Slant Six Forum :: Early 90's chevy 4.3 TBI Conversion?

Quote:

Good thing about TBI is it uses a wet manifold delivery like your carb does, it uses a MAP sensor to determine load, and you can wire your trigger system off of the magnetic pick-up in your dizzy

Hmm... generally speaking a dry manifold is preferred to wet one. You won't have fuel distribution issues or fuel condensation or puddling. Also, if you think you can hook a mopar EI distributor directly to a GM TBI computer, well, your going to be in for a rude awakening. Been there, done that, got the t-shirt. Won't work. You need a special filter inline and even then its a crapshoot. You have to use a HEI or MSD type module in the middle between the computer and distributor. You can do fuel only too on them.

$200 new or used is not going to happen. You'd trust a used junkyard electric fuel pump? A used sensor? Really? Good luck. I mean you no offense, but the folks that think it's doable for that have only done it on paper not in real life. Don't forget throttle/kickdown linkage. EFI rubber fuel hose alone is in the $5/ft range. My goal here isn't to berate you but to avoid giving people false hope.

Author:	moparlewellen [ Tue Apr 08, 2014 7:23 pm ]
Post subject:	Early 90's chevy 4.3 TBI Conversion?
I was thinking, would a early 90's 4.3 TBI work with a slant? Ive got a 4bbl currently. I figure i would need an adapter plate, o2 sensor, chevy wiring harness and computer. Would this work and could it be done for under $200?

Author:	Pierre [ Tue Apr 08, 2014 9:37 pm ]
Post subject:
Work? Yes. $200? Heck no. Pump and plumbing alone will cost you that much if your thrifty. TBI is low pressure but its not as low as a carb. The regulator built into the tbi is 13psi. The associated pump puts out 18psi dead head iirc. The associated chevy 1227747 computer has been hacked thoroughly. There are businesses out there making a living at this sort of thing.

Author:	kesteb [ Tue Apr 08, 2014 10:11 pm ]
Post subject:
And by the time you get through hacking the GM computer you could have boughten a Mega-squirt.

Author:	Pierre [ Tue Apr 08, 2014 11:13 pm ]
Post subject:
There really isn't much hacking to do yourself. It's all been done. Just a matter of programming a chip. Even if you didn't want to buy a programer and do it yourself the places mentioned (such as howellefi.com) will make you a custom chip for a moderate fee if you give them basic parameters like engine and injector size. As far as versatility and features, yes the MS is a no brainer. Unless you get an old/used version though MS will cost more then a ebay 1227747 + chip. Either way, total systems gonna be way more then $200.

Author:	Doctor Injector [ Sat Apr 12, 2014 10:37 pm ]
Post subject:	Gm Tbi
We are installing this same system on a a 302 in a 67 Mustang with injectors from a 305.The throttle body's from 350, 305, and 4.3 are all the same size, just the injectors are different. Its also not that hard to make a adjustable fuel regulator out of a stock regulator housing to try and pump it up jus a little. Other then thinning out the wiring harness, not much else is being modified as of right now. We are going to put it together and see how it runs. I rebuild alot of these throttle body's and flow test and clean the injectors. On this on it is actually for my friends nephew. He got a throttle body adapter from ebay. http://www.ebay.com/itm/CHEVY-TBI-Fuel- ... 21&vxp=mtr[/img]

Slant Six Forum https://www.slantsix.org/forum/

Early 90's chevy 4.3 TBI Conversion? https://www.slantsix.org/forum/viewtopic.php?t=55067	Page 1 of 2

Author:	oldskoolracer [ Mon Apr 14, 2014 1:08 pm ]
Post subject:
If your buying anything new, $200 isnt even close... If your thrifty, shop around, hit some junk yards, then I dont see why you cant pick up all the sensors, solenoids and wiring for dirt cheap... The rest is a matter of making it fit your application. Good thing about TBI is it uses a wet manifold delivery like your carb does, it uses a MAP sensor to determine load, and you can wire your trigger system off of the magnetic pick-up in your dizzy... I really wouldnt be surprised if you slapped a 6cyl system on there and it run pretty good. Obviously nothing is gonna be "plug-n-play", but if your good with electrical, and can handle some wiring and minor fab work you'll be golden. I say go for it, and let us know. This swap is on my very near future "to-do" list on mine. I have reached the end of my patience with the Carter 2bbl set-up... Just sick of dealing with carbs in general, fuel injection is so much easier on a daily basis!

Author:	dartsport76 [ Mon Apr 14, 2014 3:15 pm ]
Post subject:
Extremely interested. I have pondered this same subject for a while, but have put it on the back burner for now

Author:	Pierre [ Mon Apr 14, 2014 8:28 pm ]
Post subject:
Quote: Good thing about TBI is it uses a wet manifold delivery like your carb does, it uses a MAP sensor to determine load, and you can wire your trigger system off of the magnetic pick-up in your dizzy Hmm... generally speaking a dry manifold is preferred to wet one. You won't have fuel distribution issues or fuel condensation or puddling. Also, if you think you can hook a mopar EI distributor directly to a GM TBI computer, well, your going to be in for a rude awakening. Been there, done that, got the t-shirt. Won't work. You need a special filter inline and even then its a crapshoot. You have to use a HEI or MSD type module in the middle between the computer and distributor. You can do fuel only too on them. $200 new or used is not going to happen. You'd trust a used junkyard electric fuel pump? A used sensor? Really? Good luck. I mean you no offense, but the folks that think it's doable for that have only done it on paper not in real life. Don't forget throttle/kickdown linkage. EFI rubber fuel hose alone is in the $5/ft range. My goal here isn't to berate you but to avoid giving people false hope.

Author:	moparlewellen [ Mon Apr 14, 2014 9:44 pm ]
Post subject:
My thought was if I were to get throttle body and wiring for free, would it be "plug n' play" but you guys answered that. I kinda figured it wouldn't be because any kind of non universal part requires some kind of mod. It would be pretty cool though. Maybe in the future when I can spend $1000 on it.

Author:	oldskoolracer [ Wed Apr 16, 2014 5:34 pm ]
Post subject:
Quote: Quote: Good thing about TBI is it uses a wet manifold delivery like your carb does, it uses a MAP sensor to determine load, and you can wire your trigger system off of the magnetic pick-up in your dizzy Hmm... generally speaking a dry manifold is preferred to wet one. You won't have fuel distribution issues or fuel condensation or puddling. Also, if you think you can hook a mopar EI distributor directly to a GM TBI computer, well, your going to be in for a rude awakening. Been there, done that, got the t-shirt. Won't work. You need a special filter inline and even then its a crapshoot. You have to use a HEI or MSD type module in the middle between the computer and distributor. You can do fuel only too on them. $200 new or used is not going to happen. You'd trust a used junkyard electric fuel pump? A used sensor? Really? Good luck. I mean you no offense, but the folks that think it's doable for that have only done it on paper not in real life. Don't forget throttle/kickdown linkage. EFI rubber fuel hose alone is in the $5/ft range. My goal here isn't to berate you but to avoid giving people false hope. Why yes you are very right, a dry manifold and multi-point injection is the best of all worlds. HOWEVER, it also requires the most extensive modifications, tuning, and programming. Wich gets very far away form "budget". What I was referring to is th simplicity of the system because it acts much like a carburetor with the benifits of better fuel control thanks to computers and electronic timing. Again your right, you would need the GM 7-pin module between the dizzy and ECU (just as GM did) in order to run the injection, as well as ignition. The point is that the magnetic pick-up gives the same signal as the one in the GM dizzy. Plug-n-play?...No. Doable?... Sure with the right amount of time, research and electrical know-how... And to get it totally right requires the removal of the mechanical and vacuum advance from the dizzy and fixing it at 0* to take advantage of the electronic timing (of course that requires the proper module, timing control module, knock sensor, and hoping the GM timing curve will work out well for a slant, on top of various other factors) As far as trusting junk yard parts? Sure I do, have in the past, have recently and will continue to in the future. You cant use the GM fuel pump anyway being that it is in the tank, but as for sensors and solenoids modules etc, sure Ill pull em and give them a try. You may even get lucky and find someone parting out a running vehicle... Is all this doable at $200? I agree with absolutely not! Is it doable under $1000? Quite possibly! Just keep in mind that when looking for "cheap", your going to do ALOT of work and fab on your own. If you want "easy" or "plug-n-play" you better dig very deep into your pockets because your paying for all new parts as well as paying for someone elses time, knowledge, and over-head... There is alot to consider, and nothing is going to be direct and easy to work with, but nothing is impossible if you put your mind heart and soul into it.

Author:	ntsqd [ Tue May 06, 2014 7:55 pm ]
Post subject:
I'm headed down this road using a 2.8L TBI from an S-10 on my 170. The TBI, wire loom, all sensors, and 2.8L computer were free. Bought the pump new. Currently running on the return system using a Holley by-passing FPR down to carb pressure. New 3/8" supply with the OE 5/15" tube used for the return. Adapter I'll make since it's a Clifford intake & uses a non-std adapter to any carb. GM dizzy conversion is already done. Started on the wiring loom. Have the temp sensor in place. Probably have $200-$250 in it so far.

Author:	Doctor Injector [ Wed May 07, 2014 11:15 pm ]
Post subject:	Gm Tbi
ntsqd Please keep us posted on your progress. That is very cool.

Author:	ntsqd [ Thu May 08, 2014 6:07 am ]
Post subject:
The hope is that the 2.8's (173ci) fuel, and eventually IGN, curves are close enough that I can just drive it. The car is supposed to be mostly a DD. I also have a 7477 ECU if I have to go down the burning chips road, but I'd rather not. Updates as they happen will be in my build thread.

Author:	Tim Keith [ Wed May 14, 2014 6:10 pm ]
Post subject:
I want to use two TBI units on the offenhauser 2 x 1 manifold

Page 1 of 2	All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited https://www.phpbb.com/

Author:	Pierre [ Wed May 14, 2014 9:23 pm ]
Post subject:
Quote: I want to use two TBI units on the offenhauser 2 x 1 manifold That's going to be a tight fit. I put one (2bbl tbi off a 4.3L, think the smaller ones are the same flange but different bore/injector sizes?) on a clifford 4bbl and remember having 1-2mm overlap for the gasket to seal. I think the offy 2x1 manifold flange is going to be too small, even if you open up the hole. Flange aside, these use the common aftermarket 4bbl air cleaner. That flange is rather big, unsure two will fit side by side and still be centered on the manifold. Do some mockups before making any permanent plans.