[ChevroletSS]

Can you all help me out with what I will need to do a TBI to Carb conversion. Its on my chevy truck. I know I need: Braided fuel line, Fuel pressure regulator, HEI distributor, and I cant think of anything else besides carb and intake. As far a a regulator I have seen alot of different ones but I dont know which one to get. Can anyone help me out with a link to one.

Thanks....SS

[64nailhead]

If you check out diyautotune.com site you'll find there is a section with directions on how this guy converted his carbed 350 to tbi. He is using a megasquirt ecm, which you do not have to use, but if you read and watch the 1st and 2nd parts of the conversion, then you'll find all of the parts needed.

In terms of parts, a short list is intake and coolant temp sensors (same sensor), IAC and TPS that is on the GM TBI, and MAP or MAF sensor depending on ecm being used. Fuel pump rated for the TBI you have. If you are using a stock GM TBI, then I believe the fuel pressure regulator is built into the throttle body. Also, if using the stock TBI, then you'll need both lines (steel braided) that attach to the rear, properly rated fuel pump, and a fuel filter rated for the TBI unit (micron size). Now that I've typed all of this, are you planning on using an aftermarket setup or stock setup?

What are you planning on using for an ecm?

And also, if you are running something like Megasquirt, you don't have to swap distributor's, but is highly recommended. Otherwise you have to know exactly what is going on with your distributor in terms of vacuum and centrifugal advance at varying MAP readings. Basically you have to have your old distributor tuned - MUCH easier to bolt on the HEI unit!

[ChevroletSS]

I think your explain going from carb to tbi. I want to eliminate my tbi and computer and bolt on a carb

[gearheadslife]

Originally Posted by ChevroletSS

Can you all help me out with what I will need to do a TBI to Carb conversion. Its on my chevy truck. I know I need: Braided fuel line, Fuel pressure regulator, HEI distributor, and I cant think of anything else besides carb and intake. As far a a regulator I have seen alot of different ones but I dont know which one to get. Can anyone help me out with a link to one.

Thanks....SS

you didn't say what year truck... but I'll guess some

you'll need what you listed..
the fuel reg. can't be what they call a deadhead. you have to use one that uses a return line.
if your trans is computer controlled it will not like this at all and you'll be forced into a stand allone controller
if the tranks is a 7004r you'll need the correct t.v. cable and brackets . if factory intake you can use the factory brackets, if aftermarket you'll need to get the brackets that work with that intake.. edel/etc makes/sells them..
you'll need a hei thats not computer controlled..

your check engine light will be on. if they plug into the service port for state inspection. you'll fail..
your cruise will not work..
and your speedo might not also (not knowing the year/model)
good luck

[ap72]

Originally Posted by ChevroletSS

I think your explain going from carb to tbi. I want to eliminate my tbi and computer and bolt on a carb

Why?

[malc]

This might help TPI -> Carburation!!!

[oldbogie]

Originally Posted by ChevroletSS

Can you all help me out with what I will need to do a TBI to Carb conversion. Its on my chevy truck. I know I need: Braided fuel line, Fuel pressure regulator, HEI distributor, and I cant think of anything else besides carb and intake. As far a a regulator I have seen alot of different ones but I dont know which one to get. Can anyone help me out with a link to one.

Thanks....SS

Depends on year and transmission. For a stick no problem, for a 700R4/4L60 analog 4 speed automatic no problem, for the 4L60E (E for electronic) digital 4 speed automatic, 1993 in some cases and 1994 up in all cases it's a PIA to keep needed sensor data flowing to the tranny.

For the manual gear box or 700R4/4L60 automatic you will need an adjustable bypassing regulator to drop the fuel pressure to 4-6 psi. I know these regulators are expensive but by the time you fiddle the existing fuel system to accept a low pressure pump you'll spend this much or more and have to do a lot of plumbing and wiring work to boot, so the expensive regulator is the easy way through the problem of fuel pressure. by p****ing regulators prevent the pump from dead heading when the enigne is idleing preventing the electric pump from overheating Other than that you'll need a 4 barrel intake that bolts to the Swirl Port heads, the difference between these and older heads is just the angle the bolts make to the head's intake mounting surface pre 1987 use a 90 degree angle 1987 up use a 72 degree angle. Open the instrument cluster and remove the bulb from the check engine light. Hardwire the fuel pump relay to the ignition switch as the computer is looking for a tach signal to keep the fuel pump running, if you change the distributor to an older HEI (and who wouldn't in this case) there is no point to keeping the computer in the distributor loop so there will be no tach signal to the computer, so the hard wire gets around all that.

Note, this is NOT LEGAL to do anywhere in the U.S. while your state may not enforce Federal Law on emissions nor have emissions laws itself; it still is a Federal Law; so be aware of that.

Bogie

[ChevroletSS]

Well I am not 100% sure of what my transmission is. I thought it is the 4L60E but How do I tell. Looks like that is my only issue Im going to have to deal with. If it is a 4L60E could I Use a computer out of a truck with a manual trans and take care of it. First tho how do I tell what trans it is? It is a 94 so Im guessing it is computer controlled. If it is what year trucks had the 4L60 in them so I can get on or is the 700r4 the same length.

[gearheadslife]

FYI... the ecu (computer) controls all the dash gauges

[malc]

Originally Posted by gearheadslife

FYI... the ecu (computer) controls all the dash gauges

I took the ECU out of my Camaro and the gauges were not affected.
Is it different for TBI motors ?

[ChevroletSS]

I know my oil pressure, coolant temp, volts, fuel has nothing to do with my computer. speedo is hooked up to my trans and my tach is hooked into my distributor.

[malc]

Originally Posted by ChevroletSS

I know my oil pressure, coolant temp, volts, fuel has nothing to do with my computer. speedo is hooked up to my trans and my tach is hooked into my distributor.

Same here.
ECU just ran the carb/trans.

[oldbogie]

Originally Posted by ChevroletSS

Well I am not 100% sure of what my transmission is. I thought it is the 4L60E but How do I tell. Looks like that is my only issue Im going to have to deal with. If it is a 4L60E could I Use a computer out of a truck with a manual trans and take care of it. First tho how do I tell what trans it is? It is a 94 so Im guessing it is computer controlled. If it is what year trucks had the 4L60 in them so I can get on or is the 700r4 the same length.

The 700R4/4L60 will have a mechanical cable link coming from the TBI throttle linkage which is the modulator control; the 4L60E will not have any mechanical linkage or cable connection with the throttle linkage. Underneath the 4L60E will have a big black box on the driver's side that the shift lever connects to and a very large wire bundle that enters the case on the passenger side.

If this has the 4L60E, my advice would be to fix the TBI. Not knowing why you want to replace the TBI if it's malfunctioning or you want more performance. Either-way it's probably less expensive to repair or hot rod the TBI. The 4L60E can be operated from a standalone controller but this isn't very cheap. The other way would be to put in a 700R4/4L60. There is no cheap solution to the fully electronic vehicles that start with the 93-95 late OBD I production and it only gets worse with 96 up OBD II production. The levels of Systems Integration just keep increasing making it ever-more expensive and difficult to simple these later model vehicles.

Bogie

[ChevroletSS]

So are you sayin the none computer trans 4L60 has two cables hooked to the throttle body. There def is not a black cox down there

[gearheadslife]

Originally Posted by ChevroletSS

I know my oil pressure, coolant temp, volts, fuel has nothing to do with my computer. speedo is hooked up to my trans and my tach is hooked into my distributor.

and you'd be incorrect..
the collant tepm. sender tells the ecu if it's cold out.. and richen it up..
fyi if sender is junk the ecu goes in to limp home mode (i.e. rich)
no oil psi.. no fuel pmp power.. yes it's not as involved as a 2012 truck.. but it all works together..

malc, your f body is from the 80's..
the trucks started with the ecu controlling more of the dash in the changeover in the late 80's