vacuum hose to distributor

[artist]

I have a 1979 South American FJ 43. with what looks like a HEI, there is no hose connected to the vacuum diaphragm on the side of the distributor, nor is it plugged. I have been having starting problems and removed a spark plug and held it against the engine while connected by the spark plug wire. someone turn the engine over, the solenoid clicked, the started spun but there was no spark at the spark plug. after several other turning of the key, all of a sudden the spark plug had spark and the engine fired. This has been an on going problem and I can not depend on vehicle starting. So I decided to opt for a new HEI system. Which one do I get, one with vacuum advance or one with mechanical advance? and if so where does the hose go from the vacuum advance? or do I plug it?

 

[Grayscale]

Before you do that, check the function of the ignition switch.

 

[Pighead]

It might be good to find out why you're not getting steady spark first. If the real problem is a bad ground or loose wire a new dizzy won't fix it.
Do you have a source for ported vacuum on your rig? Pics would help.

 

[pb4ugo]

All distributors have mechanical advance and is the engines primary advance mechanism. Vacuum advance is pretty much unique to automotive engines. The automotive engine is not under load all the time, like when going down hill or the foot is off accelerator. The engines vacuum goes up and the vacuum advance increases the timing making the engine run more efficiently when power is not needed. Under load the throttle blades open and reduces the engines vacuum and reduces the advanced timing. Service engines usually are under load all the time so they use only mechanical advance and typically don't have vacuum advance. Other will chime in where to hook up vacuum advance.

 

[artist]

Before you do that, check the function of the ignition switch.

so what do you mean the ignition switch? the one on the steering column where you turn the ignition key? the previous owner added power steering from a fJ-80? so it is not stock to my fj-43. what am I looking for in the steering column? it looks like it has a plastic sleeve around it that I could take off. with wires running up the steering column. As far as checking wires in the engine bay I have gone through battery, starter, ground, coil wire connections; unbolted them, cleaned them off and reattached every thing. That is why I was leaning to old or worn out electronic parts of the HEI system. thanks for any more suggestions

 

[charliemeyer007]

Sometimes the contacts in the ignition switch go bad and can cause intermittent spark. Giggle the switch while cranking and have someone watching the spark.

 

[pb4ugo]

I think @Grayscale's comment might be in regards of your testing that you weren't getting consistent spark at your plugs when you were checking for spark. There has to be a reason for that and it might not be in the distributor itself, but somewhere between the distributor connections and the ignition switch and it could be the switch itself.

 

[Grayscale]

Use a test light. Probe it to the low-voltage side of the coil/HEI.
You can also disconnect the battery, and test for resistance (Ohms) between the battery positive terminal and the HEI low voltage lead (ignition 'On,' and 'Start'), with the key in these two positions.
You might perform a voltage reading between the low voltage hot side of the HEI and the battery negative, with the ignition set to 'On.'
You should also check for connectivity between the distributor body and the engine, and the engine to the frame, and also engine to battery negative. As Pighead mentioned earlier, grounds.