93 Mustang Computer Help

What is done to the car ?

The A9L is the most popular replacement. If it's working, keep it.
A3M1

X3Z

If it runs good with the a9l I’d leave it.

looks like the stock intake to me with the plate up top could be wrong tho. And the one computer looks like it has the Bama chip

That is a chip in the cobra computer. Your engine looks to have the stock orange color injectors though. The cobra computer is for 24lb blue injectors. The chip should pull straight out....maybe it has the make on it.

I see no injectors & the chip is in the X3Z computer (Cobra). Looks like the chip is a BAMA.

90sickfox said:

That is a chip in the cobra computer. Your engine looks to have the stock orange color injectors though. The cobra computer is for 24lb blue injectors. The chip should pull straight out....maybe it has the make on it.

Click to expand...

Ford did the reasonable thing -rather than add a part or parts, they modified the X3Z firmware for the soldered into the board chip to work with a different MAF and 24 lb. injectors. The piggyback add-on device isn't part of the original equipment that came with the computer.

JRichker is correct. The X3Z came on the 93 cobra specifically, whereas the others were for the other Mass Air fox body cars. In stock form (no chip or custom tuning), the X3Z should ONLY be used if you specifically have the injectors and mass air from the 93 cobra... not just any 24 lb setup. In the X3Z calibration, Ford did something a bit strange that stands out from the rest of the Mass Air computer calibrations. On the injector data, Ford uses a Two-Slope characterization of fuel injectors: a High and a Low slope. The high slope is supposed to represent the "rated" flow of the fuel injector, assuming it's run at the "rated" fuel pressure. But it seems injectors aren't completely linear. At lower pulsewidths, the injectors behave differently and generally flow more fuel than expected... speaking in relation to what you get out of the injectors during higher pulsewidths. So in this two slope system you put in both numbers, then specify a breakpoint at which the injector transitions from the low to high slope.

So back to why not any 24 lb injectors/maf on the X3Z? Well ford set the high and low slopes in that calibration to the same value. That means they had to hack around with the MAF curve in an attempt to get the fueling correct, which in turn means they had to recalibrate other things in the tune based on the change in reported Load this will create. Most of the calibrated MAFs out there are aligned much more to the factory MAF curve with the non-cobra computers originally designed for 19 lb injectors. So if you put some random 24 lb calibrated mad and injectors in the car, don't expect good results. I recently tuned a car for a friend locally. He was using those cobra injectors, but with a third-party MAF for 24 lb injectors. His car is not a cobra and uses an A9P computer. When i plugged in the same injector data used in the cobra calibration, the car's fueling was off by around 20% in several areas. Obviously we could easily deal with all that in the tune. but without a custom tune, this was disaster for the car. It was in very rough shape.

So what do I ultimately recommend here? Well, since you have three computers that will technically work for mass air cars, you first need to figure out what injectors and maf that you have now. If stock 19 lb stuff, go with the A9L or A3M1, as they are virtually identical. In this case, without question open them up and see which is in better conditions. Look for burnt tracers or leaking/swollen caps. Those are the two main issues people have with these. Also check the condition of all the pins. Should all be present and not bent. If it's stock cobra stuff go with the X3Z.

If you have any other combination and are going to have the car tuned with a piggyback chip like the one you also have (but there are others out there as well), then all three computers will support the same settings. So now, you would want to pick the best condition out of the three, then put your chip tune on and run with it. Hope this helps you make the decision as to which of your 3 computers will be the best fit for your application. Feel free to message me any time if you'd like to hop on the phone and discuss the specifics of your build. Cheers. -Matt