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truck shutting off

jrsavoie said:
When your truck dies does it take some time before the wait to start light comes on?

Are you having wait to start GHost problems?

How many times do you hit the key before the wait to start light comes on?

Or do you just wait a minute or 2 and everything goes normally for a restart?
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When it first started it would shut down and i would turn the key off and back on and no glows and i couldnt hear the lift pump but if i waited 2 or 3 mins i would turn the key on and the glows would come on and i would hear the pump and it would fire right, Now it takes almost 5 mins to restart.

when u go to restart it when it shuts down its like it dont have fire like a gas motor would if there was no spark i dont know if that helps.

the guy that was coming out to look at the truck said he would come tomorrow with his scanner and we will drive the truck till it shuts down, he couldnt come today cuz theres 8" of snow on the ground and it wouldnt be fun with the truck shutting down and no brakes lol
 
Oh come on. Have a little sense of adventure.

Watch for the Wait to Start light.

On our 96 Suburban when it is having it's problem you can in the key 1 to 100 times. When the wait ti Start light comes on everything will be as it should.
I've thought I had it fixed several times and always within about 6 monthes it does it again

I tried the ignition switch last go round. It worked for about 6 monthes.
 
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jrsavoie said:
Oh come on. Have a little sense of adventure.

Watch for the Wait to Start light.

On our 96 Suburban when it is having it's problem you can in the key 1 to 100 times. When the wait ti Start light comes on everything will be as it should.
I've thought I had it fixed several times and always within about 6 monthes it does it again
Click to expand...

Maybe its you ign switch i was kinda thinking that maybe thats whats wrong with mine but i dont know lol im kind of fed up with the truck, i started on getting the van ready for this trip i just want to have a good trip and then when i get back ill rip in to the truck like a bat outta hell, less this guy tomorrow tells me what it is but i dont think he will cuz this trucks got a mind of its own.
 
Your problems are being caused by power to the PCM, as in its not getting any so it dies and wont start. You have an ignition switch problem, or a wire shorting problem, or a bad fuse contacts issue. Perhaps you have a corroded wire problem that when it heats up it loses continuity. Or the ground wire could be a problem. the PCM uses the one that goes to the back of the passenger head. The DLC may use the same ground, so try checking the resistance between pin 5 on the DLC connector and chassis ground.

If you dont get a glow plug light or the SES light no reason to even crank. Check to see if you have a glow plug wire shorting to the engine or anything like that.
 
buddy said:
Your problems are being caused by power to the PCM, as in its not getting any so it dies and wont start. You have an ignition switch problem, or a wire shorting problem, or a bad fuse contacts issue. Perhaps you have a corroded wire problem that when it heats up it loses continuity. Or the ground wire could be a problem. the PCM uses the one that goes to the back of the passenger head. The DLC may use the same ground, so try checking the resistance between pin 5 on the DLC connector and chassis ground.

If you dont get a glow plug light or the SES light no reason to even crank. Check to see if you have a glow plug wire shorting to the engine or anything like that.
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Ok i gave the guy that is coming tomorrow the link to this and see if he can get some info off it im just sick of working on the truck, if i cant get it fixed soon i may just take a lose and sell it....
 
IIRC wasnt there a year of chevy trucks (gas or diesel) that the engine bay fuse block would get a bad case of gang green in it???? I don't remember what year(s) it was though.
 
I would get a new GM ignition switch installed. It may not be the problem but. It's about do anyway if it's never been done.

I've done all of mine except the 94. I don't think the older switches were as problematic.

This is not a good part to go aftermarket. Though there may be aftermarket switches that are as good or better than OEM.
 
Well the guy is coming to look at the truck tomorrow, i started it today and it started up on the 2nt try and ran great i let it run for about 30 mins and it didnt cut off and then i shut it off and restarted it about 10 mins later, like i said mind of its own but ill have this guy look at it and hopfully he can find out what the deal is and get the damn thing fixed, we are leaving friday at 4 in the morning and we will be taking my van so hopfully we have a good trip and when i get back ill see what i need to do about the truck.
 
jrsavoie said:
I beliebve he is having WTS ghost issues as apposed to OMD issues.
Thw WTS light does not come on when it does not start. When the light comes on it starts every time.
Please correct me if I'm wrong
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That is right, the WTS light will flash and after that it starts everytime.

and im not sure if the PMD harnes is ext or not kind of hard to see down in there, ill try n get a look
 
You could run a switch from battery to the PCM so you know its getting power, and you could even change the ground too. So you know that the PCM has proper power since that is the problem most likely. Attached is the PCM connector pinout, so you could just supply your own new wires to it if you wanted. Or make sure what you have is good. You can see where the ground for the PCM is, on the back of the passenger head. If you want full size picture files PM me your email address.

OBDII_PCM-ground G104.jpgOBDII_PCM-power and ground.jpgOBDII_PCM_connector-Blue.jpg
 
I beliebve he is having WTS ghost issues as apposed to OMD issues.
Thw WTS light does not come on when it does not start. When the light comes on it starts every time.
Please correct me if I'm wrong
]
Click to expand...





Grounds on the rear pass intake manifold stud, remove, inspect eyelet connections, (change if necessary) clean up the studs (wire brush) and reattach.

Then go thru every other ground on the truck......tech ref library has detailed pics and explanation of which ground does what.
 
Sorry to be an idiot, but could you give me more detailed instructions.

I assume I need to tap into the orange and pink wires for power.

On looking further I am suspecting that I should only access the pink wire as the orange should be hot all the time.

I should add a fuse and a switch to each wire?

Where is the best place to access these wires and make a connection adding power?

Is there a way to tap in a relay and make this connection permanent? Or would that be inadvisable?

Same questions on the ground except about the relay and fuses.

I would want to attach to the black and black with white stripe wires?

G104 goes to the manifold stud.

Where does G200 go?
 
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If I were to tap into the wires I would do it behind the glove box, but you can test the line resistance between the fuse panel and the PCM connector and if thats good you can just do it at the fuse panel. I think you could just use a couple of these things
http://www.amazon.com/dp/B001QRSBW0/?tag=jhuntlink-20

Instead of adding a load though you could add a switched power source. You could add it to both the constant battery power fuse and the ignition source fuse. So then when it dies and doesnt get the glow light or SES light, flip one of the switches and if it works you found out which power source is bad.

To test resistance you can jumper two of the power pins of the PCM, like C12 and C13 then remove the two fuses and test across the load side. There should be very low resistance, less than 1 ohm.

For the ground, I would just tap into it behind the glove box, dont need to cut it, just trim the insulation and splice in a wire and run it to any ground. I dont know if GM put it to the engine for a reason, but its all connected. Chassis ground should have the same grounding capability and same noise on it. You could put a switch on the ground too if your goal is to determine what the problem is. The switch that makes the glow and SES light work reveals the problem.

Youll notice that the PCM has redundant wires for power and grounds, either for redundancy or for current distribution. If you tap in at the fuse there is nothing to worry about with that.

G200 is behind left hand side of the instrument panel, below Fuse Block
 
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Someone allready said, but it would be worth the 5 minutes to try and bypass the PMD ext cable.
Remove the heat sink w/pmd and plug it back into original connector. (Are all the wires in your ext cable black in color?)
Good luck.
 
Where exactly is the PCM fuse located on the 1996 Suburban?

The pictured add a circuit in your link. Is it the correct size? 10 amps, 16 ga wire? They had on with 2 fuses to add 2 circuits.
Do these still yield a fused connection to the fuse they replaced?

For the ground I am looking for the black wire out of the PCM plug correct or could there be more than one ground wire? The black with white stripe?

Advice on stripping the wire to T in a connection. I've never liked scotch connectors because they often cut some of the wires when they are installed. Do they make something similar that works good? That doesn't present that issue?

My usual method of making a T connection is to strip about 1" of wire, fold it over and use a butt splice or a Buchanon to attch the wire.

Would there be room for this method under the dash?

http://www.thetruckstop.us/forum/showthread.php?4357-Wire-Splicing-Basics&p=323480#post323480

buddy said:
If I were to tap into the wires I would do it behind the glove box, but you can test the line resistance between the fuse panel and the PCM connector and if thats good you can just do it at the fuse panel. I think you could just use a couple of these things
http://www.amazon.com/dp/B001QRSBW0/?tag=jhuntlink-20

Instead of adding a load though you could add a switched power source. You could add it to both the constant battery power fuse and the ignition source fuse. So then when it dies and doesnt get the glow light or SES light, flip one of the switches and if it works you found out which power source is bad.

To test resistance you can jumper two of the power pins of the PCM, like C12 and C13 then remove the two fuses and test across the load side. There should be very low resistance, less than 1 ohm.

For the ground, I would just tap into it behind the glove box, dont need to cut it, just trim the insulation and splice in a wire and run it to any ground. I dont know if GM put it to the engine for a reason, but its all connected. Chassis ground should have the same grounding capability and same noise on it. You could put a switch on the ground too if your goal is to determine what the problem is. The switch that makes the glow and SES light work reveals the problem.

Youll notice that the PCM has redundant wires for power and grounds, either for redundancy or for current distribution. If you tap in at the fuse there is nothing to worry about with that.

G200 is behind left hand side of the instrument panel, below Fuse Block
Click to expand...
 
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Would a bad cable yield the Wait to Start Ghost problem?

I have always assumed that the Ghost would not be instigated by a bad extension cable.

I'll let you know on cable color.

Burning oil said:
Someone allready said, but it would be worth the 5 minutes to try and bypass the PMD ext cable.
Remove the heat sink w/pmd and plug it back into original connector. (Are all the wires in your ext cable black in color?)
Good luck.
Click to expand...
 
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