So I swapped intake manifold on 97 accord to f23. Started it up and immediately surging idle. 1k to 3k. Sprayed brake cleaner in areas but only changed when I sprayed near fuel injectors so my question is did I not set injectors well enough? Or because I forgot to silicone the f23 control ports on lower intake? I didn't find any other vacuum leaks. Please let me know. Thank you! Can the ports be siliconed while installed or is it full uninstall?

 

Some of the F23 intake manifolds have what is called a fuel injector air control system. You will see a port on the top of the intake manifold flange. it runs along the top of the intake to each injector. This port allows controlled air into the injector bung to help atomize the fuel better. If you do not have the solenoid hooked up, or plug these holes they will cause a vacuum leak.

Here are some pics of my FIA intake manifold;
If your using a B2 gasket it leaves the FIA ports into the injectors wide open like this picture.




The only way to block the 4 FIA ports is to remove the intake manifold and fill the ports with silicon gasket maker or JB weld. Just make sure that you don't use to much and go into the injector port. Or you can remove the injectors and fill them from that direction. Save you from having to remove the manifold.

 

So I blocked those off and it idled fine for a bit but now it's back idling from 1k to 2k. Doesn't do it in drive or gears just park and neutral. I can't see any vacuum leaks. So I'm kinda stumped. Any idea on how the vacuum lines need to go? Currently I have fia nipple plugged lower intake vacuum nipple plugged. First nipple for cruise second egr third is fuel regulator. Then brake boost in top pcv on side nipple. Wrong?

 

Have you tried plugging the FIA ports going into the injectors?

 

Yes I did. With jb weld. Just took it on a drive. It surges while driving to. Not so much tho. Is it possible that my iacv is the issue? I'm at a loss

 

Could I possibly have clogged iacv with silicone? I am so frustrated

 

If the IAC was clogged it would bogg at idle not surge. If the IAC is stuck open it could cause this. Surging is usually caused by unmetered air entering the intake track. AkA a vacuum leak.

Check all your gasket surfaces and vacuum hoses for vacuum leaks.

Did you make sure that the gasket mating surfaces were clean and free of any uneven surfaces? did you use new gaskets?

An air bubble in the coolant, a disconnected or malfunctioning ECT sensor can also cause idle surge and erratic engine operation.

 

New gaskets yes and new vacuum hose on all. Mating surfaces were clean. How do I know if Iac is stuck open? Ect? How do I fix air bubble? If I have one?

 

if the IAC is working and you unplug it. It will close and the idle RPM range should drop.

Check the wire and connector on the ECT sensor and make sure they are clean and tight. There is a resistance test you can do on the sensor to test it if you have access to an Ohmmeter.

Air bubbles in the cooling system are removed by bleeding the system via the rad cap or by using the air bleed valve on the thermostat housing.