wiring mess...please help!
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
wiring mess...please help!
hey everyone. first post here. just traded an eclipse for a 88 Camaro.
more and more research on the car I realized it was originally a v6 auto car and they put a carbed 305 5spd in it.
the wiring is bothering me. I pulled the harness out of the engine bay because they hacked the hell out of it and I had loose wires and connectors everywhere.
can anyone help me out with figuring out which wires I actually need? do I even need the ecm under the dash where its carbed? the car has the a/c delete pulley on it so I don't need the wires for the a/c either.
I want to make the wiring as basic as can be in the engine bay. (alt starter coil) just enough to make it run
more and more research on the car I realized it was originally a v6 auto car and they put a carbed 305 5spd in it.
the wiring is bothering me. I pulled the harness out of the engine bay because they hacked the hell out of it and I had loose wires and connectors everywhere.
can anyone help me out with figuring out which wires I actually need? do I even need the ecm under the dash where its carbed? the car has the a/c delete pulley on it so I don't need the wires for the a/c either.
I want to make the wiring as basic as can be in the engine bay. (alt starter coil) just enough to make it run
Member
Joined: Dec 2013
Posts: 175
Likes: 1
From: Scottsdale, AZ
Engine: 350-TPI
Transmission: 700-R4
Axle/Gears: 3.27 Posi
Re: wiring mess...please help!
In your shoes, I would mark every loose connector and remove it from the wiring harness. Unplug the harness from the firewall/fusebox and trace the unconnected wires back to the plug. You can remove/cut those wires. If I were you, I'd remove the wire and connector from the harness plug in case you decide there is some accessory you want restored. Regarding the ECM, you don't need it. You already have a non-ecm distributor and carb, so you could remove the ECM and associated wiring. It will take you some time to figure it all out. It wouldn't hurt to have the service manual so you have wiring diagrams handy. Your factory cruise control, if the car had it, won't work since that's tied to the ECM. Judging by the picture, it looks like most of the stock wiring is gone, so how much do you really have left to work on?
Re: wiring mess...please help!
Ditch that air cleaner ASAP. They are appealing for hood clearance, but are prone to burst into flames. 1-1/2" drop base 14 x 3 works well.
you will also need something like this http://www.summitracing.com/parts/edl-8126
you will also need something like this http://www.summitracing.com/parts/edl-8126
Last edited by Joe Tag; May 23, 2014 at 08:39 PM.
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
all the factory wiring was still there...it was just ziptied around the starter. there was a couple wires I was unsure of but as long as I have the starter alternator and dist wires that's all that matters to me. I can figure out the rest. I took out the a/c box and im trying to figure out a clean way of bypassing the heater core. I need to figure out the gauges and all that too. I got confused when cutting the wires because theres so many spliced wires going from the ecm harness to the firewall harness. im hoping I didn't screw anything up lol.
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
i already planned on ditching the air filter, not sure which one i wanna go with yet. and i already bought the single line feed its just not on in the pic. it has the fuel pump mounted on the drivers fender im trying to figure out where i can put that to clean it up too
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
and whats the best way of wiring in the electric choke? the po had it wired into the alt wire and the ground was run all the way to behind the passenger headlight
Member
Joined: Dec 2013
Posts: 175
Likes: 1
From: Scottsdale, AZ
Engine: 350-TPI
Transmission: 700-R4
Axle/Gears: 3.27 Posi
Re: wiring mess...please help!
At a minimum, your electric choke needs 12v switched from the key. Ideally, the 12v should only power the choke coil when the engine is running. That way they choke coil doesn't start heating up right away. Here's one way to do it.
http://classicoldsmobile.com/forums/...ke-wiring.html
http://classicoldsmobile.com/forums/...ke-wiring.html
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Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
putting the harness back in im still confused on a couple things. after removing the ecm part of the harness I have a bunch of random tan wires that go nowhere. what are they for? and im not sure how to hook up the coil now that the ecm wires are gone too
Member
Joined: Dec 2013
Posts: 175
Likes: 1
From: Scottsdale, AZ
Engine: 350-TPI
Transmission: 700-R4
Axle/Gears: 3.27 Posi
Re: wiring mess...please help!
Without wiring diagrams, you are going to have a very tough time figuring it all out. I believe The tan wires are associated with the ECM-controlled ignition, which you no longer have. The coil needs 12v switched from the column that stays active when the key is turned. Most hot-in-run wires will lose power when the engine is cranking, so they won't work for a coil. You have a running car, it sounds like your coil wire is fine.
If your coil wire was part of a harness you removed, it needs to go back. Bottom line, whatever you do, the coil wire needs to have 12v in run AND while cranking.
Also keep in mind that removing the wiring harnesses means that you may have holes in the firewall that will allow heat/fumes into the passenger compartment. I would check those ASAP. You don't want to risk CO getting to you!
If your coil wire was part of a harness you removed, it needs to go back. Bottom line, whatever you do, the coil wire needs to have 12v in run AND while cranking.
Also keep in mind that removing the wiring harnesses means that you may have holes in the firewall that will allow heat/fumes into the passenger compartment. I would check those ASAP. You don't want to risk CO getting to you!
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
i figured out how to wire in the coil, and the electronic choke. now the issue is fuel delivery. it has a mr gasket pump on the fender, does that mean that the intank pump is already taken care of or do I need to wire in another relay
Member
Joined: Dec 2013
Posts: 175
Likes: 1
From: Scottsdale, AZ
Engine: 350-TPI
Transmission: 700-R4
Axle/Gears: 3.27 Posi
Re: wiring mess...please help!
If you have a low-pressure pump, you don't need to worry about the one in the tank or its wiring. Is it working properly? The previous owner may have rerouted the wiring to the new pump.
Re: wiring mess...please help!
How to strip all the old EFi stuff off your harness
https://www.thirdgen.org/forums/ltx-...p-3rd-gen.html
Body pinouts to see what you need to keep
https://www.thirdgen.org/forums/ltx-...formation.html
In a nut shell, you need all the wires from the C100 and a handful from the C207/C221
C207 D if retaining an in-tank pump
M if retaining stock gauges
C221 C if using electric fan(s)
If using none of those, then ALL the wiring for the pass side can go away
Power/gauges go through the C100. The EFI system fuse points go through the C207/221
https://www.thirdgen.org/forums/ltx-...p-3rd-gen.html
Body pinouts to see what you need to keep
https://www.thirdgen.org/forums/ltx-...formation.html
In a nut shell, you need all the wires from the C100 and a handful from the C207/C221
C207 D if retaining an in-tank pump
M if retaining stock gauges
C221 C if using electric fan(s)
If using none of those, then ALL the wiring for the pass side can go away
Power/gauges go through the C100. The EFI system fuse points go through the C207/221
Thread Starter
Junior Member
Joined: May 2014
Posts: 11
Likes: 0
From: providence ri
Car: 1988
Engine: 305
Transmission: 5 spd
Re: wiring mess...please help!
all I want to use is the stock gauges but I can rewire all them myself. im pretty sure ive figured everything out
Supreme Member

Joined: May 2005
Posts: 1,058
Likes: 4
From: Malvern, Arkansas
Car: 90 IROC 2-92 Zs blk vert & prpl
Engine: stealth ram brodix track 1 ful port
Transmission: 700r4 4l80e
Axle/Gears: iroc 375 lokr 92 Z 277 pos vert 327
Re: wiring mess...please help!
Buy a book for your car and get the electrical diagram and learn it. Find another car like yours (stock) with all the wiring intact and make notes and take pictures. Going back EFI would be a great way to go and since the factory TPI is gone you could buy a HSR, a decent street cam, fix the A/C and have a great daily driver that gets decent gas mileage.
Supreme Member
Joined: Jun 2011
Posts: 2,036
Likes: 6
From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
Re: wiring mess...please help!
Without wiring diagrams, you are going to have a very tough time figuring it all out. I believe The tan wires are associated with the ECM-controlled ignition, which you no longer have. The coil needs 12v switched from the column that stays active when the key is turned. Most hot-in-run wires will lose power when the engine is cranking, so they won't work for a coil. You have a running car, it sounds like your coil wire is fine.
If your coil wire was part of a harness you removed, it needs to go back. Bottom line, whatever you do, the coil wire needs to have 12v in run AND while cranking.
Also keep in mind that removing the wiring harnesses means that you may have holes in the firewall that will allow heat/fumes into the passenger compartment. I would check those ASAP. You don't want to risk CO getting to you!
If your coil wire was part of a harness you removed, it needs to go back. Bottom line, whatever you do, the coil wire needs to have 12v in run AND while cranking.
Also keep in mind that removing the wiring harnesses means that you may have holes in the firewall that will allow heat/fumes into the passenger compartment. I would check those ASAP. You don't want to risk CO getting to you!
Supreme Member

Joined: May 2005
Posts: 1,058
Likes: 4
From: Malvern, Arkansas
Car: 90 IROC 2-92 Zs blk vert & prpl
Engine: stealth ram brodix track 1 ful port
Transmission: 700r4 4l80e
Axle/Gears: iroc 375 lokr 92 Z 277 pos vert 327
Re: wiring mess...please help!
You can fix it. It is just a learning curve like anything else. I took my 89 IROC from mass air flow to speed density. I bought a SD harness from a 91 trans am and dash harness from a 91 Z28. I had to add air bags and a lot of stuff I wasn't counting on but I bought a book and dealt with one wire at a time. My car looks like a factory 90 model IROC now complete with new 90-92 dash and 90-92 gauges and working air bag. It was a 6 month chore but really all you have to do is find a good harness from a wrecked car. One of the guys on here probably has one they will sell you.
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