i have a 99 civic ex 1.6 vtec auto i just got as a project.here is the deal. at some point the previous owner had the head and manifold changed out due to bent valves.i looked at motor it says y8. and car itself has air injection system but not manifold and the hose that goes to intake manifold has a bolt in it. and there is no nipple like on the y8 manifold for the hose to go.the car starts idles at 2200 then once it gets warm the idle surges.i hear alot of air but see no leak.i sprayed tb cleaner front back side all over no change im gasket is new also.can i get a y8 manifold with the air injection holes and put it on to fix this issue or is the head different too. does a y8 head have air holes like the manifold? not sure what head is on the car it is 1.6 vtec.

 

96-98 Heads and Manifolds DO NOT have the air injection system

99-00 Heads and Manifolds DO have the air injection system.


If your head is a 99-00, and has the air injection system, it is best to get a 99-00 y8 IM to match.


If it was revered, and your IM was 99-00 and Head was 96-98, you could just have the 99-00 IM air injection holds welded shut, but obviously this is not the case here. The problem is you cannot weld the holes on the 96-98 head, due to them being large enough to accomodate both the air being injected as well as the fuel being pumped in

Hope this helps

 

There must be a leak or extra hole somewhere. The engine can't run without air. It should stall if you cover up all the idle bypass holes in the sides of the throttle body before the plate. If one of those holes is drawing excessive air, the valve associated with it may be stuck open. Also on some models there was a cold fast idle valve on the thermostat with air hoses leading to it. It is very easy to snap off the top of that valve and create an air leak.

 

Learn something new everyday, any pics of the difference? lol Id like to see

 

im guessing this is a 96-98 head and manifold on my 99 block,99 ecm.what do i need to do for the car to run correct if thats the case.

 

I think you are correct, sort of. He's assuming the leak is in the AIr Injection System, not the actual Air Intake system. (I may have misunderstood your post, and if I did, my apologies) But, the air leak has to be somewhere other than the Air Injection System, because....


If the head and IM match, than the air injection system is not the cause of your problem. The block has NOTHING to do with this. It's when you mix the head & IM that you run into the issue..

96-98 head + 99-00 IM = FAIL (Unless you weld shut the holes on the IM)
99-00 head + 96-98 IM = FAIL

96-98 head + 96-98 IM = WIN
99-00 head + 99-00 IM = WINSAUCE!

As for a pic... Here is a shot of the holes on the 99-00 IM's



Head