I think I have a bad EEC-4. Is there a way to prove it is bad? This will be my 3nd bad cpu. Original had leaking capacitors at 123,000 mi. 1st replacement from junk yard lasted 300mi, 9 monthsI (learned a lesson there). Last one from Rock –Cardone F4TF-AVA (1994 F-150 5.0 eng. 5 speed Mazda trans) lasted 1300 mi. or 3 years. Ole man here-don’t drive much! LOL. I was coming home in heavy down pour, wipers banging away, Defrost on high, Shifted from 2nd to 3 gear and there was nothing there – it just quit., like I ran out of gas. Turned over ok, so thinking the ¼ tank of gas was wrong I switched tanks. Truck started and got me home the last ½ mi. Once home it would not re-start. Truck was also making a strange noise that day like a horn in the distance that got louder with rpm. Next day it Starts, but runs terrible lots of black smoke. Setup a jumper to check KOEO codes and noticed the fuel pumps (front and rear) would never shut off (sign of a bad EEC-4, but hard to believe). Engine Check light stays on and will not flash any codes. Check light stays on when running too. Pulled the EEC-4 and opened it up, expecting to find water or bad capacitor. Found nothing, looked at circuits with a 4x magnifier and could see no signs of leaking capacitors or breaks in circuits. Used a hair dryer to make sure there was no moisture in the connector, the pins or board. Reinstalled – still the same. Could anything else be causing this problem? What was the distance horn sound as rpm increased? Thanks – lost – need help.

PS I should get volume discounts on ECC-4’s

 

Sounds like a bad PCM to me. There are businesses that can professionally repair these boards but that can cost as much, or more as simply buying another one. I haven't had issues with my Cardone PCM yet. Check to make sure the rubber seal around the PCM connector in the firewall is intact, no rips, and make sure it's seated correctly.

 

Most of what is circulating for cores out there is junk. Nobody can " rebuild" them and the best you can hope for is new caps. That is a job you can easily do yourself.

I would go back to the junkyard. Hopefully you can pick up an unmolested ECM. Put new caps in that and you may have something.

 

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