No Spark
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From: Andrews
No Spark
I have a 81 f100 302, I was having problems with it not starting after I ran it for awhile. I thought it was vapor lock because I'm still running a mechanical fuel pump, took it to a friend after I was running and he said I was getting no spark. So I changed the ign module and the coil and still did the same thing, so I was thinking the distributor, so I bought another one and installed it truck ran really rough so I reset the timing and went back over everything and I got spark from the coil, but none to the wires. I'm stumped
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Joined: Jul 2010
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From: Northeast, OK
I have a 81 f100 302, I was having problems with it not starting after I ran it for awhile. I thought it was vapor lock because I'm still running a mechanical fuel pump, took it to a friend after I was running and he said I was getting no spark. So I changed the ign module and the coil and still did the same thing, so I was thinking the distributor, so I bought another one and installed it truck ran really rough so I reset the timing and went back over everything and I got spark from the coil, but none to the wires. I'm stumped
But, it could be that you have bad wires. Or a bad rotor. Or a bad cap. If the above shows the dizzy is clocked properly then it has to be wires, cap, or rotor. How long has it been since they were replaced?
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From: Andrews
The wire are new and the cap and rotor is only a couple months old and I reset the timing tdc on compression stroke yesterday the rotor at #1 wire on distributor cap and coil was replaced same time the wires was.
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From: Charles Town, W bygod Va
New parts go bad too. I've had to replace new plug wires many times with better quality countless times. Did you buy the cheaper line of plug wires? Your new coil may be weak also.
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From: Andrews
I replaced the old with accel wires and coil, I ordered another distributor just thinking there might be a problem with the pickup. and I plan to try my old ignition module just to see if there's a problem there. and what should the voltage be on the neg side of the coil?
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From: Charles Town, W bygod Va
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Post Fiend
Joined: Nov 2005
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From: Charles Town, W bygod Va
While cranking, hold the coil wire close to ground. Slowly move it away. How far can it throw a spark? 1/2" should be plenty. if you have that, hook it up to the dist cap, remove a plug wire from cap, then hold a grounded wire or screwdriver close to the cap terminal. You should have almost the same strength spark.
If any of the tests shock you, let go real fast!
If any of the tests shock you, let go real fast!
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From: Andrews
While cranking, hold the coil wire close to ground. Slowly move it away. How far can it throw a spark? 1/2" should be plenty. if you have that, hook it up to the dist cap, remove a plug wire from cap, then hold a grounded wire or screwdriver close to the cap terminal. You should have almost the same strength spark.
If any of the tests shock you, let go real fast!
If any of the tests shock you, let go real fast!
Post Fiend
Joined: Nov 2005
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From: Charles Town, W bygod Va
It can't be lighting the test light AND not have voltage. As far as the positive blinking maybe you have the coil hooked up backwards. Doesn't really matter at this point, you have spark to the plugs so it should start.
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From: Andrews
If I turn the vacuum advance all the way toward the water neck on the intake manifold, it fires up then dies. I'm going to check the plugs tomorrow. But the crazy thing is I can set it tdc and rotor at #1 wire on cap and it just turns over. Thinking about setting the timing 20 deg btc