voltage at coil

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Nov 19, 2006 | 06:54 PM

79f3504x4

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voltage at coil

Anyone know what voltage is supposed to be available @the BAT terminal on the coil? I have some confusion in my reference books, one says 4.9 to 7.9 volts as there is a resistor wire in the harness,,another says check for battery voltage. I can't find it in my Ford shop manual, as it has a flow chart for checking no spark. My truck has spark, it is just running poorly when warmed up, & coil & module are both getting very hot in a short time.

Nov 19, 2006 | 10:07 PM

Torque1st

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Have the coil and module tested at the local parts house.

Nov 20, 2006 | 07:17 AM

79f3504x4

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Both have been replaced,,I need to know if there is a resistor inline,,if voltage @coil needs to be 4.9-7.9 or battery voltage(12V). Truck ran fine w/new coil for 2 days, now same problem again. Brian

Nov 20, 2006 | 06:38 PM

Franklin2

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If you are working on the 79, yes it should have the resistor. You should read around 8 or 9 volts with the truck running.

Nov 21, 2006 | 12:12 PM

79f3504x4

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Thanks, Franklin. Yes, it is the 79 w/a 400, its the only Ford I own now. I have 11.79 volts w/key on/engine off. Truck stutters under load, I replaced the coil & it ran fine 2 days, then same thing started again. The coil ohms out of spec now,,I am guessing too much voltage has fried it. Truck has no wiring changes ever, I suppose the resistor wire has degraded. I swapped the module for the one behind the seat(had one quit on the freeway once-I have carried a spare ever since) & there was no change. Brian

Nov 21, 2006 | 06:05 PM

Franklin2

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You have to check it with the engine running. With a load on the resistor, the voltage will drop.

Nov 28, 2006 | 04:35 PM

PerfDistIgnition

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No resistor(or resistor wire) is needed with the D.U.I.

If you decide to get a new distributor, consider our D.U.I.-Davis Unified Ignition or our custom curved Duraspark distributor. Please see them at:

http://www.performancedistributors.com/forddui.htm

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