I Need A New PCM - Any Suggestion?

[Joel Hauser]

My Roadster has been up on jacks since September when it suddenly started runnning rich and misfiring. The engine is from a 1996 GT 4.6L SOHC. It has stock fuel injection and electronic ignition. I have the original key ziptied under the dash, because it has the Ford PATS antitheft system.

After checking all the sensors and grounds, replacing the MAF, and staring at the motor blankly for hours, I have concluded that the PCM must have failed - again. It is actually the 3rd PCM that I have used, and the symptoms I am having now are the same that were fixed a couple thousand miles ago by the second and then the third PCMs I installed.

The PCM was purchased from a refurbisher called Flagship 1. I sent it back to them for warranty replacement two months ago. Unfortunately, they tell me that they haven't been able to locate a working replacement. I believe them. They are still looking, but my fear is it will be years before they find a working 25-30 year old computer/PCM.

Can anyone recommend a source for buying a replacement PCM, or repairing the ones that I have; I still have the first and second PCMs on a shelf? I am hesitant to buy an unrefurbished used one because they don't seem to have the exact same part number. Also, I think I will have to have the PCM programed to the original for VIN. I don't think there is a professional programer within 150 miles of where I live. Also, I don't think this is a programing issue; my sons, who know this kind of stuff, think it is a hardware issue.

Thanks for the input
Joel

[Papa]

This may be an option for you.

https://www.holley.com/products/fuel_systems/fuel_injection/terminator_x/terminator_x_and_x_max_ford_kits/terminator_x_mod_motor_kits/

[Joel Hauser]

Thanks Papa, I just emailed Holley and asked if they make a plug and play version that works with my engine. The Terminator kit costs quite a bit more than I was hoping to spend, but I'll see what Holley has to say.

[Papa]

It looks like these mod motor kits should be pretty much plug & play and use all the original sensors and ignition components. You just need to know if your engine is a 2V or 4V and which injectors you have. There are several videos on YouTube you might want to check out. Going this route may be more expensive, but will get you a modern computer with a ton of support available. I have a Terminator X managing my Inglese 8-stack EFI.

[frankeeski]

Give them a call or send an email. They may have an ECU for your application.

http://www.megasquirtpnp.com/index.php

[Joel Hauser]

I just emailed megasquirt, and Holley last night. Thanks to you and Papa. I didn't know that there were new aftermarket PCMs available. Hopefully they have one that works with the 1996 motor. Unfortunately, what I've found is the 1996 and 1997 motor is not always supported by aftermarket parts suppliers. I'll keep my fingers crossed.
Thanks again.

[GoDadGo]

Here is an off the wall "Dark Side" suggestion...
Ditch the system and install a carb instead.

https://www.summitracing.com/parts/edl-2838/make/ford
https://www.summitracing.com/parts/hly-0-80670
https://www.summitracing.com/parts/msd-6011/make/ford#overview

I saw this done on an early Mustang (1965-ish) with this intake setup at Cruising The Coast.
At first glance I thought the engine was a 427-Cammer Engine.

[Blitzboy54]

I mean for what those kits cost you could just dump the PCM all together and install a sniper. Would need a new intake manifold though I would assume.

[jab351w]

Before spending $$$ on an aftermarket ECU, have you tried opening one of your spares and checking whether the electrolytic caps have leaked? This is a common failure for this vintage of Ford ECUs, and just old electronics in general. If that's the problem the fix is relatively easy (lots of soldering how to videos on YouTube) and the only cost is a for handful of caps (< $10).

The following cover repairing earlier A9L EEC IV, but the same concept applies to the newer ones, though the caps may be surface mount vs. through hole.

https://www.ffcars.com/threads/preemptive-eec-iv-repair-thread.522393/
https://www.stangnet.com/mustang-forums/threads/eec-iv-capacitor-replacement-info.921085/

[Bob Cowan]

I've used a Megasquirt on a couple of cars, and I really like them. Easy to set up and tune, and very durable. This one appears to be a plug and play for your car.

https://www.diyautotune.com/product/ford-mustang-1996-1998-ms3pro-pnp-plug-and-play/

[Dgc333]

Rock Auto has remanufactured PCMs for a little over $100.

[Joel Hauser]

Hey Godadgo, I would love to install a carb, but edlebrock doesn't make an intake manifold for the 1996-98 heads. Also, the conversion is kind of expensive. But believe me, I've thought about it for years. Thanks.

[Joel Hauser]

jab351W, I opened one of them up, but honestly, didn't know what to look for. But this is a good idea. I'll take a look inside them this evening after work.
Thanks
Joel

[Nigel Allen]

Hi Joel,

I searched 1996 ford ecu capacitor replacement. There are you tube clips to guide you and capacitor kits available on line. Hopefully they might help. Maybe you can find someone with electronic experience to help you change the parts. Or grab a soldering iron, a 'solder sucker', plus desolder braid, and learn a new skill. If you choose this route, grab an old printed circuit board from a radio or similar to practise on.
If the capacitor replacement works, it will likely be the cheapest repair you ever will do on your car.

Best of luck,

Nigel.

Edit: whoops, I see jab351 beat me to it !

[jab351w]

jab351W, I opened one of them up, but honestly, didn't know what to look for. But this is a good idea. I'll take a look inside them this evening after work.
Thanks
Joel

There are some pictures of leaking electrolytic caps and more info on the "capacitor plague" (yes, it's a thing) on Wikipedia:

https://en.wikipedia.org/wiki/Capacitor_plague

Caps don't necessarily have to be leaking to be bad, either. If it were me and the ECU were already dead I'd go ahead and replace all of the caps. Best case you fix it, worst case it still doesn't work.

If you built a car from a pile of parts, you can handle replacing a few caps. Seriously, though, let me know if you need more help with the process or identifying suitable replacement parts. Good luck,

Jeff

[Joel Hauser]

I opened up both of my spare PCMs. they each have two capacitors, neither of which is leaking. There is no obvious damage to the board or anything else. Oh well, I ordered new capacitors anyway, they are cheap. Until the parts arrive from China I'll put them back on the shelf. I still haven't decided if I'll order a used one on ebay, a refurbished one from Rockauto, or an after market one from megasquirt or holley. Or just wait to see what flagship 1 comes up with.

[Nigel Allen]

Chinese suppliers are not a good source for electronic components. You are just as likely to get parts as bad as what you are replacing. This is not prejudice, it is from practical experience. Try the following suppliers:

- Mouser.
- RS components
- Element 14 (used to be Farnell)
There may be other suppliers in the US that I am not aware of.

You may have to buy quantities larger then what you want, but the parts are cheap and I'm sure there are other members on the forum that would buy some from you.

If it adds any comfort, capacitors can fail with no visible damage. Heat is certainly an aging factor.


Cheers,
Nigel

[Joel Hauser]

Thanks Nigel, I'll see if I can get the parts from a different source.

[jab351w]

I'll second what Nigel said. I wouldn't suggest buying electronic components from Amazon. Just too many counterfeit parts nowadays. Even passives like caps can be fakes, and it's definitely a big deal for higher-dollar ICs. In addition to the vendors listed (all good), there's also DigiKey (https://www.digikey.com) in the US. You should be able to get small quantities from either them or Mouser.

Also, apologies if you already know this, but electrolytic caps are polarity sensitive. Make note of the markings relative to the leads on the old ones before you remove them, and install the new ones in the same orientation. Assuming they're leaded, the longer lead on the new ones should also indicate positive.