i have a 81 k20 burb that i pulled a carbed 350sb and i am wanting to go back with a 84 tbi 350. i have the complete truck for the harness and anything else i will need. what are some of the hurdles that i will be up against as we do this? any advice will be greatly appreciated. thanks
CK5
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carb to tbi
- Thread starter leftyokie
- Start date
badmix
1/2 ton status
Gotta upgrade fuel system, Carb is low pressure, need a high pressure pump and regulator. Also will need O2 and Cats unless you get a "black box" that the ricers use to fool the computer and eliminate the cats.
ok, i knew about the fuel system but i wasnt thinking about the cats or O2 sensors so sounds like i need a black box? It is possible the donor truck has them, i will look tonight. now, where does one go about finding such a contraption? i will start looking online.
badmix
1/2 ton status
Just have to check on line for Cat eliminator electronics. Getting OEM stuff is always the best approach, if you can get the cats and O2 from the same truck you got TBI and harness, your better off.
Wait, what? An '84 was not TBI. '87 was first year in the trucks...
You don't need to worry about catalytic converter for OBD1, there is no monitoring of catalytic efficiency. It has no way of knowing whether the converter there is not. You will want/have to have an O2 sensor.
You don't need to worry about catalytic converter for OBD1, there is no monitoring of catalytic efficiency. It has no way of knowing whether the converter there is not. You will want/have to have an O2 sensor.
Yeah, not sure about TBI on an 84. But if it's a TBI and you have all the engine side stuff, I think it's just getting an O2 sensor and dealing with the fuel system. IMO there will be less long-run headaches if you mimic the TBI fuel system with an in tank pump and TBI style filter, etc. That way when stuff goes wrong in 3 years you know to just ask for parts from a 1990 K5 or whatever.
Going to be a bit more complex being a 1994, I assume the fuse panel isn't a "bolt in" for the older body style, but I really don't know. Component-wise should be pretty much the same setup though. Better ECM too if I'm not mistaken.
badmix
1/2 ton status
1) That is what I was thinking as well. be different if it was an 89 TBI but '94 may change things
2) I have a 84 K5, its Quadrajet Carb, not TBI.
EVERYTHING is removable, how hard that will be is the variable. 
A donor the same body style is always easier...fuel lines off the '94 won't work, tank/sending unit won't work, wiring lengths are going to be wrong, etc.
It's all stuff that can be worked around, but swaps always nickle and dime you to death. A 1987 donor K-truck (not suburban, crew cab, or blazer) would allow you to essentially unbolt everything from it, and all bolt on yours, which means there will be little to no surprises.
Don't get me wrong, it's doable, its just going to take more time and cost more.
A donor the same body style is always easier...fuel lines off the '94 won't work, tank/sending unit won't work, wiring lengths are going to be wrong, etc.
It's all stuff that can be worked around, but swaps always nickle and dime you to death. A 1987 donor K-truck (not suburban, crew cab, or blazer) would allow you to essentially unbolt everything from it, and all bolt on yours, which means there will be little to no surprises.
Don't get me wrong, it's doable, its just going to take more time and cost more.
Jessie James
1/2 ton status
As far as catalytic converters, they are cheap and easy to install and reduce tailpipe emissions a lot. I say this in terms of "you will choke to death without them" in some trucks. My 91 has a cat that was dead and it was unbearable to drive with the windows down until it was replaced.
Also, some states say if you now have 87 engine & emissions equipment on your truck, it ALL must be there, and therefore it's a felony to run without one. Big fines if you get caught.
Also, some states say if you now have 87 engine & emissions equipment on your truck, it ALL must be there, and therefore it's a felony to run without one. Big fines if you get caught.
You make a good point, I wasn't clear. I don't advocate running without a converter, anymore it's essentially pointless to remove one, or not run one if you have the ability, but as an expense they aren't necessary to the vehicle running properly.
They can indeed help immensely with how obnoxious the emissions from the tailpipe are.
They can indeed help immensely with how obnoxious the emissions from the tailpipe are.
Burbdood 74
Giver of not a single damn...
x 500%
The previous owner cut the cat out of my Suburban and it was f&%$king horrible! If you went anywhere near the tailpipe when it was running your eyes would just burn and choke you out. Put a new cat on a few months ago and it's a HUGE improvement. I'm not afraid of suffocating my family anymore while we drive with the windows down.
Jessie James
1/2 ton status
Yeah, my wife refused to ride with me until I fixed it. Can't have that!x 500%
The previous owner cut the cat out of my Suburban and it was f&%$king horrible! If you went anywhere near the tailpipe when it was running your eyes would just burn and choke you out. Put a new cat on a few months ago and it's a HUGE improvement. I'm not afraid of suffocating my family anymore while we drive with the windows down.
Burbdood 74
Giver of not a single damn...
Yeah, my wife refused to ride with me until I fixed it. Can't have that!
Sometimes wives that refuse to ride in your rig can be a good thing though, call it a sanctuary if you will....
Step 1: Sell the engine and stuff you have.
Step 2: Call up the guys at affordable fuel injection and order up a kit. Install and be happy.
I'm running one of their kits and couldn't be happier. Oh and I don't know what's up with you guys choking out with no cats. I dont run them and my truck burns ultra clean.
Step 2: Call up the guys at affordable fuel injection and order up a kit. Install and be happy.
I'm running one of their kits and couldn't be happier. Oh and I don't know what's up with you guys choking out with no cats. I dont run them and my truck burns ultra clean.
I don't run cats either on my 87 and its fine. No choking fumes or strange smell.
As far as fuel lines go the tbi doesn't really run a high pressure, under 20 psi at the high end. I think 17 psi is the high end. So its not like you are needing to change all your lines. I used normal everyday fuel line on my TBI and have had no problems in 4 years ( thats 4 years of wheeling not really daily driving). So fuel lines are not a big deal.
As far as computer and the rest I am not sure never swapped a newer TBI into anything just parts that were off random trucks
As far as fuel lines go the tbi doesn't really run a high pressure, under 20 psi at the high end. I think 17 psi is the high end. So its not like you are needing to change all your lines. I used normal everyday fuel line on my TBI and have had no problems in 4 years ( thats 4 years of wheeling not really daily driving). So fuel lines are not a big deal.
As far as computer and the rest I am not sure never swapped a newer TBI into anything just parts that were off random trucks
94 TBI system if coming from an Auto trans is for E trans and must have a VSS. Although I did tune one once without and it was fine, the complications of tuning were not worth the time involved.
Reason is the newer 16197427 PCM has 2 fuel and spark tables, one for idle and one for off idle, many other things also look to if vehicle is moving or not.
The entire wiring harness can be reworked for powers and grounds, not that hard you just do it like an aftermarket harness would. One wire at a time and it takes time.
Reason is the newer 16197427 PCM has 2 fuel and spark tables, one for idle and one for off idle, many other things also look to if vehicle is moving or not.
The entire wiring harness can be reworked for powers and grounds, not that hard you just do it like an aftermarket harness would. One wire at a time and it takes time.
