I doubt if that is the short. A hot battery cable indicates a huge current draw or the cable/connector is bad. If the voltage is really low to the PCM, then perhaps that is the reason why VREF is in the toilet.

I know the '92 and later PCMs cannot be removed without taking off the cable connector. It's not a big deal to do it. I suggest you disconnect the battery before doing so. Bill, aka subford, has said he has removed the connector without disconnecting the battery many times over, but I am a pessimist why tempt fate?

 

Sorry about that, yea I said grey-red it'd be brn-wht wire and you might not have to chase it down least not at first.

First try simply unplugging each sensor shares that ref voltage, if one is the problem, it drawing that circuit down for some reason if unplugged the value should return to normal.

Connect your meter to the Brn-Wht wire and then unplug the,

EGR position sensor

throttle position sensor

map sensor

Does the meter read .5v? if so reconnect each one in turn until voltage drops back down, when/if it does that one be the problem.

If the ref voltage doesn't read .5v with all sensors unplugged then there is a problem in the wire itself or in the PCM or its connection to it.

The act of unplugging the computer and reconnecting it might correct the issue/s, its connections corroded but hard to say without more detailed history on truck. Say its been in water up to its head lights before problems started for example.

 

.5v ? VREF is rated at 5.00 VDC +/- about .25 VDC.

 

Oops yep 5 volts not half a volt!

 

first, I would like to say thank you for sticking with me on this adventure. so let me understand your instructions. each of the named sensors should have a brown and white wire connection and each sensor's b/w wire should display a 5 volt value at koeo. We know that the map sensor is pulling only .03 volts. if I disconnect the other sensors and the value of the MAP sensor returns to 5 volts then the other named sensors, or connector or wiring or PCM is bad, correct? the beast ran fine at arrival and has not been in deep water since I have had it.It does have a speedometer and tach fluctuation because of having larger tires. but I'll pull and check the connection. I should have said starter solenoid instead of voltage regulator, my bad. . The meter shows continuity 12 volts within the cable and the connection. I am asking you out of ignorance. There is a great many wires running to the same pole as where the battery connection is made. There is only one wire that goes to the small threaded top middle plug, one large cable going to the starter and none on the bottom threaded small post. Is that the proper wiring? I will find the PCM this morning and look at the connectors. I was looking in the wrong place for the PCM . The picture help a great deal. I do not know what all the parts are or do and seeing them makes it easier to learn.

 

This might help you out:

courtesy of FordFuelInjection.com

You can see the VREF (pin 26) wire is BR/W, Brown/White.

 

I pulled the pcm cover off and there was green on the upper or top of several male terminals. I bushed it off with a paint brush. how should I clean the female end?

 

Yup the green as you know is bad and is likely the problem, get can of electronics contact cleaner, and flush the connector until both are clean then allow it few minutes to dry.

Then apply light coat of dielectric grease to the plug before reconnecting it to protect it from corroding again.

Don't over do it with it little goes a long way. What I do is spread thin layer over the harness connector side so as to lightly cover all pin holes. Then when plug in the PCM, all its pins get a light coat of it on em on the way in.

 

What he said

 

the PCM female side has two parts. One is the cover with the bolt and 4 hold down straps and it covers or almost covers the wiring running through the second part which contains the female wire connection setup. Do I have to remove or separate the cover from the back of the female board so I can flush it from the back through the female connector, the bolt doesn't seem to want to pass through the body of the female connector or can I spray the face of the female connector. The cleaner I have is for cleaning MAF. it states that it will not harm. I'll has to get some dielectric grease asap.

 

where is the etc sensor located on the 5.8l .I warmed the truck for 10 minutes with no movement of temp gauge.

 

I traced down two of the three brown and white wires. koeo showed voltage at the map to be .05v and what I think is the egr, it is stacked on top of a pipe coming from the exhaust manifold and contains a brown and white wire it showed koeo zero Volts. I tested the b/w wire from the egr with engine running and got .98volts. I am left with no thought than the ecc is bad. any other thoughts?

 

The ECT, Engine Coolant Temperature, sensor is not related to the temperature gauge in the dash. Two different sensors.

The ECT is in the upper left of this photo (location is basically the same for a 5.8L):

 

You need to remove the connector from the PCM itself to effectively clean it out.

 

Until you get the connector off the PCM and clean it, it is anyone's guess based on the "green stuff" you stated you saw on the connector before.