I was looking around in my engine bay this afternoon because I need to clean my EGR ports. I was just getting an idea of what needs to be removed when I noticed it appears I have several things missing.

Some background: Yes, I'm getting a CEL 80. I have a constant hiss coming from what appears to be the middle of the upper portion of the intake manifold. Vacuum leak? The hiss does not vary with RPM, and only goes away when the car is off. Upon turning off the car, the hiss slowly goes away (takes about 5 seconds) like a semi's airbrakes, just not as loudly or quickly. I think I'm going to completely remove the intake manifold when I clean the EGR ports. Maybe that will shed some light on it. If you have any ideas, please share them.










^^^^^ I know nothing is missing in this picture. I just want to know what this is for. ^^^^^



^^^^^ I don't think anything is missing here. Is this a vacuum purge? ^^^^^

 

3 is fine.
8 is like that on my head too.
17 is the flywheel inspection cover.
18 is the ATTS breather hose.

 

Thanks Vin,

3. What is it?

Any ideas on the others?

 

No idea, probably something that was used in jdm motors.

 

3. Looks like where the vacuum hose for the cruise control went.
4. Bracket for cruise control cable.
5. Bleeder bolt for cooling system.
10. Looks like bolt hole for factory intake box.

 

3. CC works perfectly as it is plugged in just 2 hoses down.
4. CC is on the other side of the car. Maybe this is for CC in RHD models?
5. Thanks.
10. That makes sense.

 

My bad, thought CC was removed because on the 4th gens that CC cable runs through that bottom hole.

 

Looks like you're going to have to clean your egr valve and ports per the cel. Spray some carb cleaner around the intake mani to see if you find the vacuum leak.

 

Yep, that's the plan.

Tried that with no luck. From the sound, it appears to be coming from the inside of the upper portion or from below the upper portion. I can't really see what's going on in either case.

 

Hmm, maybe one of the gaskets is leaking. Why are you removing the intake mani to clean the egr ports? It's not necessary and will be a huge pita in the SH.

 

The only reason I'm considering removing the IM is to find this hiss. It's been there ever since I replaced my clutch.

To get the tranny case back on, my buddy jacked up the motor about 6 inches. I'm thinking he might have pinched/smashed/cracked/disconnected something.

 

All of that looks pretty normal to me. 9 may be an empty slot having to do with an AT harness. How exactly would you describe the hiss? I think the sound you hear after shutting your car off is maybe just the excess air bleeding out of either the intake, manifold, or both. I have an SRI and hear that sound after shutting my car down too (basically like the motor is exhaling). I'll vouch that pulling the IM is a pain. After you've done it once, it's not as bad to do it again, but it does suck. And watch out for the knock sensor, I busted mine the first time down there. Are you sure the sound you're hearing isn't air moving around either the vac lines or coming through the IACV? Maybe PCV? If it isn't causing problems, I'd be hesitant to go digging. In fact, unless it's the main IM gasket at the head, you might as well just pull the plenum and butterflies and save yourself the headache of trying to get the runners off.

 

The hiss sounds exactly like letting air out of a car/bicycle tire via the valve stem. I doubt it's normal since it wasn't there until my clutch replacement. It's definitely not coming from the main IM gasket at the head. So I might not pull the entire manifold. I might just pull the fuel rail and injectors to do the EGR ports, then pull the butterflies and plenum to investigate the sound. But I am going to find out what's causing this.

Since you brought up the butterflies, I do have another question. I've read on here and other Lude forums about plugging the IAB solenoid vacuum line directly to the intake manifold, in order to get the butterflies to open earlier. The question is, where is this vacuum hose and where in the IM should it be plugged in? Just not my area of expertise. I'm more of a suspension/exhaust/car audio/lighting person.

 

#3 Is fine, its plugged from the factory.

re; #3
You need to remove the middle vac line (the one next to #3) and plug it. It's for the OEM intake vac box, which you no longer have.

 

Yeah, I know. Laziness is a bitch to overcome.

 

1. nothing. Remove it.
2. nothing. Remove it.
3. I've got the same thing after removing the intake baffle solenoid.
4. spare cable holder for automatics, not used in 5th gen Prelude
5. coolant bleeder nut on top of thermo housing.
6. bracket to hold wires with special zip-tie
7. plug in end of oil galley in head.
8. never used.
9. maybe the intake baffle solenoid that's no longer used?
10. nothing
11. nothing
12. nothing
13. nothing
14. nothing
15. nothing
16. nothing
17. ignition timing inspection window plug
18. ATTS unit breather?

 

18 looks like it could be the leak you describe. Where does the other end go?

 

18 is the breather for the ATTS unit

 

Just because it is a hole, it does not necessarily mean that something needs to fill it.

 

Hmm, 18 is interesting. I have a '97 and just went and checked and I don't have that clip or hose at all. I know they changed some of the emissions components after '97, but that is odd. Is there a hose number on there? And unless they added an ATTS breather after '97, it's not that.

 

It's in the 97 parts catalog, should be there in your car. Someone probably forgot it after a clutch change.

 

So our engine bays are full of fat chiks?

Well, thanks everyone for putting my mind at ease. Again, if you have any ideas on the hiss, let me know.