Capacitors for ECM Computer
 

94 2.3l 2wd XLT

Hello.

In the next step of trying to get the thing running, it has been suggested that the capacitors in the ECM almost always go bad. Not being electronically minded, I think I have identified two capacitors, but am not sure if there are more. I'm posting a photo of the board and then a photo of what I'm asking about. The two circled in red I believe are caps, but I'm not sure of the things that are circled in turquoise.

Thanks.
https://cimg9.ibsrv.net/gimg/www.ran...7a5bd570e8.jpg
https://cimg8.ibsrv.net/gimg/www.ran...e424616fc8.jpg

YUP, the two in red a capacitors.
Obvious signs of a failed cap is swelling on the ends and/or bulging sides.
Check the solder on the circuit board too, it should be nice shiny, not powdery and corroded, it can fail from heat.

I would be guessing somewhat about the others, but one looks like a diode and the other yellow ones I think are another type of capacitor, but it's the others in red that fail.

Clean the contacts, both male and female of the big plug that goes into the brain box, any slight corrosion there will cause problems.
Make sure the ground wire for the box is clean, Ford put green paint on them.

+1 ^^^

The two in red circles are the Capacitors that fail, its a 20+ year thing, they were not "bad parts" just can't last as long as the other components in this application
Write down the values on each, i.e. 47uF 63v
Also which side is "negative", has the "-" on that side, new one has to be oriented the same way

What is the best way to clean the contacts? Especially the female plug?

Google "Contact Cleaner".

I was envisioning tiny brushes and magnifying glasses.

So that's what Google is for!

Ok, I'm dense. :pat:

Thanks.

Don't beat yourself up too much, there are very tiny brushes available for the job.
I've also used pipe cleaners as well, but they have a tendency to leave fuzz behind, so I use my compressor to deal with that.
The brushes help the contact cleaner do it's job.
This is just one example, electronic supply stores will some, as well as automotive stores, hardware stores, etc.
Amazon will probably have endless supplies of them.

Electrical Female Plug Contact Cleaner Brush and Anti-corrosion Kit | Specialty Tools Product | MercedesSource.com

So I was wondering why one can plan on these capacitors to fail. Then I was looking at the specs on the ones I ordered and it said a life of 2000 hours. So, an average of 45 mph makes 90,000 miles. Just about when these fail, mine being a little over 100k.

It's more like 20,000 hours for this type of capacitor, before they start to leak or corrode, generally they last 20 years or so in vehicle applications
I am sure 2,000-5,000 hours would be manufacturers spec because they have to warranty it for worse conditions, i.e. high temperature use at max voltage rating

I had to order caps on eBay. The old ones physically look ok. I'm not going to take them off until the new ones arrive. And if and when my soldering iron gets delivered. Just looked at package tracking and it said it was delivered to a place 250 miles away. Yesterday. Ugh!