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Author	Topic: Low Ignition Voltage Help
bobbyford72 Journeyman Posts: 10 From: new jersey Registered: Nov 2000	posted 03-20-2001 10:26 AM Anyhelp from you guys would be appreciated on the following item: I have a full size ford '72 Ltd conv. w/400 ci engine. I have an aftermarket points conversion kit installed with a high capacity coil. Car had run fine for quite sometime with this setup, now when I take a voltage read at the coil with key off it is 4.5 volts. With car running it measures between 7 and 8 volts. Engine seems underpowered. I assume I should have anywhere between 9.5 to 11.5 volts when running to properly fire the ignition. Would the low voltage make engine seem to run weak? I assume that all older cars expeirence this problem as they age. What is the best fix? Could the ignition switch be the culprit? Could I wire in a relay between the ignition wire to the coil to bring the voltage back up? Has anyone else had this problem. Any help and diagnostic suggestions would be appreciated. Thanks again IP: Logged
SteveLaRiviere Administrator Posts: 44935 From: Saco, Maine Registered: May 99	posted 03-20-2001 11:33 AM Bobby, it's not a problem, the ignition wire on the older Fords is a resistance wire and you need to tap into a keyed 12v circuit to power your new Petronix {?} kit. I assume the kit calls for 12 volts? ------------------ '72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc '94 F-150 XL 5.8L/E4OD/3.55 Limited Slip '97 Probe GTS 2.5L Disposable Commuter "Keep your driveway all Ford!" [This message has been edited by SteveLaRiviere (edited 03-20-2001).] IP: Logged
bobbyford72 Journeyman Posts: 10 From: new jersey Registered: Nov 2000	posted 03-21-2001 10:33 AM Steve, thank you for your response. Just so I am clear on your answer, I should disconnect the wire that runs from the key ignition (resistance wire) to the coil and run in a seperate keyed controlled 12v power source i.e, from the alternator to the coil and then cap off the disconnected ignition wire. Does sound right? Thanks again. IP: Logged
Moneymaker Administrator Posts: 26813 From: Lyons, IL, USA Registered: May 99	posted 03-21-2001 11:08 AM Correct Bobby. The factory wire had higher resistance for the breaker style points and condeser igntion system. Just replace it with a full 12 volt source ignition on wire. Welcome to M&M by the way ! ------------------ Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member Fleet of FoMoCo products Moneymaker Bio US Class Nationals link IP: Logged

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