1991 Explorer EB won't idle.

[Bahnburner]

I'm helping out a friend who has a 1991 EB explorer that's running like crap.
Here's the codes on the 4.0-liter engine:
112 ACT sensor less than self test minimum of .02v
117 ECT sensor less than self test minimum of .2v
122 TPS circuit below minimum .6v (tested sensor--good)
157 MAF sensor went below .4v during last 80 warmup cycles
513 Failure in EEC processor internal voltage
556 Fuel pump circuit failure
565 Canister purge circuit failure
566 3-4 shift solenoid failure
629 Converter clutch control circuit failure

I cleaned and verified operation of the IAB valve and solenoid. I also checked the TPS sensor manually for resistance and it was really good. I also manually checked the voltage from the TPS harness and it was indeed low (nowhere near 5v). It seems as if the EEC which feeds voltage to all the sensors is wreaking havoc here...could it be a bad ground to the EEC? Where is the EEC? Where is the ground to it? Any other leads or ideas? If I haven't given you a piece of info you need, let me know...I'm fairly good with this stuff and should be able to relay good info for your recommendations.

 

[BrooklynBay]

Welcome to this forum! Did you see if the alternator is charging properly? Did you clean the battery terminals? Check the PCM relay socket to see how much voltage is in there. Maybe the problem is in the PCM relay not making good contact.

 

[Bahnburner]

You mean the EEC relay socket? The EEC relay is in the covered passenger side compartment with other relays/fuses. I can check that.

 

[Bahnburner]

I checked voltage to the EEC relay...a good 12 volts. I also swapped in a standard relay with the same result too. Put a battery charger on the battery and still got only .3v on the TPS sensor, indicating that the EEC isn't letting the sensor get the 5v it should have. Makes me think its a bad ground on the EEC?

 

[BrooklynBay]

Check the ground wires near the battery, and the fuse for corrosion.