you will overheat the coil).

Rocky

Ignition-wise, this is pretty much what yoiu've got...

http://www.yankeetoys.org/documents/wiring_diagram_78_fj40.pdf

 

[LOOMER]

Idle selinoid?

 

[copper204]

Just for info if anyone is intertested.. As a spare emergency kit.. you can buy a 6 dollar porceline sp... ballast from oriellys to put inline of coil power.. buy one for the older fords.. the drop voltage from battery to 10.5 volts to save coil...

 

[Tigerstripe40]

I had a similar problem when I first got my FJ40.
It would cold start and run great.
If I drove it a while and the truck got to operating temperature, if I shut the truck down, the truck would not restart until the truck cooled down, then it would start up and run like a champ.

I went through the ignition and that didn't help. Turns out it was a bad fuel pump. But I would suggest replacing your fuel filters first.

 

[username002]

got it! shes runnin fine! it was a bad contact on the ignition fuse. i had taken it out and inspected it previously but it looked fine and so did not bother to clean or replace the fuse. thanks all so much for your input. its what made it work! at least she got a full tune up in the process. shes my daily driver.