Question about my friends car
 

My friend has a 98 honda prelude ( i know its not an accord but i just wanted to ask this question to make sure i'm giving him the right advice) and he just got the engine swapped for a new h22a4 engine that is suppost to be imported from japan. The engine got put in and now the car will not turn on at all. The mechanic that put it in for him said that the key will not turn in the ignition. So i told him it sounds like he needs to reprogram the ecu to work with the new engine...am i right or is something else wrong? Any advice will be helpful, Thank you

Unless he changed the ECU, it should start and run. ECU doesn't know difference between one engine or another.

good luck

The key mismatched to the ECU, or ECU mismatched to engine, or engine swapped, or anything like that... WILL NOT prevent the key from turning in the ignition. Is he trying the key for the wrong car?

If you swap the ECU and the immobilizer doesn't recognize the key, then the engine won't start. But the key will turn.

The ECU actually DOES know one engine from another, in some respects. Every so often, Honda changes the timing sensors around and/or changes the nature of the signals from those sensors.

So I don't know what engine was originally in his Prelude, and I also don't know what range of years was covered by the H22A4. But a different year can still be incompatible.

He also orginally had a h22a4 engine in his prelude and i was thinking the same thing that the car should have started up since its the same engine type so now we are having trouble finding out what the problem is

All the lights and fuel pump come on as usual? Starter hooked up right?

What I'm saying is "H22A4" isn't enough information. Sometimes the sensors aren't the same between certain years.