HCivicSi23

I have a friend that has a manual 1997 Civic LX. I believe it has the D16y7 that does not have Vtec. The car is all stock and a daily driver car for him. He wanted to replace the intake manifold gasket and clean it up etc. So I helped him out. The intake was sucessfully taken out with disconnecting all vaccum hoses that connected to it, fuel hose as well as the coolant hoses. I also dissconnected all the clips that kept the manifold on.
I cleaned up the old gasket with a razor blade and some gasket remover, then put the new one on. I then recconected everything and when I started the car it reved up to 5,000 rpm and idled there for about 3 seconds then it drops down to 1,000... but every time it hits 1,000 it surges up to 3,000 then back down to 1,000. It does not stop doing this after the car is started.

I then tried to drive the car and the idle seems normal when in gear but the car jerks when stepping on the accelerator. Im not sure what is causing this because I am not an expert on the D series motors... so if anyone knows what it could be or what I might have screwed up... please let me know!

Libertariat

Sounds like you got some vacuum hoses crosses, double check with a haynes/helms manual.

HCivicSi23

I checked them and I cannot originally remember how they were configured. I looked for a picture in tha haynes manual, as well as chiltons, and it turned up no good picutre on how the vaccum lines are connected. Any other ideas?

jz98ctr

i'd say either vac leak/cross somewhere or an IACV issue. if you were changing the manifold did you either drain the coolant or just let it be? double check your coolant levels first cuz sometimes that can screw with the IACV at times too.

97Ej6mike

Make sure you check all your coolant hoses too, this is what almost killed my Y7 motor, i was pouring coolant into it for a good 5 minutes till we realized what was happening. Y7 manifolds are truly a bitch. Sounds like a vaccum leak. Also check to make sure your MAP and TPS sensors are pluged back in correctly.

Libertariat

y8 manifold - 453,563

y7 manifold - 0

No overtime this game.

97Ej6mike

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ek forever guy &raquo;</TD></TR><TR><TD CLASS="quote">y8 manifold - 453,563

y7 manifold - 0

No overtime this game.</TD></TR></TABLE>

hahaaha
Downdraft manifold FTL

also make sure you bolted the manifold down tightly, if theres the slightest gap in the manifold/gasket/head, then it will certainly cause it to idle very terribly.

HCivicSi23

The coolants fine and I know thats not screwed up. I double checked the vaccumm hoses and I dont think there crossed. If any one can throw up a picture of the vaccum hose configuration on a D series intake manifold... that would be great because any picture in haynes manual is terrible.

If anything, it could be the IACV which was slightly messed up. I had to take the throttle body off to get at some bolts on the intake manifold... so maybe I messed something up there?

jz98ctr

i also hoped that you had torqued the IM down properly...there's a certain sequence to putting it back on and torquing down the bolts....if i'm not mistaken you start in the middle and work your way towards either end of the IM flange...alternating as you go outwards.

HCivicSi23

Of course. I started with the one middle bolt and did work outwords. It allows for an even tightining for the new gasket, as well as alows for an even seal. I think the problem lays with the throttle body.

Laserjock

Sounds like a vacuum leak. I had the same idle surge when i replaced my Y7 to Z6 intake mani. I had a small piece of gasket stuck between the mani and tb

http://vfaq.com/mods/ICtester.html okok so you're not turbo.