My brother just swapped a JDM D15B OBDII engine into his 98 Civic EX. He swapped over the D16Y8 fuel rail, Skunk2 intake manifold with the D16Y8 injectors, and a DC 4-1 header. He is running the stock EX ECU because he was told he would be able to use it.

The JDM engine has a 3 stage VTEC with 2 VTEC solenoids. From what we believe, the first solenoid switches the engine to run from 12 to 16 valves and the second one is the regular VTEC solenoid which operates the pressure activated dowel. Basically the engine runs in 3 stages; 12 valve no VTEC, 16 valve no VTEC, and 16 valve VTEC.

When he rewired the VTEC connector, he wired it so the engine would always be in 16 valve mode, eliminating the 12 valve duration. The problem is that when he runs it in 12 valve mode, it idles fine but when he runs 16 valve mode it idles like trash. He is also getting misfire codes in cylinders 1-4.

Does anyone have any idea what our problem could be? Imput is appreciated. Thanks in advance.

 

well considering all the mix and match's you have I would have to say get it tuned first!