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Old 12-17-2018, 01:48 PM   #1
tlindsey
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TBI vs Carb

I'm in the process of having my engine redone(its pulled and waiting to go).....I'm really wanting to mod it a little, get more horsepower, something other than a stock 350 TBI! Now, some others have said why not just go with a carb and forget about TBI...I kind of like that BUT what does a person do with all the sensors and the computer? That is the part that freaks me out about changing anything. I have even considered going with Vortec heads/intake and a nice cam....but what about PCM and the mounting location for the MAF (which is on the current intake)?? Any input or guidance is greatly appreciated. I'm kind of new to the Fuel injection scene, lol.
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Old 12-18-2018, 02:12 PM   #2
i_live_in_canada
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Re: TBI vs Carb

i would swap tbi to carb anyday. the tbi system isnt very great if you want to make power. i will be ls swapping my 1990 chevy soon but i am going carb. im not sure about all the sensors and the ecm. guess ill find out when i do it.
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Old 12-19-2018, 09:03 AM   #3
Stormin08
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Re: TBI vs Carb

my build thread is just that...i yanked all the factory sensors and wiring...installed a stand alone efi unit.

it runs and functions fine now, just waiting to finish some detailing items and post new pics.


all in all, a carb WILL make more power if playing field i leveled. a carb's intake air temps are far lower than any efi system i have seen. most see right at 34*F under the carb base...

the efi is an easier starting and driving system, so it is a personal preference. the efi is far less touchy to atmospheric conditions.
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Old 12-19-2018, 09:19 AM   #4
rpmerf
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Re: TBI vs Carb

What year is your truck?

If you wanted to go Vortec heads, intake, and fuel injection, you might be better off grabbing a whole wiring harness and ECU.

Going to carb, you can eliminate most of the wires, or just leave them in place. Most important things are power to the coil, starter, alternator connected and working, and your gauges work.
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Old 12-19-2018, 09:50 AM   #5
tlindsey
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Re: TBI vs Carb

Sounds like my truck would never run again! Just learned yesterday that the oil pressure sensor next to the distributor (mine has two, one near oil filter as well) will not allow the fuel pump to operate if it senses no oil pressure....those are the things that freak me out, by not knowing what wire or sensor controls what. The ol days were so much simpler with no sensors and minimal wires. So if that one sensor goes bad and it talks to fuel pump, how in the world would nyone even start to think to look there??!!
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Old 12-19-2018, 12:06 PM   #6
rpmerf
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Re: TBI vs Carb

A fuel injection fuel pump wouldn't be what you want for a carb. They run like 40-60 PSI. You want one made for a carb, like 5-7 PSI. Might be able to leave the old fuel pump in place and install an inline pump for the carb.

If you have a fuel pump hole on your block, you could install a mechanical fuel pump. forget what year they stopped drilling that hole.

I would look at it more like what do you need. For the engine to run, you need power to the coil, power to the starter, fuel, cooling system, and an exhaust system. The start circuit will be the same, but you might need to modify the run circuit. Now sure how it is laid out currently. You will want gauges. You will need to look at schematics to see if the gauges work directly off the sensors, or if they go through the ECU.

Not sure about the tuneability of the TBI ECU. Might be worth looking into.
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Old 12-19-2018, 12:25 PM   #7
tlindsey
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Re: TBI vs Carb

Thanks, thats great info.
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Old 12-20-2018, 10:22 AM   #8
Stormin08
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Re: TBI vs Carb

under the brake booster if the fuel pump harness connector ( 2 wires)....power and ground.

i just went through this. all factory ECU & WIRING is gone.

the wiring looks intimidating as it routes in and out of the ecu, to the engine and back into cab for some gauge interface.

most is redundant, if chase a schematic, the gauges have their own sensors, the ecu has its own, but talks through the check engine light.

not much to these trucks pre 95.
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