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Discussion Starter #1
I decided to replace my cap and rotor today because coolant had sprayed all over the old distributor, and I had no idea how old they were anyway.

I *tried* to do the smart guy thing of moving one plug wire at a time over to the new distributor cap, but there just wasn't enough slack in the wires to do so.

I'm sure you see where this is going.

I pulled the rest of the wires off, put on the new cap, and put the new wires on. The Bronco proceeded to run crappy. Horrible vibration that shook the whole truck.

I first tried the standard firing order, 1-5-4-2-6-3-7-8, as below.

1 8
5 7
4 3
2 6


When that didn't work, I remembered the guy I bought my motor from telling me it was an HO... which I didn't believe. But, I tried the HO order anyway:

1-3-7-2-6-5-4-8


1 8
3 4
7 5
2 6

That didn't work, either. The truck ran even worse.

As it turned out, the parts store gave me the wrong rotor, so all I replaced was the distributor cap. I'm assuming it's on correctly, with 1 at the back, as diagrammed.

Could it be a bad plug wire, or what? The plug wires are in pretty bad shape. (UPS is bringing me Ford 9MM's.) The only other thing I did was use some throttle-body spray to clean out the throttle body.
 

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Ex Navy Nuke
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5,420 Posts
Lets clarify this. Are you calling your #1 cylinder the front pass side one? 1-4 are on the pass side front to back and 5-8 are on the driver's side front to back. There should ba a "1" marked on the dist cap for #1 spark plug and then your firing order is CCW(counter clockwise) around the cap from #1. You have the correct f.o.'s listed for 302 and 302HO/351 so the plug wires must just be in the wrong place.
 

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Discussion Starter #3
Got it. It must have been a bad plug wire... I replaced them with a set of house-brand wires, and it runs like a champ. At least it did after I went with the HO order. I'll be damned - the guy wasn't full of it. :)

Man, the difference is night and day. The old rotor and cap was coated in antifreeze and fairly corroded. Now there's CRISP throttle response, and my rough idle has smoothed out.
 

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Ex Navy Nuke
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5,420 Posts
It's not uncommon for one or more plug wires to come apart inside when you pull them off the spark plug. Over time they will corrode onto the plug, this is one reason dielectric grease is a good idea on your plug wires at both ends.
 

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Discussion Starter #5
Tomorrow I'm going to Seafoam and then change the plugs. I'll definitely put some dielectic grease on them. The old plug wire ends were pretty corroded.

Man, maybe a properly working ignition will get me to 8mpg. :)
 
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