where do I start
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
In the beginning, the positive cable leading from the battery got hot!! and the truck would not crank. I changed out the battery. It fired the motor for two days and then the truck would not crank. The old battery showed 12.7 after charging but it would not start the truck start and less than 12 volts recharging is now in process. I think the voltage regulator is bad any ideas can this be the short.
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?
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 13
From: Sand Lake, MI
it is beginning to get beyond my experience. Tracing grey/red line better known as VREF 26 seems impossible everything is bundled. There is a place on the drivers side firewall were all the wiring seems to separate going through a disk shaped wiring separator of some sort. Question about pcm's location. center of truck behind dash? can it be taken out without disconnecting . no i did not heat up the truck reference 61 66 64 the truck was in park 81 82 85 unknown at this time.
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.
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Freshman User
Joined: Oct 2007
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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.
. 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.
Lead Driver
Joined: Aug 2006
Posts: 5,670
Likes: 13
From: Sand Lake, MI
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.
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Brett Foote
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
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.
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
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Freshman User
Joined: Oct 2007
Posts: 27
Likes: 0
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.
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Freshman User
Joined: Oct 2007
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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?
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
The ECT is in the upper left of this photo (location is basically the same for a 5.8L):
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
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.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
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?
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.