TBI TO CARB CONVERSION

[JACK34]

Please keep this info coming. Hopefully we can get this figured out. Thanks to all.

 

[PlayingWithTBI]

Doesn't this early of a truck have a 700r4 if it's an auto?

Yep, it still has a TCC but, you can run it without, you'd still have 4th gear.

OP - did anyone put a scanner, not a code reader, on it to data log and watch for what changes when it runs bad?

 

[JACK34]

The less power/drivability and gas mileage issues blah blah that everyone says is, as far as I've found, a myth. I have drove 2 carbureted trucks of these models, 94 and 96. I used to have an 82 C10 with a carbureted 350 (I know it's different technology and older but still same concept). I am even considering a carb swap on my 95 now but money is holding me back for now. First thing's first is to figure out if you have the 700r4 or the 4L60E, if you got a 700r4 then you will have to buy a "detent cable adapter kit for carbs" or "tv cable adapter kit for carbs" something along those lines, if you have the 4L60E then you will either have to buy a separate trans controller or do some wire splicing and modification to the trans harness to shift properly with a carb TPS kit you can buy online, but that's a whole 'nother story and thread to talk about... if you have a manual trans then you don't have to worry about the trans. Then you will have to have an inline fuel pressure regulator that has a return line system for the stock TBI fuel pump. Next is you will have to get a carb of your choice (I'd recommend 600cfm for stock motor), a carb intake (my recommendation is the edelbrock 2104 dual plane intake) this intake is made for the TBI heads and center bolt heads. Then you will have to get an HEI distributor to replace the old TBI one. You would then just put all the parts on the motor like you normally would if you were building one. Only thing to keep in mind is your fuel pressure and detent cable for auto trans. I believe carb fuel pressure if between 5-13 psi (you'd have to look up what is recommend for your motor and your carb). Also make sure the return fuel line is hooked up or you could burn up your TBI pump. The detent cable will have to be adjusted to shift properly with the carb and for your specific circumstance. I believe that's all is needed, if I forgot something and remember it I will edit and make sure it's known. Good luck!

But that isn't getting to the root cause of his problem.

 

[Aidan Kesler]

But that isn't getting to the root cause of his problem.

I was just explaining how to do a TBI to carb swap if he needed some information, not explaining his issue.

 

[JACK34]

I was just explaining how to do a TBI to carb swap if he needed some information, not explaining his issue.

Copy. I appreciate the info thank you.

 

[JACK34]

He did just tell me he has gas in his oil.

 

[Gramps]

Needs to go on a scAnner with live data feed.

oil smells gassy? I’d venture a guess with the lack of power and general poor driveability the coolant temp sensor (not the temp switch for the guage) is probably shot, they default to telling the ecm that it’s -40degrees so the ecm over fuels - like running with the choke on.

 

[JACK34]

I was just explaining how to do a TBI to carb swap if he needed some information, not explaining his issue.

Sorry I re read your post good info thank you.

 

[JACK34]

Needs to go on a scAnner with live data feed.

oil smells gassy? I’d venture a guess with the lack of power and general poor driveability the coolant temp sensor (not the temp switch for the guage) is probably shot, they default to telling the ecm that it’s -40degrees so the ecm over fuels - like running with the choke on.

Yeah that makes sense I will tell him. Like I said he's pretty set on changing to a carb out of frustration now but maybe something simple got overlooked. In regards to the carb swap Aidan described, does that take all of the electronic sensors computer etc out of the loop? In other words is that stuff just unplugged or removed and you are now just dealing with a carb and distributor to tune and the standard vacuum lines like a older truck would have had. Hope that makes some kind of sense. Thanks Gramps I hope what you said they haven't done and it works.

 

[Pinger]

Needs to go on a scAnner with live data feed.

oil smells gassy? I’d venture a guess with the lack of power and general poor driveability the coolant temp sensor (not the temp switch for the guage) is probably shot, they default to telling the ecm that it’s -40degrees so the ecm over fuels - like running with the choke on.

Injector stuck/sticking open?
Stuck fuel pressure regulator?