ARCING IN DISTRIBUTOR sensor assembly ?

crownlover

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Apr 12, 2011
Messages
22
Turns out I have a 72 100hp v4 100el72r with a sensor assembly. When i check the sensor with a meter it test that the circuit is closed all the time. Could this be causing the constant arcing in the distributor. Or does the sensor open when the wheel passes by. Thanks for any help.
 

F_R

Supreme Mariner
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Jul 7, 2006
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28,226
Re: ARCING IN DISTRIBUTOR sensor assembly ?

It's a bit complicatd to understand, but the pulse pack sends a small current through the sensor circuit. That creates a magnetic field around the sensor. The lobes of the rotor passing by interrupt the magnetic lines of force that exist, and that changes the current flow, which the pulse pack is able to detect. I believe the word is "reluctance", but forgive me if I got the wrong word.

Anyhoo, it would not cause distributor arcing. Too much resistance in the secondary circuit (plugs, wires, rotor, air gap, etc) will definatly cause arcing. The rule is "Electricity follows the path of least resistance". If there is less resistance across the arc path than across the air gap, down the wire, and across the plug gap, that is where the spark is going to go. Please realize that attempting to do a spark test with too wide a spark gap will create that increased resistance, causing arcing in the cap.
 

crownlover

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Apr 12, 2011
Messages
22
Re: ARCING IN DISTRIBUTOR sensor assembly ?

the arcing is constent with the key in the on position. it will glow red inside the distributor.If you hook a plug up and touch it to ground it will throw about a 1 inch arc until the key is turned off, and shock the crap out of ya.
 

F_R

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28,226
Re: ARCING IN DISTRIBUTOR sensor assembly ?

Whew!! Haven't heard that one before.
 

boobie

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Nov 5, 2009
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20,826
Re: ARCING IN DISTRIBUTOR sensor assembly ?

I've seen a bad power pack do this yrs ago.
 
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