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.
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.
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
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.
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.
Cont......
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.
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.
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
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.
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.
Cont......
Last edited: