I worked on a 95 F-250 today and just for kicks I looked at the emission sticker on the hood. I noticed instead of MFI like my 91 it had SFI which translates into Sequential Fuel Injection. The truck did not have a Mass air senor and still had the OBDI connector. My question is if I could possibly swap computers so that I would have SFI instead of the peasky MFI with the slight miss bcause the injectors are fired by bank. The trucks are both equipped with the 460 motor.

My only concern that maybe the harnesses are slightly different?

 

Have you found out anything more about this MFI vs SFI? I have a 91F250 302 that sounds like a miss at idle but I can't find anything wrong with it.

 

FYI...SFI requires 9 injector wires from the computer.. 1 for each squirter plus a common ground, while batch fire only uses 3 wires. You would have to add all these wires or find an SFI engine harness.

 

I just got a 94F150 and it has mass air flow sensor and idles as smooth as silk. It must have SFI.

 

Yes.. all Ford mass air motors use sequential injection.

 

I am assuming the injectors are 19 Lb/hr. What happens if I put say, 17 Lb/hr. injectors in it? Will the computer adapt and just lengthen the pulse width 10% or will it be forced to run lean. I want to be able to run as lean as 16 to 1 under light load. Is there a better way like variable voltage to the fuel pump? Have you played with lean burn?

 

You have 24lb injectors on a 460, they have a blue body. If you want to get the motor to run lean the best solution I have seen is an adjustable wideband O2 sensor like this one. LC-1 Lambda Cable with 02 Sensor : Wideband Controller Cable for Dyno, ECU, Data Acquisition, or Gauge Applications. I have this kit for tuning purposes on the 5.8 motor I'm building, but I used it to diagnose a problem I was having with the 5.0. The Kit provides an analog output that simulates the factory narrow band O2 sensor, and you can change the A/F ratio at which the sensor switches. I tried this on my truck and it works great, the motor ran perfectly using the input from the kit and obtained the programmed A/F ratio as soon as it went closed loop. This is really the only way to get the motor to operate leaner than it normally would, all the programming inside the computer is based around lambda of 1, which equals 14.7:1 A/F ratio, which is where all narrow band O2 sensors are designed to switch from low to high. So the computer doesn't know what the actual A/F is, it only really knows to go rich or lean from the baseline based on input from the O2 sensor. So if you substitue a sensor that switches at 15 or 16:1 the computer will use all it's built-in processes to adjust to that ratio.

 

Both of mine are 302's so probably 19Lb/hr. Is the $199 kit the one your talking about?

 

Oh sorry... I now see you're not the one who started this thread. Yes.. the small V8's used 19lb(yellow) injectors, and yes I was talking about the LC-1 Kit
http://www.innovatemotorsports.com/x...cat=262&page=1