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Q: Car will start but will not stay on

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I have a wrecked 96 4.6 auto Ford Mustang, I just put the motor in a 98 4.6 manual body the car will start but will not stay on. Mechanic took to dealership for programming, They said they could not due to wiring. What could be the problem? My mechanic is telling me that the 96 motor and 96 computer will not work in the 98 body and wants me to get a 98 computer. He is using the 98 key. At this point, I am confused.
My car has an automatic transmission.

A: Hi there; I can understand your frustratio...

Hi there;

I can understand your frustration, but to break it down simply; the electrical components (including wiring, relays and the ECU) on a 98 Mustang are not 100% compatible with the 96 engine system. When you swap motors, you need to ensure that the programming module is current to the vehicle year (not the motor). So, in this case, you need to have a 98 Mustang V8 4.6 liter ECU, and have it reprogrammed to link with your 96 motor. When automotive manufacturers started doing this in the early 90’s, it pretty much made swapping motors incredibly difficult for the hard working mechanic. However if you want the motor to work with that 98 Mustang, that’s the only way to make it work correctly.

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