2.9 injector pressure rating

[Crash_X]

Shopping for injectors for my 1990, 2.9.
Seeing a lot of different lbs ratings.
I dont know what to get.
Thanks all

 

[RonD]

2.9l and 4.0l OHV were 14lbs/hour, 15 will work as well, 19lb/hr would set Rich codes

Injectors are all rated at 43.5psi fuel pressure, your Ranger(all Rangers) ran 35psi thru 1997, then it change to 60psi
Motorcraft rates their injectors at 39psi, lol

But pressure doesn't matter that much unless its way too low or way too high, fuel pump is capable of 80+psi if unregulated

Injectors should only run at 80% capacity at Wide Open Throttle(WOT)

Rule of thumb for non-turbo engine, use 1/2 the rated horse power, in this case 70hp is 1/2 of 140hp
Multiply the number of injectors by 80%, so in this case 6 X 0.80 = 4.8
Then divide 70 by 4.8 = 14.58lb/hour needed using 43psi, +/-10psi won't matter, and thats at 80% of injectors capacity


The computer is programmed for the engine size and size of injectors, also the fuel pressure, there was never a fuel pressure sensor on Rangers
So computer "knows" how much fuel will flow out of 1 injector if it is opened for say 100ms(milliseconds), and that is used to calculate open time for each injector for correct air:fuel mix
If you put in 19lb/hr, or 24lb/hr then computers calculation would be off, too much fuel is flowing out for that 100ms, so computer has to cut down the open time of each injector, and when it does that by more than 20% you get Rich Codes

Injectors are not the same as Jets on a carb, bigger does not make more power, just throws off computers air/fuel calculations

 

[Crash_X]

2.9l and 4.0l OHV were 14lbs/hour, 15 will work as well, 19lb/hr would set Rich codes

Injectors are all rated at 43.5psi fuel pressure, your Ranger(all Rangers) ran 35psi thru 1997, then it change to 60psi
Motorcraft rates their injectors at 39psi, lol

But pressure doesn't matter that much unless its way too low or way too high, fuel pump is capable of 80+psi if unregulated

Injectors should only run at 80% capacity at Wide Open Throttle(WOT)

Rule of thumb for non-turbo engine, use 1/2 the rated horse power, in this case 70hp is 1/2 of 140hp
Multiply the number of injectors by 80%, so in this case 6 X 0.80 = 4.8
Then divide 70 by 4.8 = 14.58lb/hour needed using 43psi, +/-10psi won't matter, and thats at 80% of injectors capacity


The computer is programmed for the engine size and size of injectors, also the fuel pressure, there was never a fuel pressure sensor on Rangers
So computer "knows" how much fuel will flow out of 1 injector if it is opened for say 100ms(milliseconds), and that is used to calculate open time for each injector for correct air:fuel mix
If you put in 19lb/hr, or 24lb/hr then computers calculation would be off, too much fuel is flowing out for that 100ms, so computer has to cut down the open time of each injector, and when it does that by more than 20% you get Rich Codes

Injectors are not the same as Jets on a carb, bigger does not make more power, just throws off computers air/fuel calculations

Thank you RonD
I was hoping you would comment and teach.
Exactly what I needed