Surging idle after y8 manifold swap on 96 DX....pls help me diagnose....
 

Ok, I've just finished my y7 to y8 intake manifold swap, and of course, now have a surging idle...surges from about 900 to 2000 rpm...here's the info:

Car: 1996 Civic DX
y8 manifold: 1997 automatic manifold w/ TB (so no messing with IACV wires!)

As far as I can tell, everything is hooked up correctly...

PCV valve to 1st large vacuum source on manifold
EVAP solenoid to 2nd large vacuum source on manifold
FPR to small vacuum source
and the vacuum nipple on the rear has been plugged

I just re-did all the gaskets, thinking that might have been the problem, but after changing gaskets, same exact problem.

Am I mising something?? Please help..

Thanks https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

1. check to make sure NO cracks in vaccum lines
2. make sure all plugs are plugged into the CORRECT plugs
3. whats it idling at? try adjusting the skrew on the throttle body, it could be idling too high
4. check and recheck that you have all vaccum lines hooked to the correct places

thats all i can think of for right now

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

search surging idle i forget what iti s called but you gotta clean it out i had the same prob

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

Is your car Auto or Manual?

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (Civic4less)
 

Thanks for the replies!!

Im sure the vacuum line are good....replaced all hoses w/ new ones
All plugs are correct....
The car is idling at 1500 - 2300 when cold, then 900 - 1500 when warm

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civic4less &raquo;</TD></TR><TR><TD CLASS="quote">Is your car Auto or Manual?</TD></TR></TABLE>

My car is a manual....

Im going to go try using my IACV, the one on the TB that came with the manifold looks like its seen better days...maybe that the problem

Please keep with suggestions just in case.... https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by awdriscol4 &raquo;</TD></TR><TR><TD CLASS="quote">
Im going to go try using my IACV, the one on the TB that came with the manifold looks like its seen better days...
</TD></TR></TABLE>

Does that make sense? And you shouldn't have an IACV on an automatic y8 intake manifold. Are you sure your gaskets are on the right way, I know my TB gasket was upside down, but since the holes still fit I never noticed https://honda-tech.com/forums/images...s/emsmilep.gif

but I suck like that.

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (Maness)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Maness &raquo;</TD></TR><TR><TD CLASS="quote">Does that make sense? And you shouldn't have an IACV on an automatic y8 intake manifold. Are you sure your gaskets are on the right way, I know my TB gasket was upside down, but since the holes still fit I never noticed https://honda-tech.com/forums/images...s/emsmilep.gif

but I suck like that. </TD></TR></TABLE>

I dont, the IACV is on the throttle body....so I just swapped throttle bodies since I knew my DX one was in perfect working order (I just had to swap the throttle rotors and springs, other than that, the TBs are identical) - Unfortunately that didn't work, same problem....

Ill check the gasket, you know....Im not positive its on correct...lol....

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

the rotor/springs look the same to me, why do people switch them?

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

UPDATE: Problem sovled

Well, the TB gasket was on corect, unfortuantely it was the wrong TB gasket, it was a TB gasket for a manual EX...so it didn't seal the IACV chamber at all....Thanks guys at Inline Four!! lol So I just re-used my old TB gasket, and it seems to be fine...but I will be ordering a new one...but straight from Honda this time.....

My only problem now is that the car wants to idle at like 3 or 400 rpm....it never dies, it just idles very low and hesitates for a second when you give it gas....any idea about that?

Thanks everyone for the tips/suggestions/ideas....I seriously doubt I would have even checked the TB gasket again if it wasn't for Maness' idea.... https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (awdriscol4)
 

*tear*

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by awdriscol4 &raquo;</TD></TR><TR><TD CLASS="quote">
I seriously doubt I would have even checked the TB gasket again if it wasn't for Maness' idea.... https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif https://honda-tech.com/forums/images/smilies/emthup.gif </TD></TR></TABLE>

https://honda-tech.com/forums/images...s/emsmilep.gif

But for the low idle, maybe your idle screw is just set low? Or did you check that?

Re: Surging idle after y8 manifold swap on 96 DX....pls help me diagnose.... (Maness)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Maness &raquo;</TD></TR><TR><TD CLASS="quote">*tear*

https://honda-tech.com/forums/images...s/emsmilep.gif

But for the low idle, maybe your idle screw is just set low? Or did you check that?</TD></TR></TABLE>

lol.... https://honda-tech.com/forums/images...s/emsmilep.gif

Haven't bothered checking it yet...it was set fine when on the DX manifold though...oh well...Im too tired and its too hot to mess with it anymore today.....at least it runs!! lol