Have a 1998 Civic Dx that i recently swaped a OBD1 B18b1 motor with Si transmission. Motor was rebuilt with new gaskets, seals, pistons, rings, etc. Nothing done to top end besides seals. Using a 98 civic dx wiring harness with obd2 ls ecu. Converted motor over to OBD2...Injectors, distributor, oil pump with crank position sensor, and IACV. I have fuel, spark, and compression. 135,130,125,140 readings on the compression check. Only able to get it to back fire. Any ideas on what might be causeing it not to crank????