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Wont start, electrical

jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
Last ran:
302, 4 bl edelbrock, msd 2 blaster coil, stock distributor with pertronix ignitor, centech harness, stock alternator. all parts less then 300 miles on them.

what changed:
i pulled the carb and installed offroad needle and seat, adjusted flots and added electric choke.
i wanted to adjust the timing so i hooked up the remote starter switch (did it incorrectly at first - hooked to left side of solenoid and to right side. nothing happened then i went to get the directions. decided to play with timeing later if needed.
wont start, cranks but wont fire. carb putting out fuel when i pull the throttle, so it gets gas.
no spark to engine.
coil got way hot from cranking.
checked coil, got spark from coil, none from plug wire.

What I changed out:
new stock points, new stock coil
got out meter.
Battery shows 10 volts.
coil positive side gets 8 volts
ceramic resistor takes in 10 volts, puts out 8 volts
no spark coimng out of coil (new or old now)
fuses all good.

what do i need to check next?
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
checked coil, got spark from coil, none from plug wire.
Sorry for asking this, but, is the rotor under the distributor cap?
no spark coimng out of coil (new or old now)
Verify voltage at the + side of the coil. Disconnect the distributor from the - side, and connect a short ( 12" ) piece of wire. Have coil wire connected to coil but free on the distributor end so you can check for spark. Touch short wire to engine block for a moment, then lift. When you lift the wire from the engine block you should get a spark from the coil.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
yes rotor is under the cap on this type.

the coil should have power to the negative termial just when its cranking or when the key is in the accessory position?
 

brian72

Early Bronco Student
Joined
Jun 18, 2001
Messages
4,157
battery shows 10 - that is not enough....surprised the solenoid is not clacking...
Ask me how I know this ;) %)
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
should'nt i still get some spark?
i will hook up to my pickup battery at lunch and see what happens. i sure hope it starts.
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
yes rotor is under the cap on this type.

the coil should have power to the negative termial just when its cranking or when the key is in the accessory position?
Coil should have power to the + side with the key ON or START, not in ACC. Negative side may or may not show voltage (with the distributor hooked up), depending on whether the points are open or closed.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
put a diffrent battery on, no help.
lets talk points. the black wire from the coil goes to the front side of the points where the ground is connected?
or should be go to the back side where the ballest thing is connected?
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
put a diffrent battery on, no help.
lets talk points. the black wire from the coil goes to the front side of the points where the ground is connected?
or should be go to the back side where the ballest thing is connected?
Ballast resistor is connected to the + side of the coil. - side of the coil is connected to the distributor, actually to one side of the points. The other side of the points is "connected" to ground internally through the distributor.

When the points are closed, current flows through the coil, through the points to ground. This creates a magnetic field in the coil. When the points open, the current flow stops, the magnetic field in the coil collapses (much, much faster that it is created), and it's this collapsing magnetic field that creates the high voltage for the spark.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
by ballest, im talking about the cylinder item under the rotor/cap.
sounds like i have the wireing wring on the points. from your description.
 

70_Steve

Old Guy
Joined
Dec 13, 2002
Messages
8,317
by ballest, im talking about the cylinder item under the rotor/cap.
sounds like i have the wireing wring on the points. from your description.
That cylinder thing under the distributor cap, with one wire that connects to the points, is a Condenser (capacitor). It's just there to reduce arcing at the points when they open and close, and make them last longer.

I'm not familiar with the Centech harness, so I don't know if that harness uses a resistor wire or a ceramic ballast resistor.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
the centech does have the cermaic (your words ballest resistor).
the condensor and the - wire to the coil should be hooked up on the same screw? (the condensor is on the rear of the points and the grond is on the front of the points?
front towards grill, rear towards the cab.

it all worked well until i fixed the carb.
wahhhhh, i would like to drive my truck.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
i looked again, i see a open spot on the points itself, on the side of it for a wire. i hooked the coil - wire to it.
i think i got the wires in thw right place now.
still no start though.
 

wpaeb

Sr. Member
Joined
Mar 19, 2005
Messages
429
Loc.
Clarion ,PA
Not sure what you mean by front and back of points. The condenser and coil - wire hook to the stud that is perpendicular to the disy shaft on the points moving arm. the 2 screws that hold the points in do not get any wires.
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
ok, great, i had the condensor hooked to the wrong place then, i had it on the back of the plate on that screw.
i swaped it up to the side of the points arm with the - wire from the coil.. oh i got something, it tried to fire up. but the battery is sucked dry now. uaghhhh
after work i will get my jumps out and try again.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
This won't help you get it running, but when you do get it all dialed in and re-install your Pertronix Ignitor, make sure that it is getting full battery voltage.
Only the coil and points need reduced voltage from a ballast resistor. The Ignitor prefers full voltage.
Then again, you're also running a Blaster coil. Verify what MSD recommends for the model you have. Some take the full 12 volts, others take a resistor.
Good luck.

Paul
 
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jim02

Full Member
Joined
Jul 31, 2007
Messages
195
Loc.
Denver area
its running now as for electric is concerned.
the msd and the ignitor (models i have) directions said to leave the resistor in place.

now i need to keep the carb delivering fuel. i called edelbrock and will try what they said tonight.

thanks for the help everyone
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,275
...and the ignitor (models i have) directions said to leave the resistor in place.

Glad you got it running. But re-read the Ignitor instructions next time you get the chance and look closely at the diagram.
They may say to keep the resistor in place, perhaps for the sake of the coil for some reason or just to cover their butts, but they also say to make sure to hook the Ignitor to the HIGH side of the resistor. That way it gets the full 12 volts.
If they're still using the same lousy diagram in the instructions that they've been using for the last ten years or so, it's hard to see at first. But it's there. In the picture, the wire is hooked to the resistor, yes, but it's hooked to the battery side. NOT the coil side.
They even say that if you're using a resistor-wire (like stock in a Bronco) instead of a separate ballast resistor (as in their diagram) then you should run a separate wire to the Ignitor's red wire from a full 12 volt keyed source, and NOT to hook it to the coil's positive like they say so often in their text.

Just like I said in another Ignitor post though, if they've changed things over the last couple of years, then call them to verify, but if it's the same old Ignitor (which I'm pretty sure it is) then it needs (or at least prefers) full battery voltage.

I even got that straight from their tech guys one time when I questioned this same thing. It's happiest with full voltage.
Since yours IS running, it's obviously not a major thing you need to deal with right now. I just wanted to mention to you, and any other Ignitor users reading this, what I got from the instructins and what they've told me over the years.

Paul
 
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