1975 Dodge Truck truck has no spark

Tiny
OLDDODGETRUCK
  • MEMBER
  • 1975 DODGE TRUCK
  • 5.2L
  • V8
  • 4WD
  • AUTOMATIC
  • 133,000 MILES
My dad was driving the truck and it all of a sudden starting running rough. He stopped to look at it and it wouldn't start again. So far I've replaced the resistor, coil, points, and cleaned and gapped all the plugs. I checked to see if their is power going in the coil and it's about 7 volts. The rotor spins, but when I put the timing light on there is no spark in the plug wires. I have no idea why the spark is disappearing. The rotor, cap, plugs, and wires are all pretty new. The cap and rotor don't have any scorch, marks on them. What is going on?
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Thursday, September 4th, 2014 AT 3:23 PM

8 Replies

Tiny
HMAC300
  • EXPERT
I fyou have spark at the coil wire where it goes to the dist cap thenit's either the rotor is cracked or the dist cap. If it 's not firing on pug wires. Check gap o fpickup coil should be >008-.010" use a non magenetic feeler gauge with vacuum advanced. Check positive side of coil if at 6-7volts and negative side very low or zero volts then control unit is probably bad.
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Thursday, September 4th, 2014 AT 4:12 PM
Tiny
OLDDODGETRUCK
  • MEMBER
No pickup coil
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Thursday, September 4th, 2014 AT 7:02 PM
Tiny
HMAC300
  • EXPERT
If this truck has points it 's the wrong system so if that is what you have then it's the wrong system in it and replace points and condenser also check coil for resistance. Go to our site under tune up if you don't know how. Also the pickup coil is in dist.
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Friday, September 5th, 2014 AT 6:23 AM
Tiny
OLDDODGETRUCK
  • MEMBER
The engine is a '69 industrial from a case 1020 combine, the guy who did the engine swap used parts from the original engine and the combine engine. I just replaced the points, ignition coil, condensor, cap, plug wires, and plugs. There is 11 volts going to the resistor and 7 volts to and from the ignition coil is this enough voltage?
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Friday, September 5th, 2014 AT 8:18 AM
Tiny
HMAC300
  • EXPERT
Should be 12 to resistor and about 9 after. See if spark comes from the coil if it doesnt' it's a wiring or points/condenser issue if spark comes from coil but not to spark plugs then it's a rotor or dist cap issue.
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Friday, September 5th, 2014 AT 9:35 AM
Tiny
OLDDODGETRUCK
  • MEMBER
Tomorrow I am going to replace the cap and rotor again to see if something is defective there. I'll also try to find somebody to help me so I can see if power is going to the distributor or not.
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Friday, September 5th, 2014 AT 10:23 PM
Tiny
HMAC300
  • EXPERT
I have no further suggestions or comments
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Saturday, September 6th, 2014 AT 6:00 AM
Tiny
OLDDODGETRUCK
  • MEMBER
Okay, thanks for your help.
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Saturday, September 6th, 2014 AT 6:21 PM

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