Fuel injection without computer?

Hi all, does anyone know if a tbi injector can be run with out a computer? maybe with a pulse modulator with a variable duty cycle? I know just enough electronics to be dangerous,hahaha. I am building a 1977 ford 351w to dow.I have a complete efi intake from a 1995 truck, and was wanting to use it as my air intake, and installing one injector for gasoline. Any thoughts or ideas are appreciated. AL

Good Morning Al F.
First though you will have to lay out just When and How much you want the gasoline to assist the woodgas.

Steve Unruh

thanks, Steve I thought maybe to run it off the tps already on the air intake , if possible ,but trying to figure what I would need between tps and injector. to make it dual fuel without having to go the whole computer route. even thought of all mechanical running elec. fuel pump with pwm. or rheostat to jet type nozzle. Al

Steve’s right, it depends on what you want. If you want it to be able to run 100% on gasoline, and have good response, fuel economy etc… you’re looking at a pretty sophisticated fuel map with several inputs. Probably should be looking at MegaSquirt.

If you just need a jolt of fuel to get you over the next hill, a very simple setup should do fine. Just set it up with a PWM to run 0-100% duty cycle, and twiddle the knob when you need some gas.

Personally I think having manual control over the injectors at idle would improve my Dakota’s cold starts. It always runs too rich, because of the computer’s long term fuel trim being out of whack. So I fiddle with the fuel pressure… could just as easily fiddle with a fuel injector.

O.K. Let me help you decide.
First what does the actual spark ignition IC piston engine want for fuel wether it be liquid or gaseous?
This understandings evolved from about 1870’s to mid-1940’s. Everything past that just been twiddling refinements for smoothing transitions, best economy and best emissions and such.
You can get this all out of Holley, Rochester, Weber carburtors hot-rod books. Hot-rod books on turbo-charging. Hot-rod books on fuel injections tuning.
Fomally there considered to be different fueling Modes.

Cold start Mode. From a cold starting up you MUST over fuel enrichen.
Liquid fuels much more so than gaseous fuels. The cold metals are actually quenching/inhibiting the surface combustion. Surface contact and near surface fuels doing nothing. Just getting pumped out unburned. You have to overfuel compensate no matter what.
Here on: double each one to really two for wether the engine is still cold or warmed up in it’s demanded fuel needs Modes:
Idle fuel Mode. LIttle fuel weight/volume needed.
Medium power/load Mode. Moderate fuel needs.
Full power mode. Maximum burnable/combustable fuel needs. Good place to gasoline woodgas fuel supplement to ease gasifier overheating.
Acceleration mode. Short term maximum fuel needs to transition as quickly as possible UP from one of those above to the the next. Liquid fuel carbs end up with transitions slots to tide over, in addition to pumping squirts for this. Gasious fuels are All the worst for Acceleration enriching. Great place for a squirt of gasoline.
Light load, best economy mode. “Lindbergh mode” “featherfooting” “egg peddling” “hyper-mileing” Fuel Enleaned out as far as can with still complete combustible fuel mix as possible. Woodgased no need for gasoline here unless a tiny woodgas system with Big engine. Then the woodgas IS actually the fuel supplementing system.
Decel mode. Can be complete fuel shut off. Can be back to idle levels of fuel still allowed. Depends on the engine system and engine useage. Backfireing. Emmisions. Engine dieing/stalling once slowed down. How quick, how smooth, you may want re-acceleration.

Al I could walk you through a stab and hold one button solution to any ONE of Some of these Modes.
Others literally an old V-8 gutted ignition distributor with it’s points chattering doing the TBI injector cycling (60’s Robert Bocsh D systems) with you either hand cranking that chatterer switching; engine pulley driving it. Or variable electric motor drive for any ONE of some of the other fuel needs Modes
It’s making ALL these theses different fuel modes work, from one other, smoothly and seamless, why the best pre-emissions liquid fuel carburetor systems got so very, very evolved sophisticated, mechanically complex to be so actual “smart”. The smartest with altitude compensating aneroid bellows enleaners. The more “programable” they were, the even more complex they were. Webers versus non-emisions S.U.'s
The 40’s, 50’s smart clever best German systems WERE mechanially fuel injected for gasoline. 50’s Chevy Corvette Rochester FI was a “mechanical” FI system. Robert Bosch CSI (continuous spray injection) was darn near non-electrical except for the fuel pump.
These ALL had to satisfly the actual IC piston engine demanded fuels modes needs.

What do you want this TBI add-on to do for you?

Steve Unruh


Very interesting idea. First thing that comes to mind is the intakes are to divided bank to bank so you would need at least 2 injectors. Second is the are designed for dry flow. OK with woodgas mixed before the throttle body, not sure how gasoline would do in them. I think I would look at using an old carbureted intake if I were to try something like this. Give you a lot more room to work with and get rid of the hangover on the passengers side and flow issues. Cleaning issues come to mind also from hearing Wayne talk about carburetors and TBI systems.


thanks steve, chris. marvin, the idea came when I saw a video of a home made injector tester,that changed the pulse ,and in turn increased or decreased the spray mist. I would like to be able to drive on gasoline or wood gas.can use an under carb system, but talk on here seems they don’t work well. Al

Oh I don’t know about the giving up completely in the idea just yet Al.
You seem to be willing to at least single point like TBInjectors level learn.
If you were a jim-craky carb tuning guy, very comfortable with that, that may be best to go that route with it’s limitations. Other here have, and are. Wayne Kieth himself for a number of years. Just stumble across a 2007 article hi-lighting him two pedal operating back in his 460 carbureted woodgas Ford. Worked. Still working for DougB.
WesK is very correct that that Ford 95 EFI intake is a left-right bank split. You will need two single point like TBInjrctors injectors.
Gasoline carburetor intakes and true TBI as both gasoline droplets carrying type needed heat and enough narrow velosity keeping up and turns and twists to keep the gasoline droplets held into air flow suspension. This SEFI one is an air-all-fall-in type. “Cold” log ram type manifold. Why the Ford trolle body has engine coolants lines to it - to HEAT it from freezing/icng up.
The aftermarket super high flow unheated carburated performance type suck big time for smooth year around daily street driving using here in my cold/wet. With a gasoline carb fuel droplet misting they becomes a “fair weather” Sunday afternoon garage queen.
Great maniflolding for air/and warmed woodgas mix though!
If you were a carb guy try just sticking a small car side draft sub-carb on this 95 SEFI and try it. Get that tuned-in for easy starting up, idling, in and out of garage trundling not worth gasifier firing and warming up. DutchJohn did this on his Chev C-20. Then be done it. A no electronics needing to add, or learn solution. Use the 77 block fuel pump. Or a cheap for carburetor electric.

Even though I am real comfortable with EFI and TBI to do this would mean a dedicated EFI electric higher pressure fuel pump, high pressure fuel filter, higher pressure rated EFI rubber at all the flex areas, adding a return fuel line for the now must have fuel pressure regulator just to get started before any injectors pulse controlling.
Ha! Factory single points TBI system truck (GM & Dodge) you get all of this included free!
And WITH the factory sensors wiring harness and computer for the single points TBI too.
Then woodgas/gasoline TBI would be easy, and make sense.

The guys woodgasing the later sequential port electronic fuel injection rigs like the 95 was don’t have to learn any elecronics to do this.
Just like owning/operating any of these when just gasoline driven you only have to know enough to make it work.
Only have to learn more about the EFI system IF You want to repair it when it doesn’t work. This is only 10’s to a 100 hours now with the Internet to learn your own factory EFI system.

Throw mods to it. Expect shop auto techs to charge you more to learn/tune in for your mod choices. 3X to 5X the cost or push it back out the door and go away. I last pushed out a 2005 P.T. Cruiser with an in California added on belt driven super charger, with check engine light mis-fires, then unable to emissions test. I wasn’t interested in taking his money.
Take it to a tuner shop and pay the 5X up front.
To really begin know well carburetors, TBI systems and EFI systems is to invest a beginning 500 hours in yourself. Work on yours, and all family and friends, different systems when they are having problems. Constanly going back and looking up the diffenrt systems types, thier strength and weaknesses. Along about 2000 hour of this self-teaching you will no longer be accounting for the time invested in yourself anymore. Groan at the special project bolt-on’s: “Now you make it work for me please???”

Actually nothing really special unique about carburetion and EFI learning.
Takes that same 2000 hours of combo reading/doing self-investment to begin to make a good shop welder person, commercial head baker, good able to do-all fry cook, modern farmer, and most any all skilled trades people anymore.
Just depends on where, and how you want to invest in yourself.

Gasifier operating takes this same commitment of a hunderd or so min operating hours too. No shortcuts. Fellow only start to get good all-systems after about 1000 operating hours.
Ha! Always know them. They know when to drop and run away. Know to always face away from freshly opened up hoppers. Stand behind the hinged side of hinged lids. Hang on tight to the loose lids and use them as shields. “That wood will be too wet” Nagging, “Somethings not quite right” Sounds. Smells. Felt heats.
All skills have a soul searching commitment demanded time hurdle to pass to ever become good.

Your old’un Ford can be the woodgas beginning of this however you do this. ONCE you do get it woodgas running in any way.
Look at Dustin Moores truck. Get it going. Later Upgrade it then.

Steve Unruh

thanks Steve, I agree 100% invest in your self, I have for 50 plus yrs. never hired any work done always did myself , not enough people now days want to do this. My project to dow. is a 1948 ford f-1. Rebuilding the 351 for it. I am retired now have the time for these fun projects. Al

Great to hear this Al
Yep. I’ve paid for very, very little service work on anything myself life time.
Ha! The price at times to learn has been having to redo over sometimes 2-3 times for learning OOP’es.
2nd time do over for a clothes dryer heater element. Needed to actually fix a drum seal to keep the shorting penny’s out!
TWO hot water heaters split and cracked, leaking 'cause back when I originally installed we were in well water WITH an air bladder pressure tank. Gov’mint Forced/Mandated onto Town water thier anti-back flow valve was trapping my system into 100 PSI house system spikng after me and the wife would hot water useage dump out and it would cold water re-heat.
Needed to have added in a air charged high point expantion tank above the hot water tank. I’m a Rural boy. Not a townie always been on municipal just blindly following codes.
My mistakes always been affordable for the why understandings.

For your project truck the easiest to understand fuel injection primers are the HP series of fuel injection systems hot-rod books. Give you basic understanding needs. Focus on the Ford systems. Shortest route to the goal would be a clapped out rust bucket say early V-8 Ford Explorer. Noboby wants to restore or maintain these. Overlooked parts gems. You bone out all of the FI system components. Every damn thing. Tank with pump, hoses, wiring harnesses, computer, harnesses right up to the engine sensors including the sensor and plugs, the works. Floor lay this all out; untape all of the harnesses. Using the HP books as guide remove all wiring NOT needed to just make the FI system work. Double back and retape up too long of leg sections into your chassis install. Then ONLY center leg extend out too short of wiring legs.
As an old been retored now much painted up chassis - any place there was factory to the Exploder grounding harness eyelets bolt connect your own made up grounding wires back to the battery negative. Treat it like a wooden or fiberglass boat.
Then you can just all “book”, Internet users club, Exploder FI diagnosis and repair as needed.

Al the trick I’ve found in an increasing electronified world to sanely handle electronics is TOO NOT DETAIL LEARN THEM. You will go blind, your teeth will rot and you will become a caffeine junkie.
Any electronics component has to have Inputs to generated Outputs.
Your only concern is really are you doing the job for me I need to get to My Goal.
IF I can verify POSITIVLY that I’ve supplied you with all of your needed imputs, and you still aint’ willing to output . . . you goona’ get shipped and slaughtered just like any underperforming pig, chicken or cow.
I learned to apply the same decision tree serious farm used on electronic alternator voltage regulators back in the late 1960’s. Carried on that same to electronic ignitions in the 70’s. Then that onto fuel injection 80’s and on. Works good for your own stuff.

This laptop I’m on now better at least do as good of job for me word scribing as a set-aside electric typewriter.
Cell phone actually has to work as well as the old corded phones.
Any increased benifits electronified is just frostings. I still demand real cake.
Never, ever, do I let the gee-whiss of “elecronics” wow me past the fact that my needs/goals were being met and achieved in a pre-digetal world.
I the Dog - they the tail. Serve me well. Or get cut off.

Steve Unruh