Melting System Ground Wire!

[DWCaprice2017]

Hi, Everyone!
I have an '84 Caprice with a 305.
For months, I've not driven the car except to move it for street-cleaning days due to smelling burning plastic, and seeing a whisp of smoke coming from the rear of the engine once the engine warmed up--but I couldn't locate the source. Yesterday, as I looked at how much stuff I'd need to pull off to remove the left valve cover (to replace the slowly seeping gasket), I saw that the two Ground System wires at the rear of the engine were bare--the insulation had melted--this must have been the cause of the burning smell and smoke. I found a small piece of wiring loom around the wires, I figure the loom eventually deteriorated, letting the wires touch the block. The bolt that the wires attach to, I guess on the bell housing (near the trans dipstick tube), is nearly impossible to get at, so I figure I'd just splice in new wire and attach it onto a ring terminal, securing that on an easier engine bolt, maybe on a bracket.
How does this sound?

Also, as I'm intending to keep the car for awhile--getting it almost five years ago--I'm trying to find detailed diagrams of the wire routing--not the nearly indecipherable schematics in the rear of the 1984 Chevrolet Shop Manual ST-329-54 that I got from a CD-Rom, there's no drawing of the rear of the engine where the System Ground wires attach, for example.
In the attached photos, I'm using a pencil eraser to point.

 

[scoti]

Hi, Everyone!
I have an '84 Caprice with a 305.
For months, I've not driven the car except to move it for street-cleaning days due to smelling burning plastic, and seeing a whisp of smoke coming from the rear of the engine once the engine warmed up--but I couldn't locate the source. Yesterday, as I looked at how much stuff I'd need to pull off to remove the left valve cover (to replace the slowly seeping gasket), I saw that the two Ground System wires at the rear of the engine were bare--the insulation had melted--this must have been the cause of the burning smell and smoke. I found a small piece of wiring loom around the wires, I figure the loom eventually deteriorated, letting the wires touch the block. The bolt that the wires attach to, I guess on the bell housing (near the trans dipstick tube), is nearly impossible to get at, so I figure I'd just splice in new wire and attach it onto a ring terminal, securing that on an easier engine bolt, maybe on a bracket.
How does this sound?

Also, as I'm intending to keep the car for awhile--getting it almost five years ago--I'm trying to find detailed diagrams of the wire routing--not the nearly indecipherable schematics in the rear of the 1984 Chevrolet Shop Manual ST-329-54 that I got from a CD-Rom, there's no drawing of the rear of the engine where the System Ground wires attach, for example.
In the attached photos, I'm using a pencil eraser to point.

You need to trace those wires & determine their origin. Once that detective work has been done, answers will/should be available.

 

[ELCAM]

I don't think that is a ground wire(s) looks like it might be the electric choke wires.

The pic that says "wires attach here" can you clean that up some?

 

[383_StealthRam]

Ditto on the "clean up the wires/loom some" to get a better idea what your looking at, it's hard to tell from pics.

It might not be exact for your model/year but maybe close, some wiring diagrams can be found here:

A/G BODY WIRING DIAGRAMS - MalibuRacing.com

Special thanks to Cliff (AKA 81classic) for all the diagrams!

maliburacing.com

Looks like you have/had some critters living under your hood nibbling on your wires. All the fuzzy stuff is probably from nesting?

 

[Ernest]

I agree totally with everyone here.... thoroughly wash that engine bay so we, but especially you can see whats going on so you can deal with the issue at hand beforte you have an accidental fire.

 

[DWCaprice2017]

scoti, ELCAM, 383_StealthRam, Ernest,
Thank you all for your responses!
I tried to clean that bolt where the wires attach--not easy to do. I tried scratching off
dirt with a screwdriver, nothing came off, after I used engine degreaser spray.

I didn't see any signs of a critter having nibbled the wires.

The electric choke wire goes to another area.
--------------------------------------
What I hadn't said in my original post is that the engine has
an electronic QuadraJet, and that I live in California--the car
may have different emission parts in 1984.

I have a new mystery--I'll post this on the main page also.
The first photo below is the EGR valve. In all of my searching, I've not seen any replacement EGR valve
that looks like this--with two vacuum ports. Is this OEM for the car? As can be seen in the second
photo, there's a hex screw that apparently holds the EGR onto the base.

When I removed the hose from what I think is the exhaust gas recirculation solenoid valve that connects
to the EGR valve (see engine photo), a little carbon came out of the hose. I've been trying to find a replacement
EGR solenoid, figuring that it might be full of carbon, but I can't find the part.

I did discover that the hose that connects to the side tube of the EGR valve was poorly fitting, surely
causing a vacuum leak--likely all of the hoses need to be replaced!

With the EGR Valve off the engine, I'm taking it to a mechanic to use a hand vacuum pump on
it to see if the diaphragm is still good. I'll likely replace the EGR valve anyway, which brand is
recommended?

Thank you for the help!
Bye,
Daniel

 

[scoti]

scoti, ELCAM, 383_StealthRam, Ernest,
Thank you all for your responses!
I tried to clean that bolt where the wires attach--not easy to do. I tried scratching off
dirt with a screwdriver, nothing came off, after I used engine degreaser spray.

I didn't see any signs of a critter having nibbled the wires.

The electric choke wire goes to another area.
--------------------------------------
What I hadn't said in my original post is that the engine has
an electronic QuadraJet, and that I live in California--the car
may have different emission parts in 1984.

I have a new mystery--I'll post this on the main page also.
The first photo below is the EGR valve. In all of my searching, I've not seen any replacement EGR valve
that looks like this--with two vacuum ports. Is this OEM for the car? As can be seen in the second
photo, there's a hex screw that apparently holds the EGR onto the base.

When I removed the hose from what I think is the exhaust gas recirculation solenoid valve that connects
to the EGR valve (see engine photo), a little carbon came out of the hose. I've been trying to find a replacement
EGR solenoid, figuring that it might be full of carbon, but I can't find the part.

I did discover that the hose that connects to the side tube of the EGR valve was poorly fitting, surely
causing a vacuum leak--likely all of the hoses need to be replaced!

With the EGR Valve off the engine, I'm taking it to a mechanic to use a hand vacuum pump on
it to see if the diaphragm is still good. I'll likely replace the EGR valve anyway, which brand is
recommended?

Thank you for the help!
Bye,
Daniel

Your comment above in bold...... Absolutely!

My Malibu has 52k on the clock. It had the original 47k mile 305 drivetrain w/era underhood hardware when I purchased it. I did a basic ownership tune-up (fresh dist cap, plug wires, plugs, valve cover gaskets, oil change, timing tweaks etc. I went over all of the 'era equipment' replacing hoses & such. It ran good enough that I was ok w/it for being a basically untouched 47k 305 (it got the job done). Fast forward to December 2023 & I needed a sbc for a flipper project & decided the 52k 305 was the ticket. During the swap, everything 'era correct' under the hood was removed as it was no longer in the correct vehicle. NIGHT & DAY difference in how it ran. All of those mandated items were not functioning correctly & there were likely multiple vacuum leaks. The set-up ran much better in the new vehicle vs. how it did for the few years i drove it 'stock'.

 

[abbey castro]

Hi, Everyone!
I have an '84 Caprice with a 305.
For months, I've not driven the car except to move it for street-cleaning days due to smelling burning plastic, and seeing a whisp of smoke coming from the rear of the engine once the engine warmed up--but I couldn't locate the source. Yesterday, as I looked at how much stuff I'd need to pull off to remove the left valve cover (to replace the slowly seeping gasket), I saw that the two Ground System wires at the rear of the engine were bare--the insulation had melted--this must have been the cause of the burning smell and smoke. I found a small piece of wiring loom around the wires, I figure the loom eventually deteriorated, letting the wires touch the block. The bolt that the wires attach to, I guess on the bell housing (near the trans dipstick tube), is nearly impossible to get at, so I figure I'd just splice in new wire and attach it onto a ring terminal, securing that on an easier engine bolt, maybe on a bracket.
How does this sound?

Also, as I'm intending to keep the car for awhile--getting it almost five years ago--I'm trying to find detailed diagrams of the wire routing--not the nearly indecipherable schematics in the rear of the 1984 Chevrolet Shop Manual ST-329-54 that I got from a CD-Rom, there's no drawing of the rear of the engine where the System Ground wires attach, for example.
In the attached photos, I'm using a pencil eraser to point.

1st item is to wash the area so that colors can be seen. A ground wire touching bare metal is of no concern. That what its suppose to do. You can attach it anywhere that you can get to. 2nd is the wires that are NOT ground wires. Those will be hot with current/signal depending the function. .