[MustangStudFarm]

I have been chasing problems for a while and I finally found the problem. It was bad capacitors on the ECM. I had been surfing the web for several days and most of the threads that I read had no solution. So, I thought that I would post this. 2 of 3 capacitors ended up being bad. I saw the "green fuzz" on the leg of a capacitor and closer inspection showed that the leg had actually burned off.

 

[AlexLTDLX]

Good catch. Electrolytic capacitor failures are probably 90% of modern electronic failures. The insulation between the plates is literally nothing more than a oxide layer on aluminum foil. When these caps fail, they can cause a dead short, cause other parts to melt down, wires to burn through, etc.

Replace them and hit the road!

 

[vertvert]

Good catch. Electrolytic capacitor failures are probably 90% of modern electronic failures. The insulation between the plates is literally nothing more than a oxide layer on aluminum foil. When these caps fail, they can cause a dead short, cause other parts to melt down, wires to burn through, etc.

Replace them and hit the road!

Alex you have mail.

Op, nice find. Almost every A9L I have opened has issues with the caps. However some had no symptoms and some the replacement didn't address the symptoms. Anyhow goodluck!!

 

[88lx50]

I had that issue with an A9P and soldered in new capacitors. Worked fine after that.

 

[MustangStudFarm]

I am worried that there is a short that caused the ECM failure! At the same time, I really dont have a parasitic drain on the battery? Unlike my '95GT I can leave the battery hooked up in my '93 for a couple of weeks without it getting drained.

Sorry about before man. I realized that I was being a dumb-ass...

 

[MustangStudFarm]

By the way, the only reman unit that I could find was through Summit and it was Cardone brand... I think that there is a Moates QuarterHorse Rep that will solder new capacitors for $50. I opted for the reman unit for $130 and I have to wait until 2/14 for the ship date.

 

[88lx50]

I am worried that there is a short that caused the ECM failure! At the same time, I really dont have a parasitic drain on the battery? Unlike my '95GT I can leave the battery hooked up in my '93 for a couple of weeks without it getting drained.

Sorry about before man. I realized that I was being a dumb-ass...

The capacitors just get old and burn out. Don't buy a rebuilt computer until you give it a try with the new capacitors. It will only set you back a few bucks. Look at the number on the capacitors and go online and buy a couple of new ones.

 

[jmardlin]

I replaced all 3 capacitors in my 93 Cobra computer. The one along the side that is bad on yours was bad on mine and caused erratic MAF voltage. I ordered them frome here http://www.mouser.com/. You would need 2 of this one 647-UPM1C470MDD and 1 of this one 647-UPM1J100MDD.

 

[Cutlass327]

Has this issue been known to cause battery drain when parked? Ever since my 5.0ho swap in my Jeep the battery is dead within a week if parked. Never did that before.

78 CJ5 with a 86 5.0HO, DX3 ECU from 88 Mark VII

 

[tommybunz]

What types of issues were you going through with the car? Maybe I can keep an eye out for them.

 

[Huskinhano1]

That's a good catch! I use to do some electronics work so I can appreciate your find. I've found drawings showing electrolytic being installed backwards. They're cheap to make and the wax doesn't run out when they get warm. I believe that was a big problem Bendix EFI installed in some of the 50's cars.

 

[MustangStudFarm]

What types of issues were you going through with the car? Maybe I can keep an eye out for them.

Hard start, reference voltage was off on a few sensors, ECM would not communicate with a OBD scanner. It was all over the place really. It let me drive it to the gas station, but when I turned the car off it didnt want to start back up. I really ran crappy the entire time!

This is a video that I found. This guy is desperate, so dont let it rub off lol... I was having the exact same problems! Skip to 1min and 2:15

 

[tommybunz]

Ook not really what I'm seeing but I'll check my Ecuador anyways

 

[tommybunz]

Ecu* sorry iPhone auto correct

 

[MustangStudFarm]

Ook not really what I'm seeing but I'll check my Ecuador anyways

Yeah, you can visually check the problem if you know what you are looking for. This video is much better and he shows you how to fix it also.

 

[MustangStudFarm]

Same thing, just a different guy... The first guy is kind of monotone but I think that would be the guy that I would trust with computer parts lol!!!

 

[jmardlin]

When installing the capacitors on a FOX ecu the round spot on the board where it goes is negative and the square spot is positive.

 

[jmardlin]

That bottom video is not a fox body ecm by the looks of it while the top appears to be the same. I went and watched both yeah bottom one is a truck computer but the same principle and the top one you can see is an A9P.

 

[MustangStudFarm]

I replaced all 3 capacitors in my 93 Cobra computer. The one along the side that is bad on yours was bad on mine and caused erratic MAF voltage. I ordered them frome here http://www.mouser.com/. You would need 2 of this one 647-UPM1C470MDD and 1 of this one 647-UPM1J100MDD.

Thanks for listing the part#!!! I talked to Summit today and they pushed the back-oder another 2 weeks. So, I decided that it is time to get a soldering kit!!! I am making a shopping list from Amazon and the electronic store. I hope that these tools will be good enough because I will not use these much. It is $75 for everything listed...

https://www.amazon.com/Weller-WLC10...&qid=1486788237&sr=1-1&keywords=Weller+WLC100

https://www.amazon.com/gp/product/B01ESUKNXG/ref=ox_sc_act_title_3?ie=UTF8&psc=1&smid=A13PRKMVKLJGWH

https://www.amazon.com/gp/product/B00068IJPO/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A1UMBRA5ZTBCX8

http://www.mouser.com/Search/Produc...DDvirtualkey64700000virtualkey647-UPM1J100MDD

http://www.mouser.com/Search/Produc...DDvirtualkey64700000virtualkey647-UPM1C470MDD

 

[jmardlin]

Thanks for listing the part#!!! I talked to Summit today and they pushed the back-oder another 2 weeks. So, I decided that it is time to get a soldering kit!!! I am making a shopping list from Amazon and the electronic store. I hope that these tools will be good enough because I will not use these much. It is $75 for everything listed...

https://www.amazon.com/Weller-WLC10...&qid=1486788237&sr=1-1&keywords=Weller+WLC100

https://www.amazon.com/gp/product/B01ESUKNXG/ref=ox_sc_act_title_3?ie=UTF8&psc=1&smid=A13PRKMVKLJGWH

https://www.amazon.com/gp/product/B00068IJPO/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A1UMBRA5ZTBCX8

http://www.mouser.com/Search/Produc...DDvirtualkey64700000virtualkey647-UPM1J100MDD

http://www.mouser.com/Search/Produc...DDvirtualkey64700000virtualkey647-UPM1C470MDD

The only thing I see is that with the solder you should be using lead free for it. You also will need some flux. Personally I would get the soldering iron, solder and flux if you don't have them from a local hardware store. I doubt they would have desoldering braid or wick though.