Hello I recently just swapped a b20z block and a b16 vtec head into my 1993 eg hatchback. The car had been previously b swapped with a b20b block and the same head. It has the same chipped p28 ecu. The only thing I’ve changed is the injectors valve springs and that’s about it. The problem is when it starts it idles at high rpm’s around 3,000-2800. Sometimes the rpm’s bounce too. I diagnosed vacuum leaks and all checks out. The only thing I can think of is the tune. I have the cord to plug into the ecu but will I be able to upload a tune or will I need a new chip? I’m not sure about any of it. Please help I’m very new to this. Thank you in advance-Mike

 

Was the old block a low compression B20B?