D16Y8 Vacuum and Coolant Routing

rekvijem

New Member
I have gotten my hands on a Canadian 99 Civic Si (D16Y8) that was previously ripped apart and finally have the time to get it back together, but have a few questions about the cylinder head and intake manifold hose routing. The guy who had it originally also swapped the trans to manual.

Following are pictures of the inlets and outlets to hook up. I should also mention that the car is equipped with the worst looking "cold air intake" I have ever seen in place of the stock airbox, so I have included a picture of those connections and a piece that was previously hanging off of it.

An interesting thing, going through the service manual there are a bunch of discrepancies. For example, page 11-249 shows an exploded view of the throttle bodies, in which my throttle body looks just like the B16A2 shown, and the D16Y8 tb shown seems to be from an Auto D16Y8? Furthermore on 9-4 when showing the intake manifold the throttle body does look exactly like mine (also showing the manual trans IAC valve) and on the port side of the manifold there is a small vacuum connection that isn't shown in any other diagrams that I can find (the one in my accompanying pictures that I don't know what it connects to), but in the vacuum connection diagram that I attached to this post, there is no mention of that connection.

If anyone is able to confirm or deny my guesses or even take a picture of some routing in their car that would be amazing. Thanks!

Here are two of the photos that wouldn't fit because of the limit:

Weird piece:


In the car:
 

Attachments

Krukowskid

New Member
I would tell you everething with better photos, but:
1. From valve cover to intake
2. Red - Yes, Orange to red form 4th Photo
3. Red - Yes
4. red to Orange form 2nd Photo
5. Green + Orange FITV heating, Orange + purple throttle heating (not necessary)
6. Braking servo
7. To blue from 12 photo
8. Cruise control
9. To fuel tank
10
11. To thing from 1st photo
12. Red form 7th Photo
 


Last edited:

rekvijem

New Member
I would tell you everething with better photos, but:
1. From valve cover to intake
2. Red - Yes, Orange to red form 4th Photo
3. Red - Yes
4. red to Orange form 2nd Photo
5. Green + Orange FITV heating, Orange + purple throttle heating (not necessary)
6. Braking servo
7. To blue from 12 photo
8. Cruise control
9.
10
11.
12. Red form 7th Photo
Thanks millions for the quick reply! There are just a couple more connections I need to know now, and a couple clarifications.

First, am I correct to assume the following:

Attached Photo 1:
- Blue hose in foreground, circled in pink, goes to female outlet on CAI circled in orange (See photo 11 in OP, just to the left of red circle)
- Purple circled female hose goes to dark blue/purple in picture 1 in OP
- Green, see coolant routing below
- What connects to red?
- What connects to grey?

Attached Photo 2:
- Orange goes to OP Photo 9's red (notice grommet on orange hose, and holder for grommet in photo 9)?

Attached Photo 3:
- Red hose going to filtech box, where does this connect?

Attached Photo 4:
- Is purple the brake servo connection you were talking about that connects to OP Photo 6 red?


Coolant routing through throttle body and IAC:
- Begins at OP Photo 4 blue, connecting to the lowermost light blue connection in OP Photo 1
- OP Photo 1 orange goes to OP Photo 5 purple
- OP Photo 5 oranges connect
- OP Photo 5 green goes to the first photo attached to this post's green to complete the circuit.

So essentially coolant starting at the side of the cylinder head, running through the throttle body, through the iac, and exiting near the lower rad hose.

Thanks again for the help!
 

Attachments

Krukowskid

New Member
2nd is going to fuel output
4th Yes, this is servo vaccum line

I am not sure about 1st, and 3rd, but 3rd is prob. On your diagram (evap)

Thin vaccum line on servo is prob. To Cruise control
 




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