here is what is happening everytime i start the car, the motor will turn over and start but suddenly stop. i have a check engine light it says that i have a IACV mulfunction but the thing is that i check for voltage at the connector of the IACV and i am getting only .5 volts. the next thing i did was look for a connection between the pin coming out of the ECU and the IACV connector it-self and i have a good connection. i also try putting 12 volts strianght to the IACV. once i do that the motor starts, it runs but does not idle every good. the motor will stay at 1500rpm and spudder. the motor will rev over 3500rpm with a little bit of spuddering at low rpm but once it is over 2000rpm it good. i know that the spuddering is coming from the fact that IACV is open all the way so the ECU can not compensate for the air that is coming in to the motor but i dont know what to do anymore. also i tried checking the MAP sensor and it seems to be working because i swapped out my d series MAP with the gs-r one and nothing changes

here is what iam using
97 ex harness
motor:b18c1 98 spec with p72 ECU
car: 97 civic hatch

 

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I would consider replacing the IAC valve. Is that the only check engine light?

When we did the B16 swap it started and died, about 3 times and would not start. The coil was bad. I would start by swapping your D series coil into the b18 and replacing the iac valve.