I have a 94 t-bird with a 1990 3.8 engine that I installed and modified along with a 1993 transmission. I swapped out the main harness along with the vacuum harnesses and vacuum line assemblies. I also had to change the alternator harness and oil pressure sensor wiring. Last but not least the two trans mission harness were changed as well.
Everything works but heres the problem, when I turn the key the car motor turns and turns but will not start just acts like it wants to start but won't. Around the time I first finished completely modifying everything I could think to swap out. The car would start after about 10 trys’ would cut it and it would start right back up with no problems as long as the motor was warm. Motor cools off no start until many try’s. It’s been 5 months and now the car dose not start at all no matter how many try’s in turning the engine over. The car attempts to start but won't. Car has fuel pressure and spark, although I have not checked for how much psi pressure or resistance (don’t have the test equipment to do so). I am ready to call it quits but before I do wanted to ask for your opinion on weather I should change the engine computer from the year of the car (1994) to the year of the new engine (1990)