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So....
I worked through most of the issues on the new to me 87 C4.
Car runs and drives and is overall in good shape.
Biggest problem is the wiring though and I will need some advice how to get started.
Two pics that pretty much describe it...
Melted and bare wires almost falling out
Wire melted and basically just falls apart upon touch.
Now imagine half of the other connectors look like that, or the wires like the one you see on the old tach filter.
Touch something and it just crumbles.
One of my issues is that I am still learning what is what (relay) and the engine bay being so cramped doesn't help.
The manual I have is not very useful and the wiring diagrams are not the best.
Right now I am thinking about pulling the harness and go over it entirely off the car. This would make it easier to just access everything and do the job right.
The engine bay wiring is mostly melted, the inside wiring is mostly hacked. A wonder the car still drives. Someone installed a push button, but the wiring is almost dangerous, power wires are not insulated etc.
Any thoughts about pulling everything? I read it can be done with engine in place but the harness does not disconnect at firewall and has to be pulled though and disconnected on inside?
I don't mind fixing a harness myself, have wired several motorcycles from scratch, but was wondering if anyone has used a rebuild service? My biggest concern is wires breaking off a relay or somewhere else and I wouldn't know what order they were in, if that makes sense.
Last but not least, and this might be a weird question but I have not been able to find an answer to:
Does a Corvette in general start/turn off differently than any other stick shift car or is it just mine?
Reason I am asking: right now I have to put the key in and turn on ignition. Key doesn't start the car. For that I have to press a push button.
When turning off the car, I can do so by turning the key to off, but I am not able to remove it. I have to put the car in reverse (and only reverse) first before it allows me to turn the key fully to off and remove it. Is that normal (the key removal)?
And I definitely want to get rid of that silly push button and go back to a regular key turn on.
Plus I don't want to park in reverse gear in order to remove the key from ignition.
I burnt out a fuseable link to the radiator fan on my 86 because the motor was screwed and was drawing too much current.
id say you have that going on here but it seems like its on a much bigger scale.
the tac wire.....is the voltage from the dizzy somehow leaking into that wire? you must have a short somewhere and are feeding 12v straight at max amps to do all that damage.
Tach didn't work before but now is. Just swapped the tach filter this morning.
Then I set the timing. Challenge there was to disconnect that one connector without braking it. The hot wire was also in pretty bad shape.
The wire that goes from push button to starter was melted and hot wire just in the open. The tach filter wire going to distributor was melted into other wires it crossed.
So yes, difference things going on, but probably all starting with heat. And when connecting battery it sparks pretty good, so another sign something is not right.
Current plan is to remove as much from engine bay as possible, check everything, remove harness and redo. Wrap in insulating material and route away from heat sources or moving objects. Fun...
Really amazing this car still runs and drives.
But I'm glad it's parked and not on the road. It's not safe with wiring like that. And you don't even want to see the under dash wiring. I was looking for the asdl and could not even find it. Just a lot of cut wires everywhere...
My advice, for what it's worth, would be to find someone who's parting out an 87 and buy the wiring harness. These things run
on electronics and bad wiring will be a headache as long as you own it!
Does this 87 have the 4+3 manual? If so, having to put the transmission in reverse to remove the key is normal. Both my 85 and 76 have manuals and have to be put in reverse to remove the key from the ignition.
Yes, manual. Ok, good to know that putting it in reverse a corvette thing.
And yes, tires are bad, I'm fully aware. Good catch. She will get new shoes once the wiring is sorted.
I looked at replacement harnesses but am a bit confused as to what I need, especially what years would fit.
there is also a T connector near the distributor with one (vaccum?) line going down somewhere. That's completely dissolved as well. Have to figure out where that is supposed to plug in, unless it's just a drain, but I doubt it.
and looks like my previously posted answer disappeared. .. the tachometer was not working before but now is after I put in the new tach filter.
I'm still puzzled that this car runs and everything works with this wiring.
battery sparks when connecting the negative pole, so definitely something is up.
could this just be an issue of grounds? Maybe the majority of your grounds are corroded and the voltage asked to go somewhere so it’s traveling places it’s not supposed to and melting things. Personally, from my limited experience, I would not replace the wiring harness that’s a huge effort. If you have portions of wires that are melted, I would grafting new wiring using a soldering gun and heat shrink tubing and go from there. It goes without saying that you must find the reason for the massive voltage over wires Causing them to melt
I'm sure the reason is exposed wires due to heat.
i need to at least pull the engine bay harness. There are hidden wiring issues that I can't even see right now, like the one I found behind distributor.
Need to pull so I can remove some of the original insulation to give me more clear wire to work with. I have pigtails already but can't solder them on because there is just not enough good wire accessible..
There is also a lot of yellow stuff all over. My guess is dried up fuel that wasn't cleaned up.
Someone put in an Edelbrock air plenum but probably didn't know what they were doing.
Tps was way off (caused check engine light but now sorted) so was engine timing. So I'd rather pull everything, remove as much as possible to give her a good cleanup and start wire routing from scratch.Cant trust previous owners.
Does this 87 have the 4+3 manual? If so, having to put the transmission in reverse to remove the key is normal. Both my 85 and 76 have manuals and have to be put in reverse to remove the key from the ignition.
Interesting. I do not on my 87 4+3. Wonder if something if broke?
there is also a T connector near the distributor with one (vaccum?) line going down somewhere. That's completely dissolved as well. Have to figure out where that is supposed to plug in, unless it's just a drain, but I doubt it.
.
It's definitely a vacuum line. Maybe someone can chime in on where it goes but needs fixed.
I began to write last night that the damage on the tach filter was caused by an external fire, and not an electrical over-load (short). I didn't put it up.
But the "yellow stuff" comment confirms that your car had a fire. The yellow stuff is fire extinguisher residue.
he is probably going to need a new wiring harness if available...
I began to write last night that the damage on the tach filter was caused by an external fire, and not an electrical over-load (short). I didn't put it up.
But the "yellow stuff" comment confirms that your car had a fire. The yellow stuff is fire extinguisher residue.
Whoa...
Guess I better pull the battery as soon as I get home...
Are you getting a vampiric power drain? You mentioned sparking when you connect the battery.
I'd use a voltmeter between your battery and wire and see how much voltage is being pulled with the car off, then start pulling fuses until it goes away. That would get you in the ballpark anyway of where the issue is.
Looks like someone who didn't know what they were doing tried to play electrician on this car. Best of luck, I don't envy you the job ahead of you.
Are you getting a vampiric power drain? You mentioned sparking when you connect the battery.
I'd use a voltmeter between your battery and wire and see how much voltage is being pulled with the car off, then start pulling fuses until it goes away. That would get you in the ballpark anyway of where the issue is.
Looks like someone who didn't know what they were doing tried to play electrician on this car. Best of luck, I don't envy you the job ahead of you.
Well yeah, definitely somebody didn't know. Even the spark plugs wires were installed flipped around.
Well, now I definitely want to keep that car. I Iike challenges and it's always great satisfaction to save a vehicle.
Wait until you see what's is going on under the dash. I will take a pic of the mess when I get to it at some point.
I have never seen anything like that...
I'm ok replacing the entire harness, does anybody know what other years would work?
Or maybe if this one would work: https://www.corvettemods.com/C4-Corvette-1985-1989-50L-57L-V8-Painless-Performance-GM-TPI-Harness-w-MAF--Standard-Length_p_21554.html
With connectors like that I used a pencil to separate the wires, cleaned them, and put electrical tape on them. I did that for all
connectors showing wire.
I bought a "Casper's Electronics Weather pack kit" that came with the same connectors GM uses from 1 wire through 8 wire connectors both male and female. They are now sold by Summit for up to 4 wire connectors.
These kits are lifesavers when you are wiring a new accessory or updating the parts in your engine compartment. I used one to replace my A/C Clutch connector. They are very high quality and will outlast my Corvettes. This is the "professional" way to fix or replace old bad connectors. The new wires will not get corroded so quickly in a new weather proof connector.
Having the right tools and right parts make the job so much easier. I have a set for the GM cars and then there is a set made for German "Deutsch Connector Kits" I have as well. Just be sure to have a good wire crimper to use, I like the ratcheting type for good solid crimps.
Decided to just replace everything.
Just spoke to someone who has the complete set for the entire car, bumper to bumper, for $500. It's off an 86 manual.
Does anyone know if that fits? If so I'd be more than happy to spend the weekend replacing everything and end up with a real nice car.
Do you know if your car has an electronically controlled transmission? Somewhere along the line, they went to an electronically controlled transmission that had its own computer.
Car is having a (wiring) meltdown...
