Traced down a fail-to-start problem (thanks to info obtained from Stangnet.com) to a computer failure on my '92 GT, VIN 1FACP45E0NF114479, automatic trans. convertible. Replaced the failed unit, EEC-IV SF1-MA12A, A9P, E9ZF-12A650-CA with a unit salvaged from an '89 GT with automatic transmission, EEC-IV, SF1-MA12, A9P, E9ZF-12A650-C2A. The failed unit was equipped with an aftermarket ADS Super Chip performance module and what appears to be a stock Hypertech Power Module. The salvaged unit has no enhancements. The reason I believe the Hypertech Module to be stock is that it bears a '92 date. The car started immediately when the salvaged unit was installed and seems to run OK. However, before I finalize the deal with the salvage yard I would like to know if the two units are completely interchangeable. The slight differences in the model numbers indicates that there may be a difference between the two. Would also like to know what the ADS Superchip and the Hypertech Power module do for the engine's performance and should I consider installing similar enhancements on the replacement unit. ANY ADVICE IS GREATLY APPRECIATED.
Computer Swap
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Copied from Steve89GT
"There are a few different varieties of computers... just a few different calibrations.. Here's the #'s of most of the MAF computers that are around. A9L and A9P are the most common.
1989 MANUAL A9L, A9S
1989 AUTO A9P, A9T
1990-92 MANUAL A9L
1990-92 AUTO A9P
1993 MANUAL A3M
1993 AUTO C3W
1993 COBRA X3Z "
End of copied text
The computers are interchangeable. The most important part number is the A9P, which is an auto trans 5.0 Mustang code.
The aftermarket chip is probably a waste of time and effort. There is very little that they do other than provide some more spark advance. A little effort with a timing light can accomplish the same thing.
Most add on chips will set code 15, which is a computer failure code. They modify the computer's program so that the internal diagnostic checksum fails, and that sets the code 15. Disconnect the battery lead and remove the add on chip, then when you power it all back up, the code 15 is gone.
"There are a few different varieties of computers... just a few different calibrations.. Here's the #'s of most of the MAF computers that are around. A9L and A9P are the most common.
1989 MANUAL A9L, A9S
1989 AUTO A9P, A9T
1990-92 MANUAL A9L
1990-92 AUTO A9P
1993 MANUAL A3M
1993 AUTO C3W
1993 COBRA X3Z "
End of copied text
The computers are interchangeable. The most important part number is the A9P, which is an auto trans 5.0 Mustang code.
The aftermarket chip is probably a waste of time and effort. There is very little that they do other than provide some more spark advance. A little effort with a timing light can accomplish the same thing.
Most add on chips will set code 15, which is a computer failure code. They modify the computer's program so that the internal diagnostic checksum fails, and that sets the code 15. Disconnect the battery lead and remove the add on chip, then when you power it all back up, the code 15 is gone.
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