HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge!
 

Alright, I've done quite a bit of searching on "idle surge", only to come up with mosly topics that talk about the fast idle valve on the OBD 0 or 1 vehicles. So I am making my own topic here as I have yet to find any that talk specifically about the issues I've run into with this. I am going to be VERY specific about my setup in order to cut down on possible future questions. Please bare with me!

I have a 1999 Civic Hatchback DX with the D16Y7 motor. I purchased a D16Y8 intake manifold. This particular manifold came off of an AT (Automatic Transmission) model. How do I know this? It does NOT have ports on the rear of the manifold for the 2-wire IACV (Idle Air Control Valve). According to the Honda parts catalog, the MT (Manual Transmissions) were the only models to use the 2-wire IACV. That means on the D16Y8 + AT configuration in a Civic EX, it uses a 3-wire IACV mounted on the bottom of the T/B (Throttle body); just like the D16Y7 is setup (Automatic OR Manual transmission).

I was NOT given a D16Y8 T/B, so I am re-using the D16Y7 T/B with a replaced throttle sping from a 1G B-series T/B that I purchased from a buddy. If unaware of the need to replace the spring, it's due to the configuration of the throttle cable in relation to the intake manifold. It's a neccesary modification.

Onto the actual swap... I swapped all existing components over into the new configuration (Modified D16Y7 T/B, Original TPS, MAP and IACV, purge solenoid valve, fuel injectors, fuel rail). I DID replace the original intake manifold gasket with a new D16Y7 gasket (it's cheaper than a D16Y8). I do realize there is a difference in the two, I visually compared them side by side and see no reason I would need to use a D16Y8; if I am wrong, PLEASE CORRECT ME. I DID NOT replace the T/B gasket as it was in good shape with no tears or holes. Again, I see no reason why I would need to use a different T/B gasket; if so, PLEASE CORRECT ME.

I have the intake manifold physically installed using ALL BUT ONE nut (directly center on the bottom row), as it's rather ackward to get to. I cannot see how this would cause a leak on it's own; if I am wrong, PLEASE CORRECT ME. In regards to the TPS and MAP sensor, I DO NOT have these connections reversed as I've checked the proper wiring to be certain they are correct. I've triple checked all possible open vacuum ports on the intake manifold as an open port COULD cause the idle to surge. There are two unused ports that I have covered well with duct tape for the time being (directly center where manifold mates with head, points up... as well a tiny port in the rear used for cruise control).

On the D16Y7 OEM configuration there are two coolant lines coming from the IACV (mounted on the T/B) and three vacuum lines coming from the intake manifold.

Coolant:
1. Water tube (runs to water pump from thermostat housing)
2. Small port on the right side of the intake manifold where medium sized coolant line attaches.

Vacuum:
1. Fuel Pressure regulator
2. PCV connection
3. Purge control solenoid

I transferred these over to the D16Y8 intake manifold just as they're supposed to be according to the best of my knowledge and from the best I can make out in the Honda parts catalog. I have since looped the two coolant ports on the IACV (still mounted to the T/B), and ran a single line from the water pipe over to the small port on the right side of the intake manifold where the medium sized coolant line attaches. Either way, it makes no change in my situation.

As the situation sits right now, with everything connected and attached, new coolant in the system with the air bleed from the lines (to the best of my knowledge), when I start the car, immediately it revs itself upto 6200-6300 RPM (according to my Rev/Speed Meter) for aprox. 5 seconds, then drops down to aprox 1500 RPM and proceeds to surge between 1500 -and- 3000 RPM within aprox a 5 second window.

Also to note, while driving the vehicle under this condition (while VERY annoying), I have noticed that when I apply the gas, the car will kick forward as if I stompped on the pedal and somewhat pulls on it's own for 1-2 seconds. I've noticed during deacceleration as this happens, and I apply the brakes to slow down, it's as if I have no power for the brakes (as if the car was turned off).

Honestly here, WHAT GIVES? What am I overlooking? Is the IACV twerked? Will it need to be replaced? Is this swap a waste of time? https://honda-tech.com/forums/images...es/emsmile.gif I've put up with this for a week and I'm actually going outside to reverse the process for the time being. I simply cannot take this any longer.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

Anyone out there?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

Seeing that it revs up as high as it does, it almost sounds like a huge vacuum leak.

So was the Y8 manifold from a 99-00 civic with air-injection?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Marauder)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder &raquo;</TD></TR><TR><TD CLASS="quote">So was the Y8 manifold from a 99-00 civic with air-injection?
</TD></TR></TABLE>

Very important piece of information here, that is about the only vacuum leak that will cause that much of an idle surge

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (civic-4-ges)
 

I'll take "Symptoms of a Vacuum Leak" for $100, Alex. https://honda-tech.com/forums/images...s/emsmilep.gif

Cover the hole infront of the throttle plate leading to the IACV - what happens?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Marauder)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder &raquo;</TD></TR><TR><TD CLASS="quote">Seeing that it revs up as high as it does, it almost sounds like a huge vacuum leak.

So was the Y8 manifold from a 99-00 civic with air-injection?

</TD></TR></TABLE>

That's my guess. The only way I could get the damn 99-00 air injection mani to work on my 97 y7 was to JBWeld the ports closed.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Marauder)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder &raquo;</TD></TR><TR><TD CLASS="quote">Seeing that it revs up as high as it does, it almost sounds like a huge vacuum leak.

So was the Y8 manifold from a 99-00 civic with air-injection?

</TD></TR></TABLE>

Hmm, that's new terminology to me. How can I tell? What is the difference?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (EE_Chris)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">I'll take "Symptoms of a Vacuum Leak" for $100, Alex. https://honda-tech.com/forums/images...s/emsmilep.gif

Cover the hole infront of the throttle plate leading to the IACV - what happens?</TD></TR></TABLE>

The hole on the inside of the throttlebody? I will check a bit later.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

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

Hmm, that's new terminology to me. How can I tell? What is the difference?</TD></TR></TABLE>

did you notice any grooves on the face of the manifold?

also, why is it necessary to swap the spring on the tb?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

I got a lot of my information from the following site. It's no longer "up", but I was able to retreive the data and most photos via http://archive.org.

http://web.archive.org/web/200...iswap/

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Smith Wise)
 

https://honda-tech.com/zerothread?id=717086

if it looks like mine, it's 99-00 y8 IM

WE should have used a 96-98 on our 99-00 d16y7 b/c our engines don't have air injection

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Smith Wise)
 

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

did you notice any grooves on the face of the manifold?

also, why is it necessary to swap the spring on the tb?</TD></TR></TABLE>

When you say 'the face', are you referring to where the manifold meets the head?

In regards to the spring and plate. The throttle cable will not work properly with the Y7 configuration once you've relocated the T/B to the side-draft configuration on the Y8 manifold.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RareSI &raquo;</TD></TR><TR><TD CLASS="quote">
Hmm, that's new terminology to me. How can I tell? What is the difference?</TD></TR></TABLE>

Here is a pic of a manifold that I pugged up the air-injection. If you plug the four holes where I have shown, you don't have to worry about the nipple on the flange or the other hole that I left open.

http://www.we-todd-did-racing.com/we...MXk1NDE%3D.jpg

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

The spring on the TB needs to be replaced because it just does..... https://honda-tech.com/forums/images...s/emsmilep.gif Sorry my crazy sense of humor explodes on this forum like a mofo. Well the spring from a Y8 TB faces the opposite direction in think....all i know is that you have to change that and the TB plate because the Y7 TB vertical plate will not work. Iv'e done this swap before so if you need any questions just ask, but im at work right now. later

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (EE_Chris)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">I'll take "Symptoms of a Vacuum Leak" for $100, Alex. https://honda-tech.com/forums/images...s/emsmilep.gif

Cover the hole infront of the throttle plate leading to the IACV - what happens?</TD></TR></TABLE>

I just went out to check into that. When I cover that oddly shaped hole with my fingers completely, the surge goes away.

What does this tell me?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Marauder)
 

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

Here is a pic of a manifold that I pugged up the air-injection. If you plug the four holes where I have shown, you don't have to worry about the nipple on the flange or the other hole that I left open.
</TD></TR></TABLE>

Interesting. After looking at your photo, I notice the port that points upward in the center where the manifold meets the head. I have this on mine, I've mentioned this in my first post. However, I've never noticed those ports on the face.

After going through this topic and two new topics I discovered, I am still slightly confused on my next plan of attack.

Facts:

- I have a 1999 D16Y7 motor
- I am attempting to use a 1999-2000 D16Y8 manifold (apparently with the air injection configuration).

Questions:

- Do you plug the air injection ports when installing a 1999-2000 D16Y8 manifold on a 1996-1998 D16Y7 engine ONLY or both 1996-1998 AND 1999-2000 ?
- What intake manifold gasket is to be used? 1996-1998 D16Y7 engine as well as 1999-2000 D16Y7 engine?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RareSI &raquo;</TD></TR><TR><TD CLASS="quote">What does this tell me?</TD></TR></TABLE>

That you have a vacuum leak. What does the idle calm down to when plugging this hole?

And yes, you should seal the air injection holes on the 99-00 Y8 manifold when using it on ANY Y7.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (EE_Chris)
 

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

That you have a vacuum leak. What does the idle calm down to when plugging this hole?

And yes, you should seal the air injection holes on the 99-00 Y8 manifold when using it on ANY Y7.</TD></TR></TABLE>

I didn't look at my RPMs, but it sounded to be about 800-850.

Use the Y8 gasket as well I take it?

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

I'm sure the y7 and y8 intake manifold gaskets are the same. THe throttle body gaskets however are different. Use the throttle body's gasket. So since you are using a y7 tb, use the y7 tb gasket. I will be doing a similar swap in a few weeks, but on my 99-00 y7 motor with a 99-00 y8 intake manifold and head. If I get the same problems I'll let you know, but like everyone else said I'm sure it's a vacuum leak. Good luck sir https://honda-tech.com/forums/images/smilies/emthup.gif

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (chowmien)
 

dude FUCK yeah not having a nut on will let it leak man.

shit vacuum leaks are pesky,
do everything you can to avoid them.

get that nut on there.

get it on there from the underneath with your fingers(yeah its hard i know but its possible!)

then tighten it from the top with a standard 12mm box wrench.

if it still surges hunt down the vacuum leak(it most likely is a vacuum leak).
one recommended method would be to spray carb cleaner on suspect area,
if theres a vacuum leak, it'll suck the carb cleaner into the engine and your idle will rev up! so find the leak that way.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RareSI &raquo;</TD></TR><TR><TD CLASS="quote">Use the Y8 gasket as well I take it?</TD></TR></TABLE>

Looking at a few catalog pics, they appear to be the same gasket with respect to the air injection holes. So it appears it would not matter which gasket you use because each is going to expose the air injection holes to the intake manifold - which means you gotta seal up the AI holes either way you slice it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RareSI &raquo;</TD></TR><TR><TD CLASS="quote">I didn't look at my RPMs, but it sounded to be about 800-850.</TD></TR></TABLE>

Stock rpm idle is like 750 +/- 50 rpm and this is with the IACV doing its thing to control the idle which means you gotta vacuum leak.

The severity of the surge (how high it goes) will really clue you in on how big of a vacuum leak you're looking at. Seeing as how you go as high as 3k and you don't have the AI holes filled (and who knows about the nut you didn't use to secure the manifold - it could also cause problems), I'd say you found your problem.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (chowmien)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chowmien &raquo;</TD></TR><TR><TD CLASS="quote">I'm sure the y7 and y8 intake manifold gaskets are the same. </TD></TR></TABLE>

Not so much. I work at Honda in the parts department.

1996-1998 D16Y7 + D16Y8 / 1999-2000 D16Y7 -- Part Number: 17105-P2F-A02
1999-2000 D16Y8 -- Part Number: 17105-P2P-A01

I've visually looked them both over, and don't see much of a difference, but there is.

I'm willing to get a photo of them side by side if you like.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (RareSI)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RareSI &raquo;</TD></TR><TR><TD CLASS="quote">
1996-1998 D16Y7 + D16Y8 / 1999-2000 D16Y7 -- Part Number: 17105-P2F-A02
1999-2000 D16Y8 -- Part Number: 17105-P2P-A01</TD></TR></TABLE>

The 99-00 Y8 gasket is a special one for air-injection. It has a sheetmetal core with different gasket material on both sides.

You need to pull the Y8 manifold off and use JB weld or silicone to seal up the air-injection holes and reinstall with all the hardware.

You will still get a vacuum leak even using the Y8 castings, cause the cylinder head you have wont seal the air-injection.

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (Marauder)
 

On the link you gave.http://web.archive.org/web/200...iswap/.They had the same problem andsaid that the intake was not tightened up enough. I would make sure and get that screw on there. You would be surprised what one screw could do. https://honda-tech.com/forums/images/smilies/emthup.gif

Re: HELP: D16Y7 -to- D16Y8 intake manifold swap >> Idle Surge! (badream20)
 

I thought about swapping my intake mani y7 for the y8. Is there alot of diff? i heard it would give you better high rpm power or torque?