Help Needed, No Spark

[blown240]

My 66 Suburban just got towed home. I drove it to a buddies this morning and it was fine. Go to leave and it wont start. Its got fuel put no spark.

Spark was weak at first, so I replaced the points and condenser with a Petrinox. I also put a new petronix coil in. Then I had no spark at all.

I checked the ignition switch, and it has continuity and 12v going in. At the coil + I only have 6 volts. Plus for a while it wouldnt crank, now it will. I found a broken yellow wire at the coil +. But with it attached it still wont start, so mayke that wire was cut on purpose.

Battery is on the charger. Its a 305 V6, with a 2 bbl.

Any ideas?

[61_FL_Apache]

Is there any voltage on the yellow wire? Also, do you know where it is on the other end?

[blown240]

There is no voltage at the yellow wire, Schematic shows it going to the starter, but I have 2 wires on my coil (yellow/Blue) and the schematic only shown 1.

[Hottrucks]

run a jumper from the + to the coil and crank it if it fires you have a wire issue...the wire from the key to the coil is a resistor wire I bet you have an issue there...or...the yellow wire from the starter ( which should give 12 volts when cranking)

[blown240]

I jumped a wire from the + side of the battery to the + side of the coil, and nothing. Then it wouldnt crank for a while. Now it cranks.

If the wire from the key to the coil is a resistor wire, do I still hook up the petronix to the + ad - sides of the coil, or does it need a non resistor wire? That may be why it wont start.

[Hottrucks]

now I'm confused???

when i get in a bind I start back wards...nothing on the coil but a + and the - to the dizzy..( this will ussually get you home but with the higher voltage to the coil some times it doesn't like it but will ALWAYS make it run) if it runs then great if not theres a point or condenser issue..if it runs trace the wires back and keep measuring voltage and I'm sure you'll find something fishy

[blown240]

I went out just now and tried jumping the battery to the coil, still wont start. So I took out the petronix, got the old parts, sanded the points, and put it back in. Tried jumping battery to coil again, and still no start.

Coil only has the positive from the battery, and negative from the points. And of course the coil wire. The coil I am using is a new coil.

[blown240]

I went out this morning to test the new coil. It and the coil wire are good. So I hooked it up with a jumper to the battery and the points. The stupid thing fires right up! This is with the old points and condenser in it.

The only thing I can think of that changed is that it is now cold outside. So I am going to put a new cap rotor plugs and wires in. Then I will get it going on the points, and switch to the petrinox. Hopefully it will continue to work.

[Hottrucks]

ok pull the cap and see if there is voltage at the points ( Ive seen the wire go bad or ground between the points and outside) then use a screw driver and with power on put a plug in the coil wire and open and close the points with a small piece of something and see if the plug sparks...you could have a bad cap or rotor??? I have even seen the dizzy have a bad ground..yea I know the stuff you see over the years will blow your mind sometimes

[blown240]

Well I ended up putting in a Petronix ignitor and a Flamethrower coil. I also put in a new cap, rotor, and wires. I got plugs for it but I dont have a socket with a thin enough wall to fit. I also ran a 10 gauge wire from the non fused switched terminal in the fuse box to the coil.

At this point I was trying to get power to the coil while cranking. The old yellow wire to the coil showed no voltage with the key in the on posisition. The other black or blue wire had voltage jumping all over the place from 5 to 11 volts. So I hooked the yellow wire up to give me 12v when cranking.

Now with the truck running it runs AMAZING. But it is still hard to start. I am going have to check the timing the carb.

PS - I now know what it feels like to get shocked off the coil.