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| Weak Spark https://slantsix.org/forum/viewtopic.php?t=64858 |
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| Author: | polara pat [ Thu May 07, 2020 1:28 pm ] |
| Post subject: | Weak Spark |
Hey all, it's been a while, I'm helping a friend sort out some starting issues on his slant. I'm still in the very early stages of diagnosis but here's where I'm at. Motor is a mid '70s 225 in a '64 Valiant that has been converted to electronic ignition a long while ago. New alternator, dual ballast resistor, maybe other upgrades. It is a Canadian model which means that it has the annoying slow cranking starter, not our usual buzzing reduction gear units. Battery is new but has maybe been run down from cranking too much. If I jump it with my charger I can get it to start but not without so far. First actual question: can I test the 5 pin ECU? I have some spares but wasn't sure of their condition. Basically there is not even a cough without the boost. Thanks in advance |
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| Author: | SlantSixDan [ Thu May 07, 2020 3:13 pm ] |
| Post subject: | Re: Weak Spark |
If it is in good condition (and the battery and cables are also good), the Canadian direct-drive starter cranks the engine faster than the American gear-reduction type. If this one is cranking the engine slowly and the engine won't start without a jump, there's your answer: the battery is discharged or faulty, and/or the cables are faulty, so during cranking the line voltage drops below what's needed for the ignition box to work. |
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| Author: | polara pat [ Thu May 07, 2020 3:30 pm ] |
| Post subject: | Re: Weak Spark |
Quote: If it is in good condition (and the battery and cables are also good), the Canadian direct-drive starter cranks the engine faster than the American gear-reduction type. If this one is cranking the engine slowly and the engine won't start without a jump, there's your answer: the battery is discharged or faulty, and/or the cables are faulty, so during cranking the line voltage drops below what's needed for the ignition box to work.
Thanks Dan, I suspect your right but there's also a bunch of other neglect that needs to get addressed. I'll start with a good strong battery and work back.
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| Author: | wjajr [ Wed May 13, 2020 11:42 am ] |
| Post subject: | Re: Weak Spark |
If Dan's list is all in good shape, and battery has all its cranking amps, suspect the starter having high resistance. Have the battery load tested after it is fully charged, if good, perform starter voltage drop test. |
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