Putting a carburetor in a TBI based truck.

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Flextx500

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My kid has a TBI to 4bbl adapter plate. New, never used. He swapped the whole engine in his 94 to a ZZ4 350 crate motor and used a Fi-tech throttle body system. Still using the 4L60E with the factory computer for shifting. All we had to do was tie in the Fi-tech TPS to the factory wiring and he's been running it that way for 3 years now with no issues.
 

Jobey

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I swapped my 89 gmc to carb. I kept the factory in tank pump and put in a regular pressure regulator and it worked great. The only problem was if held at wide open for too long it would start to die out cause it was sucking the fuel out faster than the pump could provide. Mine was a pretty healthy build though. The nice part about the factory fuel injection system is that it has a return line so if you put a bypass style regulator it keeps your pump a lot cooler and should give it longer life I also accidentally clipped one of the heat sensor wires when I was cleaning it all up and it cut the power to the heater controls. If you wanted to eliminate the computer all together you’d have to get a w/t style heater controls and everything you’d need to swap it out. They are all mechanical. At least they are for the 89. Not sure about your year. Actually come to think of it I’m pretty sure they are all mechanical because I have a 96 w/t that’s all mechanical. Obviously the trans as well. The autos need the computer. That’s about it as far as I can remember. And to the guy talking about needing efi up north, I live in Minnesota. It could be 20 below and I could pump it twice and she’d fire up every single time without fail. It all depends on the motor. If yours is a little more particular about it in the cold you can always either get an electric choke or get a manual choke carb and your problem is solved.
 

Aem72717

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My 93 came half way converted over to a carburetor with the wires all cut half the gauges did not work no speedometer it was a mess I should of took it back to TBI it would of been easier but I liked the way the truck ran and sounded with the bigger cam and headers so I endeavored to get it lined out and you can make every bit of the factory options work I have the electronic A/C controller, cruise control factory gauge package all works it took a lot of time in the schematics to figure out all of it. The biggest pain was getting a solid and reliable fuel system as my block had no provision for a mechanical pump and previous owner had removed the return fuel line and believe me even if holley or whoever it is tells you that the pump will be good deadheading into a regulator don't listen to them they get hot and noisy as a lawnmower with no muffler and they will burn up at the most inconvenient time. I ended up welding a sump in my factory tank with a frame mounted pump and a bypass regulator on the firewall with a new return line. If you decide to go with the conversion I will dig out all of my wiring diagrams that I drew up so I would not forget the way I had to wire mine up and send them to you I would work with the TBI if at all possible though it's a dependable and easy system to work on
 
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kensa46

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I did my 96...it runs a lot better than it did with the old fuel injection..The hardest part of the swap was getting the fuel tank clean because it sat for a year with old gas from the previous owner...
 

thinger2

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If it is a 700r4 or a 4l60. Not a 4l60E
Pay really close attention to the TV cable.
It has to have the proper orientation between throttle opening and length of travel of the TV cable.
Because that cable controls line pressure and shift points.
You need to look at the diagrams for TV cable to throttle geometry.
Even if you change carbs you need to take that into account.
The geometry and orientation changes just by taking the quadrajet off and putting on a holley.
It changes again if you take the holley off and use an edelbrock.
And that can smoke the transmission
They used to sell corrective brackets for the carbed trucks way back in the day.
Ive never seen one for a tbi to carb swap but ive never looked for one either so who knows
 

Erik the Awful

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Schurkey

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Yeah, but you still need the correct geometry on the throttle lever, to hook the cable to.

AND--this is really hateful--the geometry for the 700/4L60 TV cable is not the same as the similar-looking stud for a TH350 kickdown cable.
 

thinger2

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Yep, here's the geometry as well as how to adjust the TV cable
Yessir
Back in the early 700r4 days transmission shops didnt know that.
It might have been an a TSB.
What made it especially frustrating and much more likely was offroading in Arizona and beating the snot out of it in Rocky Point.
And I really screwed myself because of Arizona emissions.
An 83 is all quadrajet and about 30 vacuum lines.
Arizona cooked my vacuum sphagetti.
So I would put the Q-jet back on, give a tune and pass.
And went home and yanked all that and put a Carter AFB or a Edelbrock or a Holley and drove it.
Not understanding that I was cooking my transmission.
All from the damn TV cable and its relationship between throttle position and the throw of the cable at the transmission.
I didnt know, the trans shops didnt know.
I drove this thing way deep into Mexico.
And came back with a case that looked like somebody was cooking inside it.
And that entire 4 year multi state multi country 5 thousand dollar ****** was because the trans people didnt know about it and I was screwing up their thought process by swapping carbs left and right.
I knew better, at least I thought did.
Back in high school everybody bought some ragged out 60s car and step number one was to put a barrel intake on it and some crappy headers
They come with stickers.
Cars are faster with stickers.
Slap a 4 barrel on.
Turn every screw in random ways on the hope it will make it run better.
Show up at the party with it stumbling pooping and farting.
Tell everbody you just put a cam in it.
You aint readdy to race anyone who calls ******** on you because you are still breaking in the cam.
Some knuclehead will call you out.
The trick is to get them so confident that are willing to rat race you through the narrow streets of Seattle for 500 dollars between point A to point B.
And bet your bone stock 1978 VW Rabbit against that big block heavy ass car.
I did pretty good back when we dragged down on Marginal way.
But I beat my cars down to diirt.
Rat Racing these days is an entirely different thing.
Everything they have is available dirt cheap and unstable and the auto industry has provided them with insane crazy **** built cars.
Back in the day we used to have a bunch of cash to build a death car.
Now you can just buy one cheap.
Back in the esrly 60s. They recognized that street racing was a problem..
So they opened the tracks and dragstrips to everbody. That is part of the origen story of racing in America.
And this is a big part of that assumtion and elitest notion from politicians.
They acually believe that we race because we dont understand how public transportation will make our lives better.
And you are a ******* criminal if you oppose it.
Nope. We are self satisfying
We fix our own **** by figuring it out.
I Look at it this way.
******* douchbag Putin can nuke me tomorrow.
Nothing I can do about that..
But my truck works becaause I fixed it and my dishwasher works because I fixed it and my water heater and every other damn thing.
Except the ******* pavement ants.
Those little ******** are on the verge of all out war.
I have yelled at them many times and they dont give a ****.
Ive poisned them many times and they dont give a ****
salad cuttings. The tops of carrots and the ends of oinions and just a little ground beef thrown across the alley into your neighbors back yard in the middle of the night will help.
If they catch you on camera throwing food into their backyard claim a religeous exemption that has a basis in Garlic and alien sasquatch bases on the far side of the moon.
Which is true.
Excect maybe the garlic part.
I know this is a bunch of nonsence.
I am waiting to find out what is going on with me.
But you people are awesome and amazing and kind.
 
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