Hi there, I have the following problem with my car: when I start it the RPM's begin to fall rapidly and when they are around 1500rpm there is a specific click sound like from a relay. The car starts to lose power and starts to rattle a lot. When I start some of the electricity consumer like headlights, horn or heating the car rattles again and drops RPM's.
The car is a 5th generation CIvic VTi with a swaped GSR engine and OBD1. This happens only when I drive the car with the additional ECU chip. The car has a P30 ECU. When it works with the factory tuning (chip) it works normal, not having this problem. I have tried a few aftermarket ECU chips but the result is the same. It works fine only with the factory chip. I have made an external switch so I can switch between the factory and aftermarket chips without opening the ECU each time.

Any advice or suggestion is welcome!
Thank You!