Having trouble with intake air hose routing...

[Megadysart]

Hey guys, I've been rebuilding my van for some time now, and I've been dealing with this particular assembly of hoses and vacuum lines and coolant(?) lines for the entire time. I've been skipping around it and doing everything ELSE to rebuild the rest of the van, and it's going well, but now I'm finally left with just this predicament to deal with. It has to do with the little tee thing that connects to the bottom of the air hose. It has a large connection that looks like it connects up to one part of the weird little X shaped coolant/air/vacuum hose mess of an assembly, and then it has another leg that looks like it is connected correctly that goes towards the power steering pump area. Here are the pictures that I have of these various hoses and fittings.



Sorry if these pictures appear blurry, I had to use the flash on my phone and sometimes it's less than impressive....any way, if anybody has a diagram of the way that these things fit with each other, or how they are mounted, or even a diagram or picture containing that X shaped component in it's mounting spot, I could mount it where it goes and then connect the dots and try to see if any of the hoses line up with what they're supposed to connect to........if that makes sense? At this point, even if somebody drew a MS Paint drawing of how these are connected to the engine, it would be better than me trying to not go insane by trying to figure out how these connect!

PS, I have a suspicion that the EGR has something to do with this? It looks like the hose fitting jutting out of it MIIIGHT be part of this..just a thought.

[timsrv]

Sorry to be the bearer of bad news, but that pipe in your 1st few pics is for the air valve & the upper half of the intake manifold will need to be removed in order to put it on. Here's a picture of how it is mounted:



The 2nd (picture 7) goes into the small hole on the underside of your rubber throttle body hose (the one with the patriotic tape on it) and is also for the air valve. Tim

[ninz30]

+1 ^


Tim what's your secret on removing the old paper gasket? Your upper intake looks great.

[timsrv]

Click here & scroll down to post #12. I use a die grinder with 2" Scotch Brite conditioning discs. Tim

[Megadysart]

Sorry to bump this kinda old thread, but what does the air valve do? Mine is broken, the plastic nipple where the bigger hose connects broke off, probably because it's pretty old and brittle and cracked when I was taking the hose off of it. In fact, there might be a hose in my garage with the plastic part still stuck inside it. How does this valve work, and is it crucial to the operation of the EFI system? I am looking to simplify the induction system and maybe get rid of things that I either A) Don't have money to replace or B) Don't really need. I've already gotten rid of the heater system in the front, since I live in AZ and it rarely gets cold enough to warrant the front heater (rear system is still functional incase of an overheat). Can I just bypass the air valve? I'm in the process of ordering an electronic vacuum pump that works at 25 H/g, so my next plan is to get rid of all the manifold vacuum routing and route all the VSVs and vacuum accessories to the electric pump. Just wondering if could give me any insight to how the intake system on these vans work, and what that particular valve actually does, so I can decide whether or not it's worth going down to NAPA and paying for a new OEM one. Thanks Tim!

[timsrv]

When the engine is cold it wants to idle low. The air valve opens/closes with engine heat & this keeps the engine idle at the correct RPM. If you're in a warm climate you could eliminate it along with the 8mm coolant bypass hoses. It might run a little rough when cold, but probably not too terrible. I don't know what benefit there would be to using a vacuum pump instead of manifold vacuum. Gas engines have a free supply of trouble-free manifold vacuum. Seems to me you'll be reducing reliability and adding complications by adding a pump. Tim

[ninz30]

I recently had a similar issue. I wasn't able to find replacement vac hoses for the ISCV circuit, so I installed the old ones and they created vac leaks. I then bypassed the ISCV and the van idles like crap. I also live in warm climate and it was around 95* in the shade that day. I decided to link a 5/8 hose from the T under the intake boot to the side of the intake manifold where the vac ends. I manually adjusted the amount of air the engine received and got it to idle properly. After warm up the van idles fine and I can completely cut off the air from the boot to the manifold with an idle drop of 50-75 rpms.

In short I do think you need the ISCV. If you completely eliminate it, starting will be a pain even in warm weather. You will have to press the throttle pedal down slightly in order for the tps sensor to help out and allow the needed air to rush in.