Head scratchinh situation

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dusterdude

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Ok guys,i recently installed a small cap electronic distributor with an external coil.it seems im not getting spark but,my timing light flashes when i crank the engine.im at a loss here and by the way,this is on a carbureted truck.does anyone have any ideas?
 

mxer147

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when in doubt, I pull a plug wire off, put a small screwdriver into the plug socket, lay it across the exhaust manifold, and look for spark. No spark, I meter for 12 volt power at the coil, then to the next component until I find the failure point. If spark, make sure number one lines up with the rotor and the firing order is correct.
 

Redfish

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Ok guys,i recently installed a small cap electronic distributor with an external coil.it seems im not getting spark but,my timing light flashes when i crank the engine.im at a loss here and by the way,this is on a carbureted truck.does anyone have any ideas?

We can assume you stabbed the distributor correctly and that cylinder 1 is getting fire when it is supposed to? And that all the plug wires are re-oriented correctly?

It is possible that there is enough "spark" for your timing light to pick up but not enough spark to arc across the plugs and fire the engine.
 

dusterdude

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Redfish,that is a damn good question.ill check it out
 

dusterdude

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Back to this issue,i am getting 12.5 volts to the wire that plugs into the coil with key on but when i crank i only get about 10.5 volts on this wire.this seems to be recent phenomenon.does anyone where i should look for the drop?thanks
 

rusted nuts

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Back to this issue,i am getting 12.5 volts to the wire that plugs into the coil with key on but when i crank i only get about 10.5 volts on this wire.this seems to be recent phenomenon.does anyone where i should look for the drop?thanks
I would try running a ground wire from Dist hold down bolt to ext. coil 1st,, cheap n easy try
 

dusterdude

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Would i ground the coil end to the hold down bolt on the coil too?
 

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It sounds like your wire from the battery to the starter is 'sinking' more than it should. Possibly due to age. 10.5 volts shouldn't cause an ignition problem tho while cranking.
 

Rickf

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You are having the same voltage drop issue that I have with my '74, however my truck started with a points distributor and the previous owner installed an HEI. To get mine to run I need it to get it spinning (key in start position) then let it go so it is in the run position. When I get around to it I'll eliminate the resistor wire, but for now this plus the extra pedal on the floor act as an anti-theft system.
What are the odds you have a resistor wire floating around?
How many small studs and/or wires are on your starter solenoid?
 

Turbo4whl

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Back to this issue,i am getting 12.5 volts to the wire that plugs into the coil with key on but when i crank i only get about 10.5 volts on this wire.this seems to be recent phenomenon.does anyone where i should look for the drop?thanks
10.5 volts is all you will get at the coil when starter is cranking. The HEI will start with that voltage. What does your new distributor require? Should it have a capacitor wired in to maintain the voltage when cranking?

What is your new distributor, is it made to run with a processor?
 

dusterdude

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Good questions on the distributor,ill have to get with the seller and ask.will advise when i get more info.thanks for the help.
 

hogdaddy

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Which distributor and coil are you using? MSD, ACCEL?
 

Ricko1966

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First thing you need to verify you have spark,take out a plug attach the plug wire clamp the plug body in a jumper cable other end of jumper cable to ground,crank and look for spark. 2nd Make sure you're distributor was stabbed correctly.If the problem isn't solved by then you need to find out what distributor and coil you are running,they don't all wire the same and don't all trigger the same.
 

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