I swapped a 5.3 - 4L60E into my vehicle, purchased a standalone harness which comes with a fuse block with a couple relays and a couple fuses. My question is i thought i had everything wired in correctly and i went to go see if the ignition works along with lights and etc and nothing came on. i can jump a hot wire to the fuel pump wire and that turns on and that is about it. i was told i would only need to wire about 3 or 4 wires from the c207 connector under the passenger side dash and boom thats it.

-also does anybody have the c207 and c100 layout for a 86 iroc z? i can find everything BUT the layout for a 1986. Thanks

 

Did you keep the original wiring that came from the c100? The big ring terminals go to the big stud on the starter. Those terminals power the inside of the car

 

Yup theres wires on the c100 to hook up to power the car. Not many but a few. Check Austin thirdgen website they have 87 c100 which should be close

 

Thanks for the replies fellas. Unfortunately, the c100 has been cutt off from the firewall sside, it is still mounted, just none of the wires are coming out. When i asked my friend who had done a swap very similar he said none of the wires would be needed so i guess that was a mistake. One i figure out which wires are for what, is anyone able to tell me exactly which wires i would need to wire in and to what in order for this thing to have be turn key ready? I thought it was my battery which had only 5v that was maybe not allowing the vehicle to turn on any lights or ignition. Thanks

 

I guess it depends on how you do the swap but starting with an original efi thirdgen i keep the factory fuse box and c100.

On my last holley hp efi conversion i used only a few of the wires. Big purple for starter. Big pink which feeds power to ignition or in my case my ls1 coil pack harnesses. Big red one to starter battery connector for powering the fuse box and interior. Fuel pump wire to holley pcm control or for lsx guys it can go to the 0411 pcm fuel pump control. Tach wire to ecm as well. So something like that, very minimal. Oil pressure sensor and coolant temp for factory gauges.

I reused my two wire alternator so the alt subharness is one big wire to starter and one exciter wire tothe c207 under pass side dash to feed dash light i believe and trigger alt to charge.

 

If you crawl under the dash, follow the wires to the now cut C100 and find the red wires. There should be two. I just looked at mine yesterday to trace wires and the large red wires in the engine compartment are not large red under the dash. You should be able to run a jumper to these wires. You would run power to these red wires to power the car plus power the harness. Under the dash, you should find the pink and purple which will go to the new harness. Sounds like your problem is larger then finding the three main wires. Unless you changing you dash and using the signals from the computer, you need to find the wires that go to the sensors, like water temp, oil pressure, alternator, reverse lights, etc. The other half of the C100 has the headlights, parking lights, wipers, etc. Basically, if you C100 has been cut, you got your work cut out (literally) for you.

 

Was just digging under the dash. There is indeed a third larger Red wire under there going to the C100. Find this if you need to run power to the fuse panel. Basically, you need to run power to all three red wires under the dash.

 

I apologize for the couple months late response. But I ended up getting it squared away with the c100 with help of you guys and some research. The car is a blast to drive and have had tons of compliments on it and it's not even cleaned up! Lots of stuff to do yet but it all comes with time. Thanks for the help along the way!

 

I cannot recall on here who posted this diagram, but this is what I am running with the standalone harness, 0411 pcm. I hope this picture is a helpful reference to anyone who may need it or comes across problems I had while searching for the 86 pinout.

 

Holy smokes, i just noticed this post was form 2019. So il give a quick recap. I got the engine and trans mounted in the car in 2019, lost motivation to keep working on it but didnt wanna sell it. During that time period Mice chewed on the interior, interior wiring, and engine wiring. Early this summer i decided to get the car running, i removed all the wiring in the passenger side fender. None of it was needed in the end. the c100 was chopped off a couple inches from the firewall and I found which wires were needed and not needed. I purchased a new harness, got that wired up and noticed the car wouldnt go into gear when i got it running. Took the trans out and stuffed it in about 3 times making sure everything is good. I determined after researching that i blew the trans pump on start up, due to incorrect TC and flywheel spacing. While inspecting the spacing, i noticed that the flywheel has high and low spots. The flywheel was warped/ bent. Purchased a new one, purchased a monster transmission, stuffed it back in with the correct spacing and everything works now. Wanted to keep the original dash gauges but too much work was needed to have them working and also be accurate with readings. I opted for the dakota digital dash and never looked back on it.

Morale of the story... Try not to just let a project sit for years. Or you might lose touch with the vehicle, what was done, what was not done, what it needs, whats what etc.