Widebodycoupe

Hi guys, yes this is another IAC question and I am sorry, but I have searched and I have not yet seen anyone post anything about checking the continuety in the IAC valve. I swapped a 94' JDM B18C into my 95' Civic Coupe, and ever since, the engine light is on. I have changed my IAC valve, cleared the computer and still the engine light is on. I have cleaned the IAC and still nothing. I have checked the voltage in the IAC harness and it says 5.7V. Shouldn't I have at least 12V? I have also checked for continuety in the IAC plug and there IS continuety and I don't believe there should be. My idle is between 1000rmp and 2400rpms, my fuel economy is terrible, and I am always running rich according to my A/F guage. Someone PLEASE help! Thanks in advance.
Peace,
Jeff

Honda Tech

ok, so yes you are right, the volts are wrong. you should have battery voltage going to the IAC, (on your civic wiring harness it should have 2 wires, one wire will be yellow and black and other will be blue and yellow)
so if you only have 5. whatever volts there, you have to repair an open in the yellow/black wire between the IAC and the PGM-FI main relay.
so, hopefully the open is within the engine bay, because thats a long wire, with your knowledge so far, I think u know where the main relay is, if not I have pics that can help, I just don't know how to post them so if you know that then let me know how and I will post the pics for u.
cheers and let me know how it goes. :thumbsup:

Widebodycoupe

Hey bro, thanks for the advice. The main relay is under the drivers side dash and it is a large grey harness, right? I tried to check for continuety from the IAC valve harness to the large harness in the engine bay on the passenger side right before it goes through the firewall. Then I checked for continuety from that harness to the main relay and there is continuety to there. Today I cleaned the IAC valve out with carb cleaner and Simple Green. Got out all the carbon deposits and other crud. Also, I took apart my throttle body, cleaned it out and took apart the FITV valve and tightened the white screw. I then put it all back together and cleared the ECU. and my check engine light is still lit up??? One thing I did notice, is my intake manifold is FULL of black oily crap!!! and I mean alot of it. I don't know, this engine light thing is driving me nuts!! Any info would be greatly appreciated. Thanks in advance.
Peace,
Jeff

Honda Tech

no prob dude, but ya, the main relay is under the driverside dash, also check voltage at main relay, in and out, both should be battery voltage. pic attached. then check that yellow and black power wire going to the IAC, if you can't find a problem with it in the engine bay, your other option is cut wire a couple of inches away from the IAC, and attach IAC power wire (ylw/blk) to a new wire (about 5ft of 16 gauge wire) and run it to the original power source wire running out of main relay, (ylw/blk), pic attached.

so in short make new power wire, and leave a little slack here and there, just incase.

Widebodycoupe

Hey there dude, thanks for the info. After checking all the wires from the IAC to the ECU, to the main relay, I discovered that there was 12v from the relay going into the ecu. But when I tested for voltage, there was 12+volts going into the ecu and only 6+ volts coming out of it. So I did what you said and ran a wire directly from the main power on the relay to the IAC. When I started the engine, the idle was TERRIBLE! Jumping all over the place. After letting it warm to normal operating temp, I unplugged the IAC and the idle dropped from about 2000 to about 750 and it ran smooth. I cleaned the IAC valve and tightened the white "screw" on the fitv and still nothing changed. What do you think. Thanks in advance bro.
Peace,
Jeff

Honda Tech

ok, well lets go back to the beginning and look at the 14 code. e-mail me and I will send u a procedure list to go thro.

Widebodycoupe

Hey bro, how are ya? I diagnosed it again, and the codes are now coming up:
1 long blink*
1 long blink*

1 long blink*

1 long, 4 short*
So I don't know what up??