2.3L Ford EFI Modifications - Fuel Injectors!
The stock fuel injector for a 1992 Ford Ranger is rated at 14 lb/hr. You can swap in a better flowing fuel injector for better performance. I have been working on increasing the air flow through the engine and consequently, I should increase the fuel flow appropriately.
I just returned from a 3000 mile (5000 km) 4 day road trip to Santa Fe New Mexico pulling a 1300 lb trailer. When you are behind the steering wheel for 55 hours, you notice some things. One thing I noticed was that when I was going up a steep hill with my foot to the floor, I could slowly back off the gas pedal without slowing down. At one point, the truck would sometimes actually accelerate!
This got me thinking. If I have the pedal to the floor, the butterflies on the fuel injection are wide open and I'm getting as much air as the engine can handle. If I back off the gas pedal, the butterflies are closing and less air is allowed in. If the truck starts accelerating when backing off the gas pedal, that means that we're getting the ideal fuel/air mixture and the most power. At wide open throttle the engine is not getting enough fuel - the fuel injectors can't supply enough fuel. I need bigger fuel injectors!
I tried a little experiment. I figured that wiith my foot to the floor on the hills, the engine was running lean (not enough fuel). So whenever, I started up a hill with my foot to the floor, I slowly feathered the gas pedal back until the truck started slowing down, then pressed on the pedal til it just maintained speed. Doing that I managed my best gas mileage for the trip of 27.5 mpg versus 23 to 25 for the rest of the trip.
This webpage called Choosing the Correct Fuel Injector for your Application (which is taken from the Accel performance fuel injector data sheets - linked below) has the mathematics for selecting a fuel injector based on your hp requirements.
I ran the 2.3L specifications through the magic formulas and used BSFC of 0.45, number of injectors = 4 and a duty cycle of 0.80 for a 100 hp engine. They indicated that I would need a stock 14 lb/hr fuel injector. If I wanted 130 hp from the engine, using the same BSFC and duty cycle, I would need an 18.3 lb/hr flow rating. Obviously, the flow rating of the stock fuel injectors is limiting the amount of hp the engine can produce.
I ran across the Accel performance fuel injector data sheets (pdf) and they list 3 fuel injectors for the 2.3L Ford engine:
- 14 lb/hr for stock replacement
- 15 lb/hr for Level 1 performance
- 17 lb/hr for Level 2 performance
Unfortunately, they don't expand on what they mean by Level 1 and 2 performance. This leads to my research, I've found that you cannot just slap on any old higher output fuel injector and expect it to work. The size of the fuel injector and the mass air flow sensor should be matched together within the limits of the computer's (MCU) programming. If you replace any of the components and they are out of the limits of the MCU's programming, you will end up with a poorly performing engine.
From my research, there should be no problem in upgrading to a 15 lb/hr fuel injector without reprogramming the MCU. Now interestingly with the Accel fuel injector data sheets, it limits the available fuel injector flow rate to a maximum of 17 lb/hr. Why only 17 lb/hr and not higher as in the other engines Level 3 to 9 injectors? (Yes other engines have up to 9 levels of performance injectors!) This leads me to believe that the maximum flow rate that is within the MCU's programming limits is 17 lb/hr without changing any other component.
Level 1 - 15 lb/hr fuel injector sources
15 lb/hr from one of the following 2.3L engines:
- 95-97 Ford Ranger/Mazda B2300
- 91-93 Mustang 2.3L
- 92-96 Ford Escort Tracer 1.9L
- 89-94 Taurus, Sable 3.8L
- 91-95 Thunderbird 3.8L
This should give you 7% increase in fuel to the engine and hopefully 7% more power! I haven't done this yet but expect about 7 to 10 more hp at WOT (wide open throttle) which I use going up hills (I live next to the Rockies).
Level 2 - 17 lb/hr fuel injector sources
There are no Ford products that use the 17 lb/hr fuel injectors as stock parts, Ford jumps up to the next size which is 19 lb/hr. But the same Accel 17 lb/hr fuel injector is listed as stock replacements for the following GM products:
- 94-98 Achiva, Ciera 3.1L
- 93-95 Camaro, Firebird 3.4L
- 93-97 Cutlass Supreme 3.1L
- 97-98 Cutlass 3.1L
- 94-98 Century, Regal, Skylark 3.1L
- 94-96 Corsica, Beretta 3.1L
- 94-99 Grand Prix, Grand Am 3.1L
- 95-99 Lumina, Monte Carlo 3.1L
- 97-99 Malibu 3.1L
With a Stage 2 fuel injector, I would expect 21% better fuel flow over the stock 14 lb/hr fuel injectors. Hopefully, this would translate into a 21% increase in available horsepower or roughly an increase of 21 hp!
How to swap out a fuel injector
Here is a page that gives some tips on swapping out the fuel injectors
Tips and Tricks
If you have some tips and tricks that squeeze a little more power out of your 2.3L Ford and you want to share them, contact me at:
