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Old 12-14-2022, 08:12 PM   #1
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Vacuum line mysteries

Dear All,
Just a quick background story: I ended up selling the Blue Boxster as a roller and bought a very cheap but working 2001 Boxster S tiptronic. It seemed like a no brainer to buy a running Boxster S for less than I could sell the blue base model for with the blown engine. In retrospect, it wasn`t a very good deal as it has way too many problems even though it runs. I`ve been tackling the numerous error codes the car had so I can get it smogged and by now I managed to narrow it down to the usual two codes related to the SAI (P0410&1411). All components checked out so I was just gonna replace the leaky vacuum lines but I`ve run into a few weird things that made no sense.

I believe this change-over valve (encircled, picture taken from this excellent thread: Vacuum Confusion -SOLVED - thanks, 78F350) belongs to the cooling valve on the transmission, however it`s connected to the resonant flapper vacuum valve.. I assume the previous owner messed a few things up nd now I have to sort things out. The cooling valve on the transmission is not connected to anything. Question: what does it actually do? And, being unconnected for a while, should I be worried about the transmission?



And, just to clarify, this changover valve belongs to the resonance flapper actuator, correct? (it receives the vacuum feed line but it`s not connected to anything).



Thanks for any input.

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Old 12-15-2022, 05:05 AM   #2
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I don't know about your second question, sorry.

There is a vac line to the valve on the Tip. When the tr anny fluid reaches a certain temp it activates that valve which then opens to route the tr anny fluid through the tr anny cooler... just like the oil cooler on the engine. Matter of fact they look the same although for the tr anny I believe it won't fit an "S" cooler.

Can the absence of the cooling harm the tra nny? Likely, as "heat is the number one killer of tr annies".

If I am incorrect surely JFP will chime in sooner or later.
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Old 12-15-2022, 08:25 AM   #3
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Here's a quick sketch of the 986 Vacuum system:


I am not certain, but I think that the default position of the valve for coolant on the Tiptronic is to flow coolant. If that is the case, it will cool the transmission if the vacuum system is not connected. That would be a smart fail-safe design ...not sure though.

Here's my new Fauxrari that I got in a 'draw a random key from a hat' car trade. (Totally unrelated but the cost of seeing my vacuum advice)

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Old 12-15-2022, 03:54 PM   #4
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Thanks, Guys. The Mitsu GTO (or Dodge Stealth??) looks awesome. I`d get rid of those Ferrari stickers and go back to stock. What`s your plan with it?
'draw a random key from a hat' car trade - is that a real thing?
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Old 12-16-2022, 05:13 AM   #5
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Quote:
Originally Posted by Homeoboxter View Post
... 'draw a random key from a hat' car trade - is that a real thing?
It was real. I'm part of a couple 'Gambler 500 Rally' groups and this was the first time we did it. Only 4 cars were swapped, but it went well and we plan to make it an annual thing.
Rules:
1. Must be running and driving.
2. Must be “legal” for the the road.
3. Must have a title in hand.
4. Must accept what you get. No complaints.

I'm giving the Fauxrari (Mitsubishi 3000GT) to my daughter and son in law after I fix a couple minor issues.
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Old 12-16-2022, 10:59 AM   #6
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Haha, that must be fun! What did you toss into the hat?
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Old 12-16-2022, 12:06 PM   #7
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I traded a '98 Honda CR-V. It's got four documented rebuilds on the title from collisions, but still has some good miles left in it:


Here's the car I'll be using starting next spring after I harden it a little more for off-road use.


...So, pics of your new 2001 S?
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Old 12-16-2022, 08:30 PM   #8
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...So, pics of your new 2001 S?
Just this blurry one with its predecessor. My iphone is dying and makes only blurry pictures. I`ll take a few better shots maybe this weekend.



The car was throwing a P0160 code because there was something wrong with the connectivity between the post cat oxygen sensor and the DME. I fixed that temporarily with this nice additional pink wire:



Now I found out what was actually wrong:








So there`s some progress
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Old 12-16-2022, 09:47 PM   #9
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Just this blurry one with its predecessor. My iphone is dying and makes only blurry pictures. I`ll take a few better shots maybe this weekend.

Now I found out what was actually wrong:



So there`s some progress
would be very interesting to learn what caused this damage. Is there something metal under the cross air runners that could chew this up when engine is runnig?
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Old 12-16-2022, 10:18 PM   #10
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I suspect the flapper valve lever somehow rubbed against it. I`ll take a look at it when I put it back on.
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Old 12-17-2022, 05:01 AM   #11
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It's right under the flapper, so that's likely. Still, check the wiring to the knock sensors while you are there - if it was a rodent, they almost always seem to chew the knock sensor wires first.

From old posts:



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Old 12-17-2022, 05:10 AM   #12
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It's right under the flapper, so that's likely. Still, check the wiring to the knock sensors while you are there - if it was a rodent, they almost always seem to chew the knock sensor wires first.
Ain’t that the truth! Those wires must have peanut butter flavored insulation on them. I learned to solder properly (Dad was an MTS at Bell Labs) in the late 60s, and repairing that damage was absolutely the most touch and go job I have ever attempted.

Last edited by tcoradeschi; 01-17-2023 at 08:11 PM.
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Old 12-21-2022, 08:42 PM   #13
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Took me 2 months to fix all the codes but finally this thing passed smog! I got new plates at the DMV today. Ready to rock! There`s still a lot to do though. Here`s what it looks like.









Messed up the driveway. It leaks oil pretty much everywhere..

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Old 01-15-2023, 05:59 PM   #14
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Originally Posted by 78F350 View Post
Here's a quick sketch of the 986 Vacuum system:

...
My replacement 3.2 is slowly advancing to the point where I can install it in the car. While it is on the engine stand I decided to test the vacuum lines and found it rather daunting till I saw this diagram. Now it looks fairly simple. Thanks a lot.
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Old 01-05-2024, 11:06 AM   #15
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Smile

Quote:
Originally Posted by Homeoboxter View Post
Just this blurry one with its predecessor. My iphone is dying and makes only blurry pictures. I`ll take a few better shots maybe this weekend.



The car was throwing a P0160 code because there was something wrong with the connectivity between the post cat oxygen sensor and the DME. I fixed that temporarily with this nice additional pink wire:



Now I found out what was actually wrong:








So there`s some progress
My car will start and run but anytime I accelerate, it dies and I can’t hold the pedal longer than two or three seconds. I can rev high but then again it dies. I think it is a vacuum leak as well. Any chance you took pictures of the connection points for the tubes and the pink wires?

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