Any Foxbody gurus on here?

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My89Foxbody
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Posts: 2
Joined: Mon Jun 01, 2020 12:36 am

Any Foxbody gurus on here?

Post by My89Foxbody »

I see probably Steve from Drag Radial Performance who works with Foxbody hasn’t been on since June 2019 so, maybe someone else can help.
I have a 1989 Mustang GT. It’s bone stock with exception of headers, catless H and aftermarket mufflers.
It has 40,000. roughly original miles.
I have been trying to work through it have a slight stumble.
So, I went to check timing to verify it was close to 10* and my timing light wouldn’t trigger when on the #1 plug. I then checked other wires and it worked fine.
I broke out my incandescent spark test light and indeed the #1 was barely showing spark but, the others where fine.
Here’s the weird part when I pulled the spout spark is fine at number #1 cylinder.
I swapped wires from adjacent cylinder and it’s not the plug wire.
But, for the heck of it I went ahead and installed new Motorcraft plugs, wires, cap and rotor.
Also, weird with spout out the timing was retarded to 23* and it’s suppose to be set at 10*. So, since the timing light does work on #1 with the spout out I set timing.
I then moved timing light to adjacent cylinder and verified PCM was advancing timing by unplugging and plugging in spout. It’s advancing as it should.
What am I missing here?
What would possibly cause the #1 cylinder to show weak spark when spout is in but, not when it’s out?
I would think if the pcm had an issue it would effect all cylinders.
Could it be the PIP in distributor or TFI module?

Little lost on this one so, if you guys have any ideas or have ever seen these chiming in would be greatly appreciated.

Thanks

My89Foxbody
Newbie
Posts: 2
Joined: Mon Jun 01, 2020 12:36 am

Re: Any Foxbody gurus on here?

Post by My89Foxbody »

I have done testing and more testing and maybe I have found the issue.
There are three capacitors in these and I have read they can leak and cause all sorts of issues with the way the car runs etc.
Of the three one capacitor has the green fuzz/blob of death from my untrained eyes.
It looks nothing like any of the other legs on the capacitors (see pictures).
I cannot find what exactly this one of the three capacitors in my pcm does but, I would think it might be related to my issue.
I have a remanufactured PCM with newly installed capacitors coming so, I reckon I will find out if that cures the problem,

Does anyone know exactly what this capacitor relates directly too in the 1989 Mustang GT (A9L) PCM?

Bottom picture is good leg side of leaking capacitor (nice clean etc)
Middle picture is other leg side showing light greenish blob .
Top picture is the location of one leaking capacitor in PCM.
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