no spark

[cwalton]

I am relaying this issue for my buddy who is up in Maine and also has a 1st gen with some problems. He went to fire up his truck the other day and I guess has no spark. He burnt out a coil last year and is assuming it may be the same problem again. Does anyone have any ideas as to what could cause such a reoccurring issue?

 

[K5dreamer]

is the truck totally stock? or modified?

I'm assuming the battery has a good charge? (12.5 - 13.5 volts)

cant remember if these had points or not, but if so, adjusting the points is a good idea.

check the gap on the spark plugs, try closing them up a little to reduce the gap.

Engine cranks?

tried starting with starter fluid?

 

[cwalton]

Truck has been modified a little bit, but not by him, and not within the past 3 years. Battery is good, the engine cranks, and he tried starting it on my recommendation of putting a little bit of gas straight down the carb and some starting fluid when that didn't work, but he still had nothing. The truck was running just a few days ago, so it seems like something must have blown or fried to cause the sudden issue in my opinion. People have mentioned timing being off to him, but I am doubting that would be off so suddenly for no reason to give no spark at all.

 

[K5dreamer]

any mice issues? chewed wires could be a culprit.

not trying to be insulting, but just shooting out ideas...

starter stator sticking? broken teeth on flywheel? either would cause starter to spin without actually cranking the engine.

broken timing chain would cause cam and dizzy not to turn even if lower assembly was turning, and depending on piston/head/cam combo, its likely a non-interfearence setup which means that could happen without valve contact.

faulty ignition coil is certanly possible.

bad ground connection from engine block to battery/frame.

bad ignition wires could be an issue, arcing to ground instead of the plugs.

has it been visually verified that there is no spark? either with a tester or by removing a plug and holding it against a ground while the engine is cranked?

 

[cwalton]

thanks for the pointers, I'll pass them all along to him

 

[bradshawtech]

Verify the voltage to the coil with the key in the run position...... If it is 12 volts or close to it then he is burning coils by having too high of voltage being fed to the coil.

There is supposed to be a "resistor" wire feeding the coil while in the run mode but it is fed a full 12 volts while cranking that is fed from the starter.