truck shutting off

[buddy]

Where exactly is the PCM fuse located on the 1996 Suburban? The diagram shows you the ECMB fuse is the constant power and the ECM1 fuse is the ignition power. They are under the hood as far as I know, but I don't have any OBDII trucks to verify.

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? They do not add 2 circuits, one of the fuses will be the fuse you remove that protects the original circuit. For example, you take the ECM1 fuse out, plug in the "add a circuit" thing and put the ECM1 20A into the "add a circuit" bottom spot. Put a switched battery power line to the 16 ga wire and another 20A fuse in the "add a circuit" and it will work as a parallel power source. Even though its only rated for 10amps, doesnt mean its going to cook. I cannot imagine anything drawing more than 10 amps continuously, maybe just on startup, with glows and what not. I had an electric water pump that only used 5 amps and had more flow than even our HO pumps. I realized though they have regular ones and mini-fuse ones, so probably need regular sized one. Although here is another option that won't be current limited, can just use existing fuses and is also quick, clean and simple http://www.amazon.com/dp/B000CQBNFI/?tag=jhuntlink-20. You can probably find these things at autozone.

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?
Diagram shows you the pin number and wire colors, there is black/white and tan/white, but you would probably want to pull the connector off anyway to check that the pins have good continuity to ground

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?
I just use a knife and cut away a little spot of insulation and wrap and twist a wire around it, I solder if its permanent, and wrap it with electrical tape. Or you can get a butt connector, cut the wire, strip the ends, crimp one end down with one of the cut wire and the other end with the other and an extra wire, but then the butt connector has to fit two wires, if the other end wont be tight with only one wire, just strip it back far enough to fold it over.

My reply is in blue above

 

[Burning oil]

No, don't think it would. I would still temp bypass it as its so easy to do.
My input was directed more to dkanderson though.

 

[jrsavoie]

I can't see the pics from the manual well enough to make heads or tails of them.

Are there any better pics or links to pics or diagrams of G200, G201 or G202 ?

More gnd stuff here from our Tech Ref Library http://www.thetruckstop.us/forum/showthread.php?14596-6.5-grounds

 

[jrsavoie]

I believe he and I are both having WTS ghost issues. I understood the description of his symptoms correctly. Otherwise I would not have horned in on his thread.

If I am wrong I will start posting on my own thread. Please advise.

No, don't think it would. I would still temp bypass it as its so easy to do.
My input was directed more to dkanderson though.

 

[Burning oil]

I don't know. Just tring to offer up a possible issue. After 2 pages of reading I get lost, let alone 7. At one point I was thinking fuel delivery issue too.

 

[jrsavoie]

Confirm or correct please.

I would want to run a fused wire to C11 and C12 joined together?

Attach a T wire to each C11 And C12 and connect the T wires to the auxillary feed from the fuse located in the under hood fuse panel?

Thanks So much for all the help so far.

 

[buddy]

Well, sort of, that would work, but instead of explaining it, I drew a picture of what I recommend. I would test continuity on the lines between the fuses and the PCM. If you dont know how to test for continuity just ask. I think this is the simplest, quickest, cleanest method to test the ignition switch as the source of a problem, by simply bypassing it if the truck wont start. If this doesnt get you a glow light and a SES light then the problem is not the ignition switch or anything before it. Providing power to the PMD and ESO is just so the truck runs, if you are just troubleshooting the ignition switch and PCM power you dont need that.


with most of my troubleshooting I assume a certain level of electical circuit understanding, which is necessary for troubleshooting vehicles. For those that don't understand them it would be good to do some research and come up to speed on some basic terms and what it means such as the word circuit itself, open circuit, completed circuit, parallel vs series, source vs load, continuity, and how resistance measurements are taken. For continuity, depending on the length of wire, you never want more than 1 ohm of resistance from one end to the other. For short stuff should be near zero resistance, but you want some kind or reading and not an open circuit which could be called overload on a digital multimeter.

 

[jrsavoie]

Would there be an easy way to rig up power to C11 & C12 with a relay?

I'm tired of chasing this and would like parellel, key on power.

I will do this test first though.

The problem is so irregular that I have thought it fixed many times only to have problems again 6 monthes later. I have never found anything I could put my finger on and say this is it.

I have suspicions that the problem may have to do with the alarm system that was removed shortly before I got thje vehicle. I've found other remnants that had to be fixed over the years

On my 96 Suburban I installed a GM ignition switch last spring so I doubt that is the problem but it could very possibly narrow down some bad related wiring. & we have all bought brand new parts that were bad before.

 

[buddy]

The problem is knowing if you have a good ignition source to use for the relay coil. In your case I would provide the new spliced in grounds and if the problem never come back great, but if problem does come back then the switch on the power side can tell you if it pre-fuse or post-fuse wiring issue. If you know you have ignition power to the accesories when the problem happens, like the radio always works when you are having the issue then you can use that ignition source to trigger the relay for parellel ignition power to the PCM.

 

[jrsavoie]

Seems the radio and blower motor always work when the vehicle is having issues.

 

[dkanderson]

Wow you guys have been blowing up this post lol its good tho more info more me.

I will be heading back to NC in the morning we are making a stop for a day so we wont be back for 3 days, the vans done great but ive been sick the whole time ive been here but oh well, i will be working on the truck when i get home and still having that guy come over to run some test on it and try and find out what it is cuz im starting to miss my truck.

nothing like hearing that turbo in the morning....

 

[Brooklyn Tow]

Ah!.......Ghost appeared today after about 1 1/2 years.....I was driving all day (no trouble) then came to a corner and after about 4-5 seconds, OFF, like someone turned the key off......I look at my dash all the regular lights are on, so I switch the key OFF, then ON.....Guess what?........NO WTS light.

Get out, open the hood and shake the wire harness where the 2 manifold stud grounds are, go back to the cab, turn the ignition to ON, NO WTS light.

Go back under the hood and wiggle (gently) the wire(s) where they go in (Attach/crimped) to the eyelets, go back to the cab,.....switch the ignition ON and, WTS FLASH'S ON for 1/2 sec and the rig started right up!

Need to install new eyelets with crimp and solder clean the stud and be OK?

It's always those grounds at the manifold stud!........Mine look and feel fine, but obviously not good enough.

 

[dkanderson]

Started the truck today ran for about 30 mins and cut off then started right back up and ran for about 10 mins then i shut it off, i havent drove the truck any where cuz im scared of it shuting off in front of a semi lol, i looked at a cummins turbo diesel that i like but its only 2 wheel drive. i hope to get this truck fixed soon the guy said he would try and get to it next week, so we'll see i guess

 

[buddy]

Any PCM controlled truck with an electrical problem can leave you dead on the road or stranded, could be a day off the production line or 10 years down the road. Unfortunately electrical circuits and testing them is not something commonly taught or learned outside of some vocational or bachelors programs.

 

[dkanderson]

yeah and i dont have the text lights n all that good stuff to test all that crap maybe one day i will, i am going to get me a little scanner to keep in the truck with me all the time but i havent found one i like yet.

i posted this over on diesel bombers to see if they had anymore in put ill take all i can get.