hexibot43 wrote:I just updated my post with the pics
Got 'em- thanks.
I've confirmed that it's the tranny pressure regulator (EPC in the Ford book) that can be disconnected and without its switching spikes, the power lines are almost completely clean, the MAF signal is stable, and the idle is good. The EPC solenoid is in spec at 4 ohms and clicks when manually energized. I haven't checked the pressure, but shifting is harsh while the ckt is open. I thought maybe a snubber diode across the solenoid had opened up, but sticking one on didn't help.
In the meantime, the EVR solenoid has failed shorted so the EGR valve is not operating (can't tell that this is a problem).
-Know what the EEC-IV drive ckt for the EPC solenoid is?
-Know what the duty cycle for the EPC should be at idle? (I subbed in a 1K resistor for the solenoid and got a nice square wave but at a longer period duty cycle, 59% over a period of .8 sec w/engine off)
I'll do some more checking of the power and ground circuits.