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Intake Ground Stud-bolt

No problem. I was confused when looking at the diagrams and you mentioned the Glow Plug fuse, which is like the OBD1 trucks, and I have AllData access for 96 trucks.

Dave had a good suggestion that you might want to check and make sure the Glow PLug signal wire from the PCM to the controller is not shorted to ground. Or the glow controller isnt shorting it out somehow. Maybe if its shorted it causes this issue. I figure that shouldnt cause a problem, because the PCM would have some line protection, but maybe that protection is to shut down. The PCM itself probably puts it to ground when not triggering the controller. So you could disconnect the PCM harness and check those pins to ground, see if you can get a real low resistance reading. If you leave it connected to the controller there will be some resistance to ground, I will go measure it later tonight maybe.

This goes beyond a glow system problem. Its possible the glow circuit has something to do with it. Anyone with a WTS issue might immediately jump to the glow controller, but the real problem is the PCM isnt powering up correctly.
 
I couldn't agree more Buddy, I still think he has a PCM problem since it's effecting other systems as well (STS), however I'd still diagnose the glows since it should be relatively easy to do and not really cost anything.
 
Louis, I changed my GP controller at first when I had this issue. It fixed nothing.
 
On the 96 Suburban the last thing I did was change the ignition switch. It ran fine for 9 monthes, at which poiint I found a bad ground wire.
When I changed the ignition switch that was all I did at that time. I've been trying to resist the urge to check several things at once anymore. Many times I'm not sure if cleaning the grounds for the 10,000 time is what made a difference or the other 3 things I did at the same time. So I try limiting what I do.
 
Update:

Didn't do much in the way of diagnosis, (yet) been a little busy with "work"......But the truck seems to be getting worse. Seems I can get it to start and even drive for a while but, now when I'm at idle for any extended period of time she'll shut down and won't restart for a while.

Also now when in no start condition, "sometimes I can hear/feel in the underhood fuse block, Fuel pump and A/C solenoids "Clicking" away at a pretty good pace......Before this ghost issue started acting up again, last summer I was having climate control issues and was blowing/shorting out head units. Seems the problem was PCM was not giving power to the A/C "low pressure" switch (the switch at the bottle on the firewall)......The temp fix, (which is still there) was to bypass the PCM and a wire was run from the head unit control switch to the A/C lp switch at the bottle.

At that time it was thought that I had a short in the harness that went from PCM to A/C solenoid LP switch, or the underhood fuse block was the problem because sometimes the A/C would go "out" and if I repositioned the A/C solenoid (bad connection) it would come back on..........Hence the story about the "clicking from the fuse block".

Another friend told me that his suburban (gasser) had a bad connection(s) in the underhood fuse block, and heard this was somewhat of a common issue/trouble spot from his electrical repair guy, he ended up pulling the block apart and fixing some internal connections.

Sorry about the, I know a guy, who knows a guy, that has a friend who's uncles brother "said" Bla, Bla, Bla.......

http://www.thetruckstop.us/forum/showthread.php?23575-A-C-thread
 
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So the truck was wrecked. I would look in the damaged areas for a pinched or skinned wire.

Check voltage to the PCM. As the PCM is loosing codes the hot all the time power wire may not be supplying 12v. If it is stop there and replace the PCM for bad memory etc. (If this is the case you also have another issue attempting to set a code causing a complete computer failure.) Also low voltage from the ignition switch will cause havoc with a computer - see frying an Atari game system for good examples. A shorted 5v supply to sensors could also take down a weak supply voltage to the computer.

Grounds are not the complete picture, supply voltage to the computer or bulbs can flicker the light. Computer can't hold the transistor completely "on" to get full brightness from the bulb from lack of voltage. In fact check the ground side of the bulb (wire) for voltage when it is weak and this will point you in the right direction.

Was the compressor shaft bent in the wreck as well? Ever get the AC electrical issue solved?
 
WarWagon said:
So the truck was wrecked. I would look in the damaged areas for a pinched or skinned wire.

Check voltage to the PCM. As the PCM is loosing codes the hot all the time power wire may not be supplying 12v. If it is stop there and replace the PCM for bad memory etc. (If this is the case you also have another issue attempting to set a code causing a complete computer failure.) Also low voltage from the ignition switch will cause havoc with a computer - see frying an Atari game system for good examples. A shorted 5v supply to sensors could also take down a weak supply voltage to the computer.

Grounds are not the complete picture, supply voltage to the computer or bulbs can flicker the light. Computer can't hold the transistor completely "on" to get full brightness from the bulb from lack of voltage. In fact check the ground side of the bulb (wire) for voltage when it is weak and this will point you in the right direction.

Was the compressor shaft bent in the wreck as well? Ever get the AC electrical issue solved?
Click to expand...

Truck was hit in the nose.....Harness and PCM/firewall location is not so close, also this WTS issue was/is for as long as I have owned this truck.

Also, still need to get to the firewall where the harness passes thru to see if any wires are chaffed/broken.....I've been all over the harness at the top rear of engine compartment, where evrything seems to be OK.

As for the A/C, the compressor has been changed and the low pressure bypass wire is still as is.......The underhood fuse block has got me thinking ("Clicking").....But again this issue was present before all these other problems with the accident, A/C, etc.....
 
If the wiring has been traced that well.
Pins backing out - easy to spot on the computer connector.

Otherwise your computer runs fine till it tries to set a code or enter the damaged area and locks up. Messing with the ground resets it. Verify voltage to the computer then replace it. They are only like $88.00 exchange.

We had one do this to us on an olds. Ran fine till it failed the ignition knock sensor test. Turned on the light on and went into limp mode. It would not store a code. Replaced computer and problem continued. Swapped ign module out - still had an issue. Found oil between knock sensor wire and connector opening the circuit. Took all damn summer. Bad computer, bad knock sensor, and connector. Ign module was fine.

For grins disconnect the low side AC switch that you bypassed as it may be shorted to ground. Test it.
 
For grins disconnect the low side AC switch that you bypassed as it may be shorted to ground. Test it.
Click to expand...

Need to ID the wire in the harness or at the PCM for the LP switch or A/C command or however it works (I'm far from a wiring Guru)......From what was explained to me, PCM commands the LP switch......As for the control heads shorting out, I'ts still a mystery.


Otherwise your computer runs fine till it tries to set a code or enter the damaged area and locks up. Messing with the ground resets it.
Click to expand...

NO, Works like this:........My SES light is on because there is a boost code that has not been cleared (P1656).....When the ghost appears, PCM dies, Ghost leaves, truck starts, NO SES, drive the truck and the code shows up, and/or (1656 not repaired yet)..... key off and when go to start (key on, start) SES is back.
 
Update:

when the truck shuts down the GP controller is NOT getting power (Yellow wire)......Now I don't know if PCM is dropping out, Ign switch is bad, or harness is pooched between the the GP controller and the PCM.

I am SO NOT the Electrical engineer!.........Maybe process of elimination?
 
Ok, so here is my suggestion.

Take some scotchlocks and tap the power wires from the PCM, and setup the switched ones on a switch and the constant to the battery. Do the same for the ground. If it isn't working, hook them up one at a time and check to see if that solves the problem. That will essentially eliminate a power an ground issue and help to determine if the PCM has failed or not.
 
OK....New problem, sitting in the yard with my mechanic friend....Truck is running, PCM hanging out the dash.....We're waiting for the truck to shut down to probe C3 to see if there is power at the PCM, or something like that.....He's in the pass seat, I'm walking/standing in and out of the office, doing my routine.....Anyway truck is still running as I'm walking back and I see BROWN coolant dripping from behind the pass side wheel.

I yell out, What the F%$# is leaking now!.....I run too the truck to see coolant coming from the overflobottlele tube, I ask him "whats the temp gauge read!".....He says about 3/4.............I flipped out!......and yelled, "TURN OFF THE TRUCK!

Now I filled this truck with PEAK full strength coolant after the collision (6 months ago)......about equal parts water and coolant, I bled the system and did the little refill as needed.....SO I Know the coolant was green and a new radiator to go with it!

Well, from what it seemed the t stats must have been closed or the cap was bad (new cap too)......So I take the cap off open the bleeder and Start the truck...... she starts to cool down right away.....coolant (Brown) starts flowing and she's hovering at 185*-195*. The Bleeder screw has air and coolant coming out like crazy......So whats this, Busted head gasket blowing into the antifreeze?...........Oil is black, no sludge/milky oil at all......Can this brown antifreeze have been in the block? If it was how did I miss it when I filled and bled it?

I'm still trying to figure out what happened.....Truck hasn't left the yard in a week, only idling for WTS ghost diagnosis.......So whats 3/4 on the temp gauge....235*-240*?

It's like a bad dream!
 
I have seen the brown stuff show up after a n overheat issue on all kinds of engines not just 6.5's. seems "boil" the block and all kinds of gunk comes out. It might not be a crack or blown gasket but a bad thermostat on this on. either way she needs flusshed out.
 
Which way is the flow?.....Whats the direction to Flush?.....Clean water in thru the ________ and flush till it comes out clean at the _________ ??


But, what happened?......How could have the system "locked up"...........and why after I opened the bleader and the overflow bottle, the flow returned to normal?......Bad cap, air lock, and the 2 stats.......are'nt they designed to fail open?
 
Started the truck up "cold" this morn........upper hose was soft, but still don't know if there was any damage from that overheat.

Truck sounds like a bad pully spinning, wonder if my waterpump is biting the dust.

Still need to flush out the brown "Garbage" in there, can anyone advise me as to the direction of "flow"...........maybe remove the top rad hose and stick the garden hose in the top of rad.....and let the junk come out the disconnected upper hose.....Or is that backwards?
 
Water comes in from the bottom of the rad into the water pump. From there it goes into the engine block and up through the heads to the water crossover. From there it can go to the heater core(which ends up back at the rad in the end) or through the bypass hose back into the waterpump and is re-circulated through the block until the coolant gets hot enough to "open" the thermostat. Once the thermostat is open then the coolant goes from the water crossover into the upper rad hose and into the radiator. The coolant continues to flow into the radiator until the temperature drops enough so that the thermostat closes. Then repeat the cycle above.
 
So if I feed the overflow bottle line, that comes into the top of the rad and disconnect the upper hose, it should make it thru the whole system.....Is that correct?
 
There's 2 hoses that run to the overflow bottle. One from the top of the rad to the surge tank(overflow bottle) and one from bottom of the surge tank to the bottom rad hose.

I would opt for the hose that goes from the bottom of the surge tank to the bottom rad hose. This way you'll push the coolant through the block and radiator, instead of promarily just the radiator.
 
Ok, I thought the top hose would do it....but the bottom hose will push straight to the bottom of the rad where the waterpump will pick it up and send it thru the block.......and then eventually out the top rad hose on the drivers side.

The top hose would send it in the right direction also, just take a little more time to make it to the WP and thru the block......either or, let it exit thru the top rad hose on the driver side?...........Is that the idea?

And turn on the heat to flow thru the heater core......correct?
 
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