1G 2 quick Intake & exhaust questions

[XC92]

I'm reconnecting all the vacuum hoses on my '92 Talon TSi and one of the vacuum splitters appears to have a constricted port on one of the ports. It's the red purge valve splitter, with one hose going to the purge control solenoid valve on top of the firewall on the far driver's side, one going to the purge valve and one going to the "P" port on the throttle. The latter is the constricted port.

Here's a photo I took:

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The hose that goes to the throttle "P" port is connected to the throttled port on this splitter, designated by a white stripe.

I know that it's constricted because when I removed it and tried to blow air through it, it was much harder to do than with the other 2 ports.

Is this the way it's supposed to work? I see no mention of any constriction in the FSM or elsewhere, yet I'm pretty sure that this is how the car came stock.

The other question is, how do I get the lower exhaust manifold heat shield on? It's sort of like the timing belt cover that way, really, almost impossible, to get back on. Do I need to remove anything, like the oil level dipstick tube?

 

[XC92]

Might as well answer my own questions. I wasn't able to find anything on that constricted port so I just reconnected it the way it was before. Idle is still a bit rough but that's likely due to a bad O2 sensor that I just replaced.

Speaking of which, to answer the second question, with the O2 sensor out it's much easier to install the lower heat shield, and since I was replacing it that's what I did. Still want to know what the deal is with that constricted port though. Nowhere does it appear to be documented.

 

[petrosian]

Just curious, when you were testing that splitter by blowing into it, did you try sucking air through it also? Since the throttle body (for turbo models) sees both vacuum and pressure…. I.e. check valve behavior...

Another thought, if it is just an ordinary splitter, be it constricted, wouldn’t the other two ports ultimately see the same vacuum/pressure, just maybe slightly delayed? Just pondering…

That piece isn’t specified by number in the parts catalog either, though.

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[XC92]

No, but I tried blowing through all 3 ports. I just put it back the way it was. I'm curious if other 1Gb turbo DSM owners have a similar setup, although of course many have replaced the original hoses by now or removed them if they deleted certain emissions parts. It's probably not a big deal but I'll try to look further into it.

It does seem odd. Perhaps a service station I went to years ago put it in for some reason. I have been having idling issues so perhaps it's part of the reason why. I might try to replace it with a non-constricted splitter to see if it changes anything or fixes the idle issue.

 

[dwb]

My 1ga had the same splitter but it was just that - a splitter with no restriction. I ended up replacing it with a standard T fitting when I replaced all my vacuum lines before I decided to delete the emissions stuff. I'd have to look, but I might still have my original splitter in a box just like yours I could test.

TBH, you should think about replacing all your vacuum lines. They look to be on the verge of dry rot and might be contributing to some of your idle issues. Have you boost leak tested recently?

 

[XC92]

My 1ga had the same splitter but it was just that - a splitter with no restriction. I ended up replacing it with a standard T fitting when I replaced all my vacuum lines before I decided to delete the emissions stuff. I'd have to look, but I might still have my original splitter in a box just like yours I could test.

TBH, you should think about replacing all your vacuum lines. They look to be on the verge of dry rot and might be contributing to some of your idle issues. Have you boost leak tested recently?

I just replaced nearly all of them. I didn't have enough new hose and had to reuse some of the old temporarily until I bought some new hose. Just got it today so I'll replace the rest soon. This is a photo I took before I removed all the intake-related stuff. It's all cleaned up now and I replaced all the gaskets and such. When I'm done I'll do a boost leak test.

 

[dwb]

Here’s what I removed and replaced with a normal T. No restrictions in either one.

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[XC92]

Here’s what I removed and replaced with a normal T. No restrictions in either one.

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I just reused the old splitters as they appears to be in good shape, but I might replace them eventually. I basically removed and overhauled anything intake or exhaust related, including the turbo and intercooler, so it was a pretty major project for me, and I punted on a few things towards the end as it was dragging out much longer than I expected and I just wanted to get it done. I'll revisit this later this year. It's also way too hot here to work outside, in the mid 90's. I tried earlier today and feel completely wiped out.

 

[dwb]

I happened to be looking through some of my old parts that I removed from the Talon a long time ago and found exactly the same splitter as OP, plus another one that is very similar. Definitely a restriction on one leg (with the white mark). I can't say I know what lines either one were attached to or why one had any restriction.

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[petrosian]

I still want to know if it’s a check valve or just a piece of plastic with a smaller hole.

 

[dwb]

I still want to know if it’s a check valve or just a piece of plastic with a smaller hole.

Just a smaller hole.

 

[XC92]

Thanks all. I just reconnected everything the way it was before. Car runs ok but still stalls sometimes on idle, especially while turning in reverse.

I wonder if that's intake or vacuum-related or perhaps due to a weak battery or faulty alt or power regulator?

Or maybe this constrictor has something to do with it and I should swap it for a non-restricted splitter as per the FSM and vacuum diagram sticker on the underside of the hood?