Tbi to carb swap - what wires are and aren't needed?

[NeatEvenin]

Hey guys, I'm new here. I've got a 1992 k1500 with the 5.7 and 700r4, I'm converting to carb. Got a whole new block and everything. Yes,I know it's been done a million times and I'm still confused, but the block is set up to be dropped in, and the task of dealing with the wiring harness and ecm is daunting and preventing me from moving on. Is there any way to get rid of the harness that controls the TBI and the EGR? I'm trying to keep my stock gauges and the electric fuel pump. Any answers?

 

[thatclappedsilverado]

use tbi sensors for: oil pressure and coolant temp purple and white wires from coil will be tied to tach on the hei dist. red will go to 12v for hei. you'll pretty much keep all of the wiring and i'd personally reccomend keeping it with the harness instead of cutting it out incase you go back to tbi like i did. that way you don't have to source a new harness. using the factory harness and sensors will allow everything to still work correctly without input from ecm. but why swap to a carb? tbi is super reliable with some basic maintenance done.

 

[NeatEvenin]

Unplugging things like the iac, tps, and EGR stuff won't throw any trouble codes, will they? I can just tuck those connectors away under the loom?

Edit: I'd also include the map sensor in this question, and unplugging these won't interfere with fuel delivery?

Edit #2: the reason I'm swapping to carb is because I wanted more power than the TBI could offer,also because doing an LS swap isn't in my budget and I had the block already, so I thought I'd drop it in, and it's all set up and ready to go,save for the wiring.

 

[Schurkey]

Perhaps a moderator will move this thread to the LSX + Carb Swaps sub-forum.

 

[RoyBob]

Just finished my 89 not real sure on the wires for your year, mine was not bad at all.. I can say My cruse still works and all my gauges and speedo. and what

thatclappedsilverad posted while the engine is out is the time to clean up the harness

You must be registered for see images attach

 

[NeatEvenin]

Just finished my 89 not real sure on the wires for your year, mine was not bad at all.. I can say My cruse still works and all my gauges and speedo. and what

thatclappedsilverad posted while the engine is out is the time to clean up the harness

You must be registered for see images attach

The wiring for our trucks is the same, did you tuck any wires away or do anything to hide the wires you didn't need?

 

[RoyBob]

Yes so all the wires that i didnot use I tucked them under the Blower box on the pass side fender well, I used one wire off the TBI wires(there are 4) i used it for the electric choke ,its hot with key on, are you going to use the in tank pump ? and a HEI distributor, i kept the oil pressure switch at he rear of the engine its a 2 wire plug , there are a ton of videos Bet i watched them all .. I removed the connectors from my harness on wires i didn't use and put but connectors on Just encase i ever wanted to change back ..

 

[Scooterwrench]

You will need the power feed wire off the starter,the large purple wire for the starter solenoid,the pink power wire to the coil,the white tach wire,the tan wire for the OP gauge,and the dark green wire for the temp. gauge. If you're carb has an electric choke you can use the pink/black wire off the EGR control valve to power it or T off from the pink wire feeding the dist. You will need a vacuum operated electric switch to run the TCC. Only other wire would be the green wire for the A/C clutch if you're gonna run it.
If you haven't done so yet download the FSM for your truck in the sticky and study the wiring schematic well.

 

[thatclappedsilverado]

Unplugging things like the iac, tps, and EGR stuff won't throw any trouble codes, will they? I can just tuck those connectors away under the loom?

Edit: I'd also include the map sensor in this question, and unplugging these won't interfere with fuel delivery?

Edit #2: the reason I'm swapping to carb is because I wanted more power than the TBI could offer,also because doing an LS swap isn't in my budget and I had the block already, so I thought I'd drop it in, and it's all set up and ready to go,save for the wiring.

theyre going to throw codes, you will have a check engine light on all the time with doing away with the tbi unit. As for making power with the tbi, in its factory form it should support around 250-280hp with a vortec pump in the tank and an aftermarket regulator. Carbs are great i had on on my truck for the last few years but the tbi is simple and reliable like i said. And like RoyBob said if your gonna hide the harness the time to do it is when the engine is out. Theyre simple to swap if you know what your doing. If you know nothing about carbed engines its not the best idea. Reguardless its your truck you do what makes you happy n well try to help you along the way. What are your power goals? What do you use the truck for? Is it your daily driver? Does the tbi work as of right now?
Not trying to deter you just trying to give my 2c on the matter.

Just finished my 89 not real sure on the wires for your year, mine was not bad at all.. I can say My cruse still works and all my gauges and speedo. and what

thatclappedsilverad posted while the engine is out is the time to clean up the harness

You must be registered for see images attach

 

[thatclappedsilverado]

Also food for thought what trans? Auto/Manual? manual is simple auto gets a bit more complicated depending on the tv cable or electronics depending on year and trans.