Recently Mid Atlantic motorsports installed a 99-00 Y8 manifold on my 98 civic Dx. They did a great job by the way, thanks Brian and Ray. Well we have seemed to run into a problem that makes no sence. After driving the car for 10-15 min we get a check engine light. Reading IAC Malfunction. Problem is it not melfunctioning, its working perfect. What could be causing this problem? and yes we are running a y7 throttle body with all y7 sensors and y7 fuel rain and injectors. Also light only comes on while driving. Should i just switch to an OBD1 ECU, will that get rid of the problem?

 

Help

 

check for leaks, was it working before you swap the intake manifold? you said that is not malfunction? how do you know? did you test out the sensor? you can swap out the obd1 ecu with obd2 to odb1 harness, and the obd1 ecu still looking for the iac sensor. take it back to the shop and let those guys look it over again.

 

The exact same thing happened to me when I put the Skunk2 manifold on my 99 Si. We checked EVERYTHING. Even cleaned everything, swaped IAC's, vacuum lines and could not figure it out. The car ran GREAT. Put the Kenji P28 in and the problem went away. I dunno.

 

The shop and myself have looked at everything several times. They said the IAC is working like it should be, checked for leaks and didnt find any. They said the OD2 ecu is more sensative. They said going to OBD1 will be better. They said they couldnt figure it out, they said everything is working great. Becides the fact the idle is a ittle high. I am at like 1100 went i first start then goes to 900. But when im driving in gear and come to stop and put the car in nutral it goes 1100 but then relaxes to 900. Why does the car jurk though when the check engine light comes on?

 

Bump

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by speedehatch &raquo;</TD></TR><TR><TD CLASS="quote"> Becides the fact the idle is a ittle high. </TD></TR></TABLE>
That's probably why it's coding. 14 right? If the ECU sees an idle speed out of spec it stores that code. Find out why it's idling high and it should be good.

 

http://community.webshots.com/user/hondaae83
Go to last album: Manifold problem for pics of the install, does everything look right?

 

Have you checked for vacuum leaks? Is the throtle plate closed all the way?

 

I think so ill have to check tommarow. The throtle is a little stiffer, when i had the y7 the throtle plate was easy to push in the engine bay and now its harder with the y8 plate. Its worth the look. Ill let ya you know what i find, Any other thought guys?

 

Everything looks normal. What about that little hole all the way at the very bottom left on the back of the manifold? Is anything suppose to be there?

So is switching to OBD1 going to make the problem go away with the check engine?

 

You said you're using a Y7 tbody....where does the Y8 'plate' come into play here? Did you switch something around here?

Also, there should be NO holes/ports of any kind exposed to free air on the manifold. If you have one, as you indicate, plug it up....does it change your idle?

 

I located a nipple on the extreme left bottom on the back of the manifold where air was leaking. I put my finger to seal it, and it made my motor almost stall. VACUUM LEAK!!!!. What does this go to, i plugged it up and i hope that fixes my problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by speedehatch &raquo;</TD></TR><TR><TD CLASS="quote">I located a nipple on the extreme left bottom on the back of </TD></TR></TABLE>


Cruise Control vacuum source

 

does that just get pluged?

 

If you don't have cruise control, then no problem plugging it up

 

You think it might be that your using an auto manni? Just a thought! Hope you fiqure it out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic-4-ges &raquo;</TD></TR><TR><TD CLASS="quote">If you don't have cruise control, then no problem plugging it up</TD></TR></TABLE>

Correct. Just cap it.

 

if you are using the auto mani thats good, but no one is taking into account the 99 manifold has AIR INJECTION, i hope you at least jbwelded those air injection holes shut

 

Your right. I think that might be his problem. If its an auto manifold, he has to JB weld those holes shut.

 

no no no, the auto manifodl is correct on a y7 swap, if its a 99 up and he has a 96-98 head he will have a vacuum leak due to air injection on the intake manifold flange