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Discussion Starter · #1 ·
Hi, I have a 97 Cougar 4.6L, I'm hearing a snap sound under the hood which sounded like an ignition spark, opened the hood and every 3-4 seconds there is a rather large spark jumping from the outside of the harmonic balancer to either the water pump pully or oil pan. Checked all the spark plug wires and they look good, engine ground seems to be good and its running well. Some kind of static build up, I don't know. Anyone know what would cause this?

Thanks!
 

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1995 Thunderbird LX Missing 4.6 MIssing Trans Red
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Hi, I have a 97 Cougar 4.6L, I'm hearing a snap sound under the hood which sounded like an ignition spark, opened the hood and every 3-4 seconds there is a rather large spark jumping from the outside of the harmonic balancer to either the water pump pully or oil pan. Checked all the spark plug wires and they look good, engine ground seems to be good and its running well. Some kind of static build up, I don't know. Anyone know what would cause this?

Thanks!
Likely the balancer is bad. The outside of the balancer has most likely separated from the rubber that holds it to the inside portion of the balancer and it's rubbing on the timing cover as it moves back and forth in a manner it should not.
 

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Heh. Triboelectric effect in a balancer, wow! It must be really cold and dry where you are. :)


EDIT: Hey, I realized this could be bad if it arcs to an EEC-connected wire.
If you heard it in the car, it can kill the eec.
 

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Yikes! You want to quench that arc before something bad happens. My guess is the balancer is separating, and will self destruct pretty soon. Sounds like a wicked buildup of static from the different materials moving in a manner they should not be whilst rotating, building a voltage potential that let's loose in an arc when the potential is too great. It's a good opportunity to underdrive the harmonic if you are inclined to. The aftermarket underdrive balancers are not too expensive and you will gain a little efficiency if you go that route. I usually do the balancer and don't bother with the water pump or alternator sheaves, those seem a waste of money to me. The balancer is not hard to remove, it's just the typical tight and awkward MN12 repair you are used to. I think you will have to remove it to inspect it, it's probably filthy and is hard to see anyway. Good luck, let us know what you find.
 
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Discussion Starter · #5 ·
Thanks guys, ordered a new balancer, the one on there is only a year or so old but not very high quality(ebay). I thought I had an underdrive one somewhere but I can't find it of course lol. I don't even want to drive it until I get the new one on, the spark was a good 1/2" long, could be very bad.
 

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1995 Thunderbird LX Missing 4.6 MIssing Trans Red
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Thanks guys, ordered a new balancer, the one on there is only a year or so old but not very high quality(ebay). I thought I had an underdrive one somewhere but I can't find it of course lol. I don't even want to drive it until I get the new one on, the spark was a good 1/2" long, could be very bad.
Seems like the smart move.
 
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