Amillionoh7

iTrader: (1)

Just curious what everyone does with the tbi/tpi harness after doing a carb swap. PICS please

Night rider327

iTrader: (13)

Remove it and sell it to someone that needs it.. Or remove it and put it up in storage for later user if needed

Remove, cut out, get rid of all not needed and trash it.

skinny z

I completely removed my harness and ECM. There was nothing in it that was needed for a carbed computerless installation. I had to add a circuit for the electric choke but that was it. I reconfigured my ignition too but that was more due to the MSD upgrade than anything else. An HEI distributor will work fine.

Amillionoh7

iTrader: (1)

mine is a 92. not sure if that makes a difference. but the wires in the harness go to the alternator and up by the headlights. I don't need any of it?

skinny z

I can't commnet on the differences between your 92 and the 86(s) I've worked on. I can say that in my Camaro, there were two distinct harness'. One handles the lighting and few other under hood functions. That harness came directly from the large bulkhead connector located near the brake booster. The other handled engine management. It exited the engine bay by way of the passenger fender and came into the cabin through the kick panel.
Some of the engine mangement has to be taken care of once the ECM is removed.
Cooling fan control will have to be done via the temp switch in cylinder head and hard wired to a realy.
I'm not sure if your gauges were fed via the computer or not. I went the aftermarket gauge route so that wiring is seperate in my case. Coolant temp and oil pressure in particular.
You'll have to source ignition power for the distributor and carb choke.
I'm not sure what you're doing about a fuel pump but the ECM handles it too. I went to at first a mechanical pump, then to an aftermarket external pump (and back again).
Other than that, I had nothing else to consider.
You'll have to deal with your VATS too. Here's a link:
https://www.thirdgen.org/forums/engi...s-ecm-tpi.html

Amillionoh7

iTrader: (1)

Ok thank you. I already bypassed vats when i was diagnosing a no crank issue last year. i am setting up a Holley red pump tomorrow so when i run the fuel lines i am going to remove the harness.

skinny z

Good luck.
Keep us posted.

Amillionoh7

iTrader: (1)

Ok got it out today. i didn't realize the the plug at the fire wall bulkhead was 2 separate pieces



forgot to get a before pic but here she is

Amillionoh7

iTrader: (1)

still have to find a way to hold the other harness in the bulkhead

skinny z

You'll need both halves of that connector (C100) to run your vehicle circuits other than those controlled by the ECM.
The ECM harness exits the engine bay through the passenger side fender and goes into the cabin through the kick panel. Most of what's in there isn't needed for a carbed application. Like I said, you will have to supply a few additional circuits to make everything run.
I've attached a pinout list for an 88 Camaro. (It's all I have handy at the moment). You can see the circuits that are involved in the harness you'll pulled out although the pinouts won't be the same.

Amillionoh7

iTrader: (1)

Amillionoh7

iTrader: (1)

found this on alldata in case anyone else needs it

skinny z

What year is that for? I understand that some of the C100 connectors are a 1 year only deal. Others cover a a few years in a row.

Amillionoh7

iTrader: (1)

92

skinny z

So, looking at that, you have a number of circuits in the harness you removed that are needed. Obviously the lighting and wipers but also the TCC, tach and VSS (amongst others).
The harness not listed (to the ECM) would have the engine operating functions. TPS, IAT, MAP, etc. Those are what you can discard for a carb swap.
I'm guessing you have this figured out.

mjdavis68

iTrader: (1)

Thank you! i do....

Amillionoh7

iTrader: (1)

Yea. the big half of the connector is transmission and engine wires and the small half i left plugged in is lights and wipers

Amillionoh7

iTrader: (1)

i have a alldata account if anyone needs any other digrams

skinny z

I was pointing out that some of those circuits will be useful with the carb swap. Not sure if you're were intending to abandon them.

makaveli09

I think by 92 that the ecu harness maybe all in one with the rest of the harness.
But its easy to remove.just unplug the ecu from the passenger side. And then take off the wire looming.
And take it apart from the starter and alternator and gauges. Then you can reloom the harness with smaller looming as theres only like 5 or 6 wires left. The wording harness for the headlights remains untouched.

skinny z

The wiring for the engine management has to be somewhere. It's not listed in the C100 connector diagram listed. No IAT, TPS, MAP....Just wondering.

Amillionoh7

iTrader: (1)

here:

Amillionoh7

iTrader: (1)

Also:

wade280

send harness and ecm to me if you dont need it!

TvLover

Just Curious here. but what was that Old wiring for? TBI or TPI?
If its TPI, I may be interested.

skinny z

Thar she blows!
(That's what I was referring to)


So to answer your original question (and it looks like you've figured it out), that's the harness that gets discarded for a carb swap.

Amillionoh7

iTrader: (1)

TBI sorry

racerkilla

I took my stock harness and cut out everything I didn't need. I kept the wires for oil pressure, temp, tach, 12v ignition, starter trip, fan switch and reverse lights. Took awhile as I re run everything to clean it up. Ended up with 2 relays. Fan and fuel pump. I have switches in my ash try to turn fuel pump on and switch to bring my fan on whenever.

Also got rid of the junction piece toward the front passenger side and again soldered and shrink wrapped everything

Minimum amount of wires but still used the factory plug.

Amillionoh7

iTrader: (1)

looks clean. I like it

racerkilla

Thanks, just take your time and don't be in a rush

Another tip for the wiring is if you hook the harness back up you should be able to ground certain wires and it will peg the gauge inside. That is how I figured out the feed wire for each gauge. Then follow the wire all the way to the c100 and leave it. Move onto the next. Makes for a nice clean job.

You will have to hotwire your fuel pump as the ecu use to prime the pump and oil sender over a certain pressure kept pump on. The red test wire on the relay with 12v will turn pump on or you the green with white stripe I think.

For the fans you can use the sensor in the head to the factory relay and will work by ground. Also can t a toggle switch into that wire to make a ground to bring fans on manually.

Sorry for rambling but might help you

Amillionoh7

iTrader: (1)

Yes very helpful. i did switch to a mech. fuel pump so that is one less hassle. what did you do with the speedometer and tach

racerkilla

For the tach I think it was a white off the original coil. Hooked that into my hei

For the speedo I didn't use any of the factory wiring. I have an auto meter speedo. Two wires come off the speed sensor. I grounded one of them to the tunnel and the other went to the back input of my speedo. Autometer is nice because can program the speedo to different rear gears or tire height. You drive 2 miles at 45mph and sets calibration.

TTOP350

iTrader: (8)

Best thing to do is leave them where they are so you can put them back in 6months when you get fed up with the carb

Amillionoh7

iTrader: (1)

One nice thing about living in south Texas is the weather doesn't change much. so the carb'd cars run pretty consistant

jwfirebird

iTrader: (2)

if the engine(carb and timing) is set properly they run fine.they start fine, its people who dont know what they are doing that give the issues. people had carbs on everything for like a hundred years. everywhere, from Alaska to mexico.

tero

Sorry for jumping on here so late. I'm doing a swap also and I wanted to know how did the swap turn out

Amillionoh7

iTrader: (1)

Here check out my other page there is some videos near the end. I still drive the car to work everyday.

https://www.thirdgen.org/forums/carb...carb-swap.html

tero

You used a mechanical fuel pump? Is there a spot on the stock 305 for one? I'm new to camaros do I may ask alot of ???

Amillionoh7

iTrader: (1)

Yes used mech fuel pump. every sbc has a spot for it. but might not have lobe on cam.

tero

I have fuel pressure regulator. I wish I would've knew before hand. Did you have to rewire anything else. I need all the help I can possibly get.

Amillionoh7

iTrader: (1)

depends on what your hooking up. to make it run you only need 2 wires. starter, distributor

tero

Will I have to reroute the fuel pump wires since I'm still using the stock pump

Amillionoh7

iTrader: (1)

No they are on a different harness

smh1987FFB

I see the AC runs through the ECM. IS there a good way to bypass it other then wiring in a switch? I also noticed my car (87' Formula) has what I'm guessing is a switch on the power steering pressure line that runs though the ECM. What is that used for? Low pressure warning light maybe?

Amillionoh7

iTrader: (1)

Not sure as I did not hook ac back up in mine. And I just left the power steering wires disconnected

smh1987FFB

You live in South Texas with no AC? Do you only drive it from 1-5am in the summer?

Amillionoh7

iTrader: (1)

nope just suck it up. Iv only had 2 cars in my life that had ac.

Amillionoh7

iTrader: (1)

And the wife drives them

snakeshooter

Quick question about using manual fuel pump. Did you have to do anything to the stock fuel pump or fuel lines. Other than unplugging the wires to it and hooking the fuel line to the pump?

Twin_Turbo

iTrader: (25)

A handy tip (maybe) for those with a fual pump relay and a toggle switch. There is a much easier/better way to do this. Get a TIMED NO relay, this will close for a set amount of time after triggering the coil with key on. You can have this one trip the main FP relay if you want to keep that stock. Then you can leave the rest of the oem wiring in place and have the parallel wired in oil pressure switch. That will power the FP. If you want to keep the FP relay active during running you cna simply use a rpm trigger (or the unused idiot light terminal on your alternator, it provides 12V to switch off the idiot light - both sides 12V, effectively 0 - when the alt is charging)

Here's my procedure, I rewire the harness with all factory fuse holders, relays etc and simplify some of it (less splices, etc) and clean it up a little so it makes for a clean factory looking install. Not having FI and emissions junk sure helps eliminate clutter


this we do not want anymore


this has since gotten a lot cleaner. I had to repair all the wiring harneses and some other areas because some tool here in the Netherlands who thinks highly of himself (idiot who worked on this car in the past) thinks that proper wiring does not require a soldering iron and shrink sleeve but twisting wires, painters tape or duct tape and luster terminals