Throttle Body Injection change over,,,,?

Joe, don't go backwards, you will spend as much for a carb and intake, gaskets, antifreeze and the list goes on as you would to get the truck running top notch with injection. Did this just start or been happening for a while. Check the timing, while doing that look for a vacuum leak like a hose pulled off or weathered away, spray carb cleaner around injector body to see if there is a leak there, notorious for the base gasket to start leaking. If that fails go to parts store and have them put a scanner on it and see if there are any codes. Probably gonna be a simple fix. Worst case bad ecm and they can be had online for a couple hundred bucks. Don't give up, if selling, the next person isn't gonna want a carburator. Just my thoughts. Is that a square body truck, that is about the time they were changing over, if so they are in demand and 4x4 would be a plus. Good luck and keep us posted

Usually a pretty easy system and the first step above a carburetor. Biggest trouble with them was vacuum leakage, and low fuel supply pressure. Reman units were the way to go back in the 90's, but the technology was current and parts were readily available.

I've not worked on one in years but cannot see why they would not still be available.

That's All Folks!

this....

https://www.carburetion.com/CarbNumber.asp?Number=17087021

what you got ???

3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Better response and fuel economy of a TBI, Quadrajunks are history as unable to find midbodies in decent enough shape to rebuild. Biggest problem gas leakage past the Swedged in Plugs from Corrosion under the metering rod wells. Are a few late model Aftermarket Four Barrels but as I stated, will NOT EVER match the available flows from a functional TBI. Late model blocks have NO provisions for Mechanical pumps even as casting still had the plated holes.

DrAllis wrote:

Start with an honest compression test of the engine before doing ANYTHING ELSE. Know that you have a healthy engine to work with !!!

Hey Dr. Allis,,that right there was first thing I done when I bought the trk was to run a compression test.,,, Wink

The readings were very even across from 150 to 155. I always check the exhaust pipe for further proof of engine passing any oil and exhaust was nice and dry with a slight gray powder feel.. The trk was bought new and the guy added a welding bed and was used all it's life in oil fields of Oklahoma and I bought it with only 68,000 miles on the clock .

Thanks for the interest. Clap

Thad, seen actual Dyno tests TBI can deliver well atomized higher pressure gas near to 1100 cfm and Two barrel, QJ worked up to 850/900 depending on metering system. Crate engines will come bored for but lack Mechanical pump push rod. Engines newer than 04 have no bore for the pushrod and no cam lobe. Engine electronics can vary timing out to 65 degrees, cannot get close to that all
Mechanical.

Fixing to FAFO if go there so do not be angry.

Edited by DMiller - 07 Jul 2024 at 5:31pm

Well,,,I finally got the cobwebs outa my brain and remembered I DID have a spare manifold with a perfectly good TBI that was operating good when manifold was removed from it's 454. I had "saved" it for no reason, just did not want to throw it away,,,

This intake with TBI came off a 454 I had bought to put

in the the Black Square Body after the camshaft went flat right after I bought the truck,,anyone remember that story about 2 years ago,,,? I installed an aluminum intake on that 454 with a 750 Holly, then sold the trk at a very good profit,,,,,!!! Clap

Anyway, I dug thru my stash in boat shed and LO,,,there it still was and just waiting on ole Joe,,,, LOL

TBI unit did not need any cleaning but during removal of the old TBI, I find 3 vacuum hoses that were most likely leaking,,PLUS, a weird happening,,,the btm gasket between a "Cooling water adapter" and BTM of TBI unit appeared to be leaking fuel while engine was shut down,,,,?? WTH,,,?? I HAD sprayed this area liberally with carb cleaner with engine running and did not notice any change in rpms,,,??? HMMMmm

Decided to remove that adapter to also replace the gasket UNDER this "adapter" and find yet another Oh-Oh. There is a 5/8" metal pipe at back of TBI that takes cooling water from under TBI to the truck heater,,it had also been leaking but leak was not visible until TBI is removed,,it has a really weird connecting fitting at the manifold,,,SHEEEESH,,,!! It has 1" NPT with a kind of slip fit of pipe into the NPT fitting,,,???

Can't wait to see how the engine will run with all these Oh, Oh's are fixed,,,, Clap

Hey Dakota,,,I don't have an idee when the vortec engines came into existence,, altho,, I think Thad and I were discussing early 7.4 engines,,, I don't remember which BBC 454 I used on the Black Beauty Square Body,,,just remember the cylinder heads were of the large round port design and the aluminum intake I used bolted right up on them heads.

DMiller wrote:

Thad, seen actual Dyno tests TBI can deliver well atomized higher pressure gas near to 1100 cfm and Two barrel, QJ worked up to 850/900 depending on metering system. Crate engines will come bored for but lack Mechanical pump push rod. Engines newer than 04 have no bore for the pushrod and no cam lobe. Engine electronics can vary timing out to 65 degrees, cannot get close to that all
Mechanical.

Fixing to FAFO if go there so do not be angry.

I been following this thread cause,,,well,,,just cause,,,,Still trying to decipher what FAFO means,,,? Wink

Thank you for the clarification,, DiyDave. That is bothersome,,,,

Codger wrote:

The TBI systems in common use those days were a very reliable system but barely one step above a carburetor in most circumstances.

I'm not certain where you get this, but anyone who looks at the performance figures of a vehicle made with a carbeurator in 1986, and the same vehicle, with same engine, and a throttle-body injection unit in 1989, you'll see that the numbers clearly disagree. You'll also see that in every automotive enthusiast magazine will agree.

If you step backwards in time to the days of combat warfare, you'll see that in WW2, all those aerobatic combat aircraft used a Throttle Body Injection system. Back then, they didn't have the ability to use an electronic computer to control it... the pilot's brain was PART of that computer, a modulator circuit (tapped into the turbo-supercharger output (which varied depending on which type of boost system was utilized) varied fuel flow to compensate for manifold pressure, load, exhaust temperature and throttle setting. Instead of 'TBI', they refered to them as 'pressure carbeurators', because they did not utilize a gravity-float system... but apparently they weren't all that much of an enhancement because we lost that war on two fronts, right?

TBI is an order-of-magnitude more effective at precise management of fuel, and it will reliably do TWO things that a carbeurator can NOT do:

1) it will accurately meter fuel with the manifold pressure at ambient... meaning... ZERO VACUUM.

2) It requires NO VENTURI in order to function, therefore it will A) Flow considerably more air for a given throttle cross-section than a carbeurator and B) It will NOT develop frost due to Venturi Effect... there's no venturi, there's no venturi effect.

Codger wrote:

Seen several smart, (far too smart for their own good) types play around with these systems with negative consequences at the most inopportune times too. "FAFO" tends to fit well into the scenario. Everything is trial and error to successful achievements and the most unfortunate part is the $$$ involved to produce tangible results.

Apparently you're hanging out with guys who don't invest effort in reading service manuals and acquiring proper tools. There's lots of really excellent manuals out there... for anyone that wants to get their feet wet, a copy of "Chevrolet TPI & TBI Engine Swapping" by Jaguars That Run is an EXCELLENT primer on how the most widely used TBI system... notably, the TBI system in Joe's truck, and in my boat... work, and they work incredibly well... just like electronic ignition works very well.

This system has only a few necessary components- the TBI-220, an inline 15psi fuel pump, a fuel pump relay, a coolant temp sensor, and a Manifold Air Pressure sensor... a wiring harness for those, and the GM 7747 ECM. With these components, it will outperform every aspect of a carbeurated engine, just running in 'open loop' mode.

It will automatically purge air and prime, then start cold without touching the throttle, it will run nice and pull away smooth when cold... It will maintain the proper idle speed regardless of wether you're in Drive, Reverse, Park or Neutral (it has dedicated spark and fuel maps for both circumstances). Because it is a constant pressure/constant return flow system, It WILL NOT vapor-lock.

If one desires an even fancier setup, that will run better, an oxygen sensor installed downstream of the header collector will allow it to go 'closed loop' once EGT is high enough to get a proper O2 reading, and at that point, it will do what NO carb can do- It will adjust the mixture AND TIMING based on altitude, temperature, throttle position, throttle change velocity. Add a knock sensor module, and it will include detonation detection to prevent the engine from self-destructing when fuel is lousy, and advance it back up for more power when fuel is good.

One can do all the mechanical futzing they WANT... it makes no significant difference, but one CAN 'screw it up'... they can damage one of the critical sensors, screw up the system with bad grounds, broken wires, or poorly shielded ignition components, big radio transmitters, or lousy battery cables.

To truely change it's performance character, one must change the fuel and spark mapping, which is stored on a 24-series EPROM chip. Very hard to screw up, but using a Eprom emulator, one can sit in the passenger seat, see all the operating sensor data make all the tuning target adjustments they so desire... they can even add stuff like mixture control under boost or nitrous.

As far as tangible results, again, if they're not willing to invest time in reading the proper reference sources (most of which can be found online for free now), it doesn't matter if they're trying to program new channels into their TV, or change the blades on their electric shaver, they're not gonna do well... and if they can't manage that, they shouldn't be lifting the hood of ANY car newer than 1960. If all they're doing, is applying the FA, they're going to suffer drastic results on everything.

Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.

	This site is not affiliated with AGCO Inc., Duluth GA., Allis-Chalmers Co., Milwaukee, WI., or any surviving or related corporate entity. All trademarks remain the property of their respective owners. All information presented herein should be considered the result of an un-moderated public forum with no responsibility for its accuracy or usability assumed by the users and sponsors of this site or any corporate entity.
	The Forum	Parts and Services	Unofficial Allis Store	Tractor Shows	Serial Numbers	History