i just swapped my y7 manifold for a y8 manifold today. now, when it idles(if thats what u wanna call it) it fluctuates pretty badly up and down. i plugged the very small nipple(vacuum) on the back of the IM, toward the bottom. the only thing i can think of is the there is nothing plugged into the IACV on the manifold, but the y7 throttle body has a built-in IACV doesnt it? also, the car runs fine while driving, only the idle is strange and its slightly jerky going from none to partial-throttle. any help would be very appreciated.


edit: yes, i searched under everything manifold related tghat i could think of.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WangChung &raquo;</TD></TR><TR><TD CLASS="quote">i just swapped my y7 manifold for a y8 manifold today. now, when it idles(if thats what u wanna call it) it fluctuates pretty badly up and down. i plugged the very small nipple(vacuum) on the back of the IM, toward the bottom. the only thing i can think of is the there is nothing plugged into the IACV on the manifold, but the y7 throttle body has a built-in IACV doesnt it? also, the car runs fine while driving, only the idle is strange and its slightly jerky going from none to partial-throttle. any help would be very appreciated.
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There you go. You need to get that plugged up. Huge vacuum leak.

 

no, the sensor is there, but there isnt an electronic plug plugged into it. the unit is there, there are lines going into and out-of it, but its inactive.

 

It's your IACV fo sho'. Which throttle body did you use?

 

If you used your y7 tb then the iacv is on the bottom of the tb and is the one you should be using. The one on the back of the intake manifold needs to be taken off and covered up. I'm not sure if just plugging up the iacv holes will do the trick. Also are you using a 96-98 manifold or 99-00 manifold?

 

ok.....what you are saying is that you have a manual y8 IM (which has the iacv on the back of the maifold).....and u are using the the y7 TB (which has a 3 wire iacv on it)....

is the manual iacv so on the IM? you may want to take it off the IM, get some sheet metal....drill holes to match the y8 iacv, put some rtv on it....and just block it off.....

did u check all the nipples? is everything pluged up? Did u use new gaskets? (IM and TB).....did u clean off the old gasket well?

did u get the 96-98 IM or the 99-00 IM.....99+ u need to block off the air injection holes

 

yo I did that same swap today and when I first started it up, it started idling at 5000 rpms and blew some white smoke out of the exhaust. I turned it off right away cuz I knew something was very wrong.

Somebody please call me a noob and tell me what I did wrong.

Sorry for the question on your thread but I need to find an answer for this one cuz i suck.

 

sounds like you got a coolant and vacuum line mixed up and are burning coolant. also, if i block off the iacv port, what should i do with the two lines going into it?

 

k, ive heard of people blocking off the iacv coolant nipples completely, but i have lines running through them. i need to double check my lines tomorrow a.m.

 

I just pinched off the two lines coming out of the iacv.... If you ever plan on going to obdI make sure you keep the two wire iacv off of the y8 manifold... Make sure you used the correct tb gasket as well...

 

i used the y7 tb gasket, cuz i used the y7 tb. there isnt any leak with the nipples just pinched?

 

What exactly is the air injection holes??

And what are the differences between the 96-98 MT/AT and 99-00 MT/AT??

 

ok.....

the only coolent hoses should be comming off of your y7 iacv......(on your tb)

????? maybe i misunderstand ya.....you should't have any hoses on the y8 iacv connected.....or maybe i read something wrong.....just remove the 2 wire y8 iacv (the one on the im) and block off the holes thats left...

run your y7 tb w/ the 3 wire iacv....just the way it was ran stock....you may have to extand a few wires/coolent hoses that goes in to your y7 tb

im me.....if u have anyquestions...if u want

 

bump

 

k, today i double checked my hoses and the surge is still there. the only other thing i can think of is to check the iacv and clean it. but thats gunna hafta wait, cuz ill have to drain the whole coolant system. when the iacv is dirty, it wont throw a code, right? cuz i have no cel's. another thing it could be is a vacuum leak, but who knows.

 

I don't think it would matter if the iacv is dirty, as long as it isn't totally blocked you know?

As for my problem, i realized that i was a dumb *** and didn't seat the intake manifold properly and there was a huge vacuum leak sucking in air and coolant along with it.

Does anyone know the right tightening sequence for the nuts on the intake manifold?

 

well, i solved the problem! it turns out that while i had my TB off, to clean my iacv, i realized the y8 gasket wasnt sealing all of the ports on the inside of the throttle body. DUH! i was using the wrong TB gasket! well, it runs great now and idles perfectly. thanks for your guys' input.