* Incorrect Crankshaft Position Sensor (CKP) signal: The CKP sensor tells the engine control unit (ECU) the position of the crankshaft, crucial for timing fuel injection and ignition. A misaligned sensor, a faulty sensor, or a wiring problem could cause the engine to run erratically or cut out, especially under load (when you give it gas). This is a very common issue after an engine swap.
* Improperly installed or faulty camshaft position sensor (CMP) sensor: Similar to the CKP sensor, a problem with the CMP sensor will lead to incorrect timing and erratic running.
* Throttle Position Sensor (TPS) issue: A faulty TPS doesn't accurately tell the ECU how much the throttle is open. This can cause incorrect fuel delivery, leading to stalling or cutting out, particularly when you accelerate.
* Airflow Meter (MAF) sensor problem: The MAF sensor measures the amount of air entering the engine. A faulty MAF sensor will lead to incorrect fuel/air mixture calculations, resulting in rough running or stalling.
* Fuel pressure issues: Though you haven't changed the fuel system, ensure the fuel pressure is correct. A low pressure or inconsistent pressure will cause the engine to sputter and die. This could be related to a blocked fuel filter or a faulty fuel pump.
* Wiring harness issues: During the engine swap, wires may have been damaged, disconnected, or incorrectly connected. This is a major culprit. Double-check all wiring connections, especially those related to the sensors mentioned above. Look for damaged insulation or shorts.
* ECU calibration: The ECU might be calibrated for the old engine. If the new engine has different specifications (displacement, compression ratio, etc.), the ECU's fuel map might be incorrect, leading to poor running or stalling. You might need to have the ECU reprogrammed or tuned for the new engine.
* Immobilizer system: If the car has an immobilizer, and the key isn't properly recognized by the system, the engine might start but cut off after a short time.
Troubleshooting Steps:
1. Check for error codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the ECU. This will give you valuable clues.
2. Verify all sensor connections: Carefully inspect all sensor connections for damage or corrosion.
3. Check fuel pressure: Use a fuel pressure gauge to verify the fuel pressure is within the manufacturer's specifications.
4. Inspect wiring harness: Meticulously check all wiring connections related to the engine and fuel system. Look for any breaks, shorts, or loose connections.
5. Confirm correct sensor installation: Make sure all sensors (CKP, CMP, TPS, MAF) are correctly installed and aligned.
6. Consider professional help: If you are not experienced with automotive repair, it's best to seek the help of a qualified mechanic to diagnose and fix the issue. An engine swap is complex, and missing a small detail can lead to major problems.
The problem is likely related to the interaction between the new engine and the existing fuel injection system. A systematic check of sensors and wiring is the best approach.
