Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
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Replacing the capacitors in your Fox Mustang EEC? Here is the quick and dirty info you need so that you don't have to look all over the place like I did. I watched every YouTube vid I could find on replacing these 3 caps. I also watched plenty of “how to replace capacitors” in general. I have a slight medical issue that makes my hands pretty dang shaky so tedious work is doubly difficult for me. Electronics on a PCB (printed circuit board) are small and very close. Just take your time though and almost anyone can do this at home.

So what do you need to order?
Capacitors:
You need TWO of the 47uf 16v and you need ONE 10uf 63v. Both are 105degrees rated. I ordered 10 of each since they were so cheap. Use the invoice below to order the exact part numbers. Digikey is great. They pack the order extremely well and it got to me fast. They also had the lowest shipping price. Type the part number in their search block and it goes directly to the part.
DigiKey.JPG

DigiKey Detail.JPG



Solder and Iron:
You need some very thin solder. I like 63/37 (63% tin – 37% lead) rosin core. You want to get as close as you can get to .010 diameter wire. I could only find .030 local. I know it doesn't sound big but it was too big. I made it work but it was a pain. You can use 60/40 if that's all you have local. If you are an excellent solderer you can probably use any of it. Just know that fat solder will drop a lot of solder at one time on your board. It's much better to use the .010 or .015 and add more if needed. Any decent iron will work. If it will burn you 18 times in a row even when you are being careful it's probably good.

Oh...one very important thing I must put here. I had just about given up on doing this project. I had soldered a bunch of stuff over the years. But I “assumed” the soldering iron tip was plenty clean. WRONG! The tips are removable on most irons. Unscrew it and chuck it up in your drill. Take some sandpaper and sand the @#$%^ out of it till it shines. Then put it back in the iron and heat it up fully. Tin the tip completely. The whole thing. If you will do this one thing you won't have the frustrations I had trying to get the solder to release from the tip.

Torx Bits: T9 and T15

A couple toothpicks...preferably unused! If you have a fancy solder sucker you don't need this. I actually like this way better though. After you remove the old caps you can heat the solder once more while lightly pressing the toothpick from the other side. It will slide thru just a touch and clear a nice path for the new caps.
toothpick.jpg


Here is the outside of the computer after being removed from the car. You can see the various Torx screws you will need to remove to open the case. You will have to remove the warranty tape. No more warranty for you...lol

computer-case.jpg

computer-case-back.jpg

computer-case-bottom.jpg


In the view below you can see the torx screws that hold the actual pcb to the remaining case. This pic was to show where the different caps go but we will use it for this as well. DO NOT forget the ones you don't notice like that one in the middle. Don't pry this thing out. If you have all the screws removed it will fall out.

EEC-Capacitor-Locations.jpg


Where do they go? See the above pic. Match the new parts up with the old ones. The capacitors will have a stripe on one side. This denotes negative (most of the time). You must keep these the same orientation as the OEM ones. When you look at the computer so that you can read the A9X as seen in the pic above, all capacitor stripes are on the left. Check the old ones before you remove them!

How bad could they really be though? Well here are mine. One was not connected at all. One had one leg left which means it was doing nothing as well. The third one was still connected but was pretty bad. Sadly replacing all these had absolutely no effect on my car. I'll admit the disappointment and amazement. I don't see how it's possible but I guess it is.

bad-cap.jpg

bad-cap-2.jpg

board-damage.jpg


Cont......
 
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Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
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old-caps.jpg

yikes!

So what do you do? I would remove all three capacitors regardless. They are old. Carefully heat the backside opposite the capacitor body. Put the iron on one leg and gently press the cap sideways. You will feel it tilt over when the solder releases. Then heat the other leg and do the same. Keep doing this until it pulls both legs out and is removed. Do not hold the iron on any spot for too long....ever. If your iron is the correct temp it will melt solder very quickly.

Once you have all three removed you will need to do the toothpick trick from above to clear the two holes at each spot. You also must clean the area even if there is no gunk oozing like on my board. Take one of those “computer screwdrivers” or any really small flat head and very lightly remove that gummy covering right around the two holes at each spot. Then take a Q tip with some alcohol and clean the area. Don't use a ton of alcohol.

Now you can put the new capacitors in. Leave about a quarter-inch of the legs showing under the capacitor body this time. You just don't want them tall enough to touch the case once you put it back together. I don't like them slammed against the pcb because I can't see if they leak that way. This isn't a how-to solder write up so if you need to, watch a YouTube vid. There's some good info out there that will help make this easier. One is, on the backside where the legs come thru, make 100% sure you trim the legs after soldering them so they don't touch anything else. Same with the small mound of solder. It can't touch anything else. Try to make your solder match the others. Make sure the capacitors are secure and you should be good.

That's it. Check everything and reassemble. Hope this helps some folks. At least all the info is in one spot now. I hate searching for stuff!



@91AOD5.0LX Here ya go man.

Good luck.
 
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91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
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This is phenomenal! Thank you for doing all the research, figuring this out, and then putting it all together for us!!!! You touched on everything and having the exact part numbers and where to get them is priceless! Great write up, pictures and all! Now i have to get up the balls to open this thing up and start performing surgery! Lol
Thanks in advance, much appreciated!
 
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HemiRick

I'd be looking at jacking under the house
Jun 28, 2020
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Cleaning the rubber coating off the board, before soldering on the new one's is essential....Do it carefully and thoroughly.
 
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Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
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604
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Cuba, AL
This is phenomenal! Thank you for doing all the research, figuring this out, and then putting it all together for us!!!! You touched on everything and having the exact part numbers and where to get them is priceless! Great write up, pictures and all! Now i have to get up the balls to open this thing up and start performing surgery! Lol
Thanks in advance, much appreciated!
No problem. Hope it helps out. Let us know how much it smokes! :D
 
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Potomus Pete

Gretchen Whitmer is eating at me
Mar 7, 2019
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This is a common problem of coarse, but beginners like myself may be able to do it. The problem would be getting the capacitors. Now we know, and I'm sure this thread will be used for a long time.
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Good job.

Should be added to the tech sticky, but i no longer have the ability to edit that main post to add it.
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Good job.

Should be added to the tech sticky, but i no longer have the ability to edit that main post to add it.
@Noobz347
I don't know if I can do it, I've added stuff to resources and it's still there so I guess I did that right,
I've posted a link in a reply to the tech/how too threads before and got
things added but I don't remember who works in that room anymore.
I'm sure a request could be submitted if there were cookies involved :shrug:
 
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slow84lx

clean it good before insertion
Jul 3, 2005
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Cool write up Wayne, and thanks for posting the capacitor purchasing info. I needed to do this for my 1992 F150 a couple of years ago but was too intimidated to try it. I've never been great at soldering and didn't want to screw up a board. A reman from RockAuto did the trick but was pricey. I should have researched it a little bit more.
 
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Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,114
604
143
55
Cuba, AL
Cool write up Wayne, and thanks for posting the capacitor purchasing info. I needed to do this for my 1992 F150 a couple of years ago but was too intimidated to try it. I've never been great at soldering and didn't want to screw up a board. A reman from RockAuto did the trick but was pricey. I should have researched it a little bit more.
Thanks. Finding the correct capacitors was my only worry. After lots of searching I worked it out. Luckily didn't melt anything...lol.
 

Wayne Waldrep

Before I post a pic, do you have one of yours?
15 Year Member
Apr 14, 2003
1,114
604
143
55
Cuba, AL
Good write up. I did mine about 6 months ago. I also have a spare A3M I plan on doing at some point.
Thanks Dan. I need an A9L right now. Just don't have the $$ at this point. My over generous self gave away the 2 or 3 extra I had long ago.