Long time lurker, first time posting.

So I just got done swapping heads and replacing the head gasket on my 2000 EX. While I was in there I replaced the timing belt, water pump, and tensioner. Also adjusted my valve lash. Car runs great except for an obvious, bad intake leak. The heads are of the exact same casting, same year model EX and everything. Donor car was an auto, as was mine used to be. Converted to 5 speed. My intake manifold was from a manual car (also a 2000) and I performed the 2-wire IACV conversion too. It should be a direct swap, so I don't suspect any compatibility issues.

The intake manifold gasket is an OEM unit I picked up from the dealer. When spraying starting fluid around the upper intake flange/injector ports the car bogs from 1500rpm to 600rpm. The injector o-rings are also brand new. The mating surfaces were clear of old gasket material. Torqued to 17lbs per the manual.

Question: would it be wise to lightly slather both sides of the gasket with hondabond? Or something? I didn't have this problem with my old head. Strange thing is, the deck mating surfaces were straight and square. As said the car runs great except for a bad idle and P0505, which I am assuming is being triggered by the leak. Any help or info is greatly appreciated.

 

P0505 is an open circuit in the IACV. You have to have a good two-wire IACV (test with ohmmeter), proper harness wiring, and manual EX ECU.

The manifold should seal OK if all the parts you have (head, intake gasket, manifold) are the late model type with the extra air injection ports at fuel injectors.

 

A leaking FIA system would be my first guess too.

 

Thanks for the help so far guys. Forgot to add, I am running a manual ECU. I will check the IACV today and make sure that is working. Correct me if I am wrong, but if the FIA system is leaking all the time, wouldn't that make the IACV open all the time as well? If it is a normally closed circuit. I did some looking around and found that a lot of guys are just tapping and threading these holes and plugging them with set screws and loctite.

 

IACV and FIA are completely independent functions.

 

Their functions are different during normal operation, but the FIA vacuum leak directly affects the IACV function. Anyway, 12v at the IAC leads. P0505 doesn't necessarily mean an open anyway, it just means that it is malfunctioning or operating out of parameter. Not likely that changing cylinder heads broke my IACV anyway. I'm going to plug the FIA holes. Thanks guys.

 

The effect is completely indirect and only occurs when the engine is cold.

 

Performed the FIA delete today by tapping and threading the ports and blocking them off with set screws. It went without a hitch. Engine runs great and my IACV functions perfectly.