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1997 Thunderbird LX
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Humidity must be the issue. Have you changed out the coil pack?

Joe
 

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Discussion Starter · #24 ·
Maybe grab one on your next junkyard run. ;)
Good luck finding one. Coil packs seem to be a popular part.

Is it possible to open up the coil pack to see what it looks like inside? Or otherwise test it (using a multimeter, assuming I can find the proper resistance values for thus specific unit)?

FWIW, there are no codes according to the Advance Auto Parts guy.
 

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You can check basic operation with a meter, side toward the eec should be less than 500 ohms, or thereabouts, the plug connections 10k, iirc.
 

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Discussion Starter · #26 ·
Update:

Today I actually saw the sparks. First startup after two days of mild rain. Some roughness after startup, which gets much worse when in gear at standstill (I didn't actually drive).

I was unable to capture the sparks on video; however, I could see them clearly. See my arrow in this picture:


There's dielectric grease galore on all the boots. What can I do short of replacing the entire coil pack?
 

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Nothing really. overcoating won't help, it's carbonized the plastic. I have one of these encased in a block of rtv I use for a tesla coil, it's good to 160kv, which is as much as I can measure. Replace it; they're in a ton of 90's vehicles.
 
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Discussion Starter · #28 ·
Replace it; they're in a ton of 90's vehicles.
Any I saw in junkyards honestly looked pretty corroded themselves. New range from over $100 (Motorcraft) to $22 for this aftermarket unit:


Should I trust the cheap version?

What causes that spark any way? Some sort of micro crack in the plastic? I mean where I saw the sparks there aren't any exposed terminals, i.e., the spark seems to go through the plastic (?). How does that happen?
 

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High voltage destroys plastics; it's called carbon tracking. It can happen through the plastic, and these are good plastic.
The aftermarket is nowhere near as good. If you can find one that's not sun exposed, it will work fine.
 
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Discussion Starter · #32 ·
Anyone familiar with the MotoRad brand of ignition coils? I can get that locally for $78.

I did try Rockauto for the Motorcraft part. What a mess. Ordered one week ago. The package was lost by FedEx. Rockauto needed a few business days to let me order a replacement. Now, with the new tracking number, tracking has been saying "Label Created" for the past 24 hours, indicating that they haven't even given it to FedEx yet.
 

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RA has been very inconsistent over the last 3-5 years. I usually look up the parts there and order elsewhere unless there is a major price advantage from RA. For exactly the reasons you're seeing, and more... :(
 

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Pay for the factory Motorcraft coil. Unless you enjoy diagnosing drivability issues. The factory coil lasted 25 yrs. Aftermarket will put you on the "5-year plan".

Al
 
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Discussion Starter · #37 ·
Pay for the factory Motorcraft coil. Unless you enjoy diagnosing drivability issues. The factory coil lasted 25 yrs. Aftermarket will put you on the "5-year plan".
Done. The Motorcraft coil is finally in transit, per FedEx.

However, I don't believe that the factory one lasted 25 years because...the one in the car doesn't look like the new Motorcraft one on pictures (using black filler vs. the light color of the Motorcraft). That's unless they changed colors at some point. I'll take a closer look when I swap them, to see if there are Motorcraft labels anywhere; but as of now, my assumption is that I have an aftermarket unit.
 

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Discussion Starter · #38 ·
Old vs. new. The old one was not a Motorcraft part. Note the "FoMoCo" logo on the new one.




Initial observations: faster starting, somewhat smoother idle, although there's still some vibration in the steering wheel when in gear (which are probably the normal idle characteristics of this powertrain), and no rough bogging or stumbling. However, the real test will occur after the next heavy rain, because the bogging was clearly associated to humidity. I'll provide an update when weather permits ☁🌧🌧☔
 

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Discussion Starter · #39 ·
Rainy/wet day today, but no downpour. Didn't drive any real distance but had to move the car for street cleaning. No bogging issues, but I'll still reserve final judgment until a serious rain storm hits.
Again, the engine started much faster than before. Love it! Hope it's not a fluke. I used to be a bit annoyed by notoriously slow engine starts.
 
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