Found The Ecu!!!!and The Problems!!
What an education I've had in the past 2 weeks on EEC-IV
HEy guess what! Computers do go bad.. but usually caused by something else feeding crap back. In my case Bad Wiring.
THe computer is buried in the right front kickpanel and strapped to the metal behind.. 60 wires. plastic capped connector w 10mm hex bolted to ECU HAd to disconnect it to get it down. ORig comp would not do self test. NEw comp (used 35 bucks) had no codes cuz no history but it did self test and ultimately work.
Heres what I found. After 20 different tries. and 2 weeks.
Set out to check ALL leads from ECU plug to sensors. found 3 bad/weak grounds ganged at battery. Cleaned and re terminated THen found a shorted lead to CANP solenoid. Also found intermittent 5 v at TPS and also at IAC solenoid . Plugs to both were not carrying clean so I cleaned terminals and jumpered one. But still not right so I traced wiring back along engine cables.
I Peeled back the factory wrapping and found the OEM Sig return gang splice (3 welded wires) had rubbed its way thru the insulation of the feed wires adjacent to them inside the cable wrap. Then found similar situation with gang splices on distributor wires going thru same area. Sometimes I would have a PIP sometimes not. Checked module and Hall switch in dist to be OK. AS it turned out some ass had caught the cable under the manifold and crushed it against the valve cover along with one engine harness plug!.Over time it just worked its way thru and shorted , at first intermittently, then allthe way thru for good. I thik this is what got the computer too.
I separated all wires taped them off and and re -wrapped. THen I found that the 2 round engine harness plugs weren't carrying signal reliably either (wiggle test. I screwed with them but couldny make them clean so I finally just cut them out completely and but spliced each of the wires together. and shrink wrapoped them. THis eliminated 3 weak areas per wire inthat plug alone. (about 15 wires. CHecked continuity again Finally got nice clean signals on all wires to and from the ECU.
After about 30 hours trial and error finally got a kick. But spenty another 2 days before I figured out that the spark plugs were gas fouled from trying to start so much, and tho I had spark it was a bit yellow, so I checked and found a borderline primary in the coil.
Replaced spark plugs and coil today. VROOOOOM Halla -f'riggin - lu - yahh.!!
Highly recommend Book "FORD FUEL INJECTION& ELECTRONIC ENGINE CONTROL by Charles O PRobst. TElls all tales in great details about 1988 thru 1993 systems.
PRobly saved about 3 grand . Though I dont have much hair left.
Anybody else have this much fun???
