Ignition/Distributor Problems please help!! (1 Viewer)

[dfnngsilence]

Hey everyone,

Newbie here...
Long story short we got a torrential rain a couple days ago and afterwards my '72 FJ40 wouldn't start. Normally it cranks and starts right up. Now it'll crank all day but there's no spark.
I've checked it's getting fuel, the ignition coil is good sending a spark to the distributor, and the distributor contact points (don't know the technical term) arm is pivoting during cranking.

Should there be spark between the points during cranking?
I've pulled the plug wires am not getting any spark from the plugs.

I've attached some pics just in case.
I cleaned the contact points in the cap to make sure they're getting a good connection; and i've exhausted the search function hoping to find some clue.

Any advice or suggestions would be great.

Matt

 

[Trollhole]

Check the cap and make sure it's dry. Get some fine grit sandpaper and slightly sand between the points. My bet is your points. Should see a small spark on points. Best to do it at night.

 

[John McVicker]

My guess is also points/point gap.

Ballpark for point gap is about the thickness of match book cover paper. Not 100% but will get it started if that's the problem.


John

 

[dfnngsilence]

My guess is also points/point gap.

Ballpark for point gap is about the thickness of match book cover paper. Not 100% but will get it started if that's the problem.


John

So the two points inside the distributor: one on the pivot arm and the other stationary point need to be the roughly the thickness of Matchbook paper apart. Is that when they are separated when the arm kicks back from the rounded side of the shaft or in the closed position on the flat portion of the shaft(laymans terms)?



Oh and GREAT avatar John!
"We’re surrounded. That simplifies our problem of getting to these people and killing them." — "Chesty"

 

[John McVicker]

So the two points inside the distributor: one on the pivot arm and the other stationary point need to be the roughly the thickness of Matchbook paper apart. Is that when they are separated when the arm kicks back from the rounded side of the shaft or in the closed position on the flat portion of the shaft(laymans terms)?



Oh and GREAT avatar John!
"We’re surrounded. That simplifies our problem of getting to these people and killing them." — "Chesty"

Yep, the gap is measured at it's widest point... as it opens.

W/cap off, rotate the engine by hand until the points are open at its widest. This will be at one of the six points on the dizzy shaft that moves the arm...which causes the points to open.

Then loosen the screw on the points and then w/flatblade screwdriver, adjust the point gap to the thickness of the matchbook cover. Very bad description...but you will see what I mean.



If you are working alone, pull the fan blade towards you to rotate the dizzy shaft to open the points. Or gently stick a screwdriver in the alt. blades to rotate the engine. Or just keep clicking the ing. key until you get lucky.

And yes, Chesty was 'The Man'.

John

 

[dfnngsilence]

Tried that it and spaced the points to the appropriate distance. Still nothing.

I replaced the 15amp fuse.

Question: In the top picture what is the white insulator attached to the firewall that the red wire is plugged into?

I'm really confused. The distributor turns but there is no spark between the points.
HELP!

 

[spotcruiser]

If you are working alone, pull the fan blade towards you to rotate the dizzy shaft to open the points. Or gently stick a screwdriver in the alt. blades to rotate the engine. Or just keep clicking the ing. key until you get lucky.

Just for future reference, if you need to turn the engine for things like valve adjustments and setting points, just put the transmission in 4th gear, let off the parking brake, and gently push or pull or rock the truck by hand. Don't pull on your cooling fan or pry on your alternator fan. You're just going to hurt yourself or damage parts.

Of course, the caveats to make sure you're on level ground so the truck won't roll away and/or make sure you take the truck out of gear before cranking the starter apply here.

With the ignition on, do you have 12V at the ignition coil (terminal with the red wire)?
Do you have continuity through the coil (ignition should be off for this)? What is the resistance of the coil?
With the ignition off and the points closed, do you have continuity from the (-) terminal (black wire) of the coil to ground?
With the ignition off and the points open, do you have continuity from the (-) terminal (black wire) of the coil to ground?

Another caveat: Don't leave the ignition on longer than required for making the voltage check at the coil. You can overheat your coil by leaving it energized when the engine isn't running.

 

[spotcruiser]

Just re-read your original post. You have verified that you have spark from the coil secondary wire at the distributor cap?

That implies that your coil and points are working. Did you put the rotor back in the distributor? I have seen cases where the rotor was so worn that the spark would no longer jump the gap to each cylinder contact in the distributor cap, but I think that's a pretty rare occurrence. Is the cap in good shape (no cracks)?

The white insulator upstream of the coil is a ballast resistor to limit primary current through the coil.

 

[John McVicker]

Good point on the rotor. And not to be too basic, but you are putting it back on ? I don't see it anywhere in the pics.

Any unwanted back & fotrh movement of the dizzy shaft ?

John

 

[dfnngsilence]

I checked the coil using a 9v battery and a spark plug it sparked no problem...
The rotor is worn, but didn't looked worn out, I hit it with some sandpaper just to make sure it is getting good contact.

There doesn't seem to be any movement on the dizzy.
I also tried a different coil from my buddies 40...no dice.
Pretty frustrating...
Could it be a compression issue?

 

[spotcruiser]

I checked the coil using a 9v battery and a spark plug it sparked no problem...

So, you checked for spark out of the coil, but you have no spark at a spark plug while cranking (keeping in mind that the plug body must be grounded, or checking for spark from the plug wire to ground)?