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Just bought a 6.2 - can you identify what's missing?

T

tvguy

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I just picked up an '82 K30 yesterday with a 6.2 diesel. Let me say up front that I know NOTHING about diesels. The guy I bought it from said the engine was "blown" and that's all he knew. I spent some time today giving it the once-over, just to see what kind of shape it was in. I hooked a battery up, and initially, the only thing that worked were the headlights and the horn. After doing some tracing, I figured out the the relay on the driver's side fender wasn't working. I was able to jump the relay, and got some more of the interior stuff to come on.

While looking it over, I noticed that there was something missing on the firewall, and that 3 large red wires from the factory harness had been cut. Can anyone tell me what's missing from the firewall, and perhaps what the large red wires might go to?

.jpg
 
Well i'm guessing it's just a conjunction box of some sort :dunno:

truck002.jpg


Someone else might chime in with the real purpose of it
 
Thanks for the pic. It makes a little more sense, but I have no idea why someone would remove it?
 
No idea. The wires themslves i think go to the starter :dunno: or alternator. That'd be my guess.
 
Those missing wires to the junction block on the firewall is the cause of most of your electrical problems inside the cab.

Though it varies from truck to truck, most of them have a thick red wire that runs from the starter up to that junction block, then has one wire that runs down to the fuse block, and another wire that runs up to the big post on the back of the alternator.

The wire that runs to your junction block is a main power feeder, and having it cut like that will wipe out most of your electrical system.

The connector on the firewall I have no idea about. My new 86 GMC has the same connector with nothing in it.
 
It seems clear from Randy72982's picture that the cut wire from the blower motor clearly goes to this junction block. Would it be reasonable to assume that the other 3 cut red wires also go to this?

Anybody got one of these junction blocks laying around they'd like to sell?
 
Your definitly missing the junction block... I don't normally save them when I part out a truck or I'd send you one for free. Every 73-87 Chevy truck has one though, gas or diesel. So it will be fairly easy to find in the junk yard.
 
Awesome! I didn't know they came in the gas trucks too. I'll head to one of the local junk yards and see what I can find. Thanks!
 
I believe that's actually called the "fusible link", not really a junction block because normally there is just one wire in, one wire out and just serves as a big fuse in the main power line to the fuse block.

Again, not sure why they would chop it out of the system unless something was screwy and it blew it out (but that usually points to a serious electrical problem) or stole it for another vehicle.

But as already mentioned, this is the cause of most of the electrical issues.
 
The fusible link is the wire that is supposed to go to the junction box. Looks to me like he's missing both.
 
AJMBLAZER said:
The fusible link is the wire that is supposed to go to the junction box. Looks to me like he's missing both.
Click to expand...

Correct. I bought a junction block from Classic Parts. I also bought some fusible link wire and connected the cut wires to the junction block. The fan, interior lights and the relay on the driver's fenderwell are all working now. I tried cranking it on Saturday, but the starter was dead. I replaced the starter, installed it, turned the engine over for a minute or so then heard a loud grinding sound. Upon inspection, one of the starter bolts had stripped and fallen out. I'm going to have to put a helicoil in, and have read that I need to find and install the starter support bracket. I hope to get all that done and try to crank it again this weekend . . .
 
Just for future reference, you want to replace the starter bolts whenever you replace the starter, for the $6 it'll cost you at the dealership it's worth it. Whether it's the extra torque required to crank a diesel or just that they stretch and weaken over time, broken starter bolts are pretty common on these engines and treating them as single use items saves a lot of headache . . .
 
Wrench said:
Just for future reference, you want to replace the starter bolts whenever you replace the starter, for the $6 it'll cost you at the dealership it's worth it. Whether it's the extra torque required to crank a diesel or just that they stretch and weaken over time, broken starter bolts are pretty common on these engines and treating them as single use items saves a lot of headache . . .
Click to expand...

Went by the dealer today and picked up the starter bolts. One OBVIOUS problem is that the bolts the previous owner had installed were 3/8", when the correct ones should be 10 x 1.5 mm. I had to pick up a different helicoil kit since I was sizing by the 3/8" bolts that were in there. The dealer didn't have the support brace, but I went ahead and ordered it . . . it was only like $3.
 
Last time I picked up a "blown" 6.2L it had a broken starter bolt... replaced the bolts and starter brace and it ran for another year without a hitch. Then the crank snapped...
 
Randy92782 said:
Well i'm guessing it's just a conjunction box of some sort :dunno:

truck002.jpg


Someone else might chime in with the real purpose of it
Click to expand...
Thanks for the info, you know whats scarry, my 82 K30 that I'm working on is the same exact color !!!
 
Definately a factory color. It's actually my dad's old work truck when he worked in St. Louis but i got it now. They pretty much kept good up keep on it other than it WAS a work truck so it's alotta rough :haha:

It's an 83 GMC 3/4 ton 4x4. Here's a pic

 
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