1989 Mustang Gt A9l Computer Question

The 89 Mustang 5.0 came as mass air as standard, and the A9L Mass Air computer was the standard computer in them.

The 88 and 89 engines are identical in terms of what sensors are on them and how they connect to the computer. The 10 pin connection is the same on both engines.

See the graphic for the 10 pin connector circuit layout.


A larger MAF for your new engine would be a good thing...
94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. This is a direct one for one swap that does not require any tuning or programming, It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes. *1 *2
*1.) Metal flange adapter http://www.kustomz.com/components.html Buy the TR70 for $40. Or spend some time on eBay looking for one that may fit.

*2.) MAF & sensor interchange
The 94-95 Mustang 5.0 MAF & sensor is also found on:
1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.

Source. A maf from a 94/5 ft from the jy. The rest like jrichker said is plug and play. Fwiw I have an 89 harness in my converted 87 and have no issues.