MkII 996 vacuum line routing and related components

I'm in the process of replacing my AOS and the starter cable so I have the left intake manifold off the engine ('03 C2 coupe manual transmission). While I'm in there, I decided to refresh my vacuum system and replace all the vacuum lines, the rubber Y's and elbows, the vacuum reservoir, and the two changeover valves. All that for only $130. The stock vacuum line is available from Porsche for a few bucks per meter and you need about 1,200 mm. You can also replace them with your favorite vacuum hoses. I stay with stock lines since they hold up surprisingly well and they are light and less bulky. Stock vacuum hose line P/n 00004320501 (1m) I just want to document the info here hopefully helping the next guy. Porsche996-vacuum-lines.jpg My stock vacuum lines are still in very good shape as far as I can tell but the problems are all the "Y" and elbows. They are not sealing the best. Also, the vacuum reservoir is leaking slowly while tested with a hand vacuum pump. I also tested the changeover valves and they are all good. The system is very simple. The vacuum is supplied to the one-way check valve from the intake plenum then it branches off to the vacuum reservoir and changeover valve #1, which powers the intake resonance actuator when electrical power is supplied. The vacuum reservoir then supplies vacuum to changeover valve #2, which powers the SAI one-way check valve that opens whenever the SAI pump is running. To check the system quickly, you can use connect a hand vacuum pump to the black/white valve and create vacuum. Then you power each changeover valve and you should hear the resonator flap rotates and the SAI valve moves as well. To check whether the WHOLE system holds vacuum, remove the black/white valve and connect the pump there and start pumping. Vacuum level should stay once you reach some vacuum level and stop pumping.

Excellent info, especially since i was contemplating rigging up a home made smoke machine to do a vacuum test on my car.

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I built one a long time ago but never have a chance to use it yet See my design here http://www.garagejournal.com/forum/s...&postcount=140 IMAG0589 (Large).jpg IMAG0590 (Large).jpg IMAG0592 (Large).jpg

Thanks for the info!

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That's a lot more sophisticated than what i had in mind, looks good! I was gonna just use the old Home Depot 5gallon pale with a lit cigar in it and a compressor

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Or try this Finding Engine Vacuum Leaks With A Cigar - YouTube haha

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Yea, that would be the "manual" mode on my contraption (now i have to add a switch)

Leak found at bottom of the vacuum reservoir at 6 PSIG. image.jpg

Great write up Ahsai. I've been struggling with codes p0491 & p0492. Knowing that you replaced all that for about $130, I may do the same. The dealer has tried, but been unable to make the codes go away. They replaced a hose they thought was cracked, which made the whirring noise I heard at 80+ mph go away, but the codes still came back.

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Yea, I got all the parts from Sunset www.porschepartshub.com Do you hear your SAI pump running at all? Your codes indicate that both banks dont see fresh air. Once you remove the parts I show here, you can attach a vacuum pump directly to the SAI metal one-way check valve on top of the engine, apply power to the changeover valve and blow in the hose that's connected to the SAI pump (after disconnectimg it from the SAI pump end). If you can blow through, the SAI valve is working and the fault is likely at the rest of the system where you can test each part individually.

Hi, I was also getting those codes and found some leaks and a bad solenoid using a hand pump - see rennlist.com/forums/996.../802749-quest-of-the-vacuum-leak.html I cleared the codes but they soon came back. When installing some Fabspeed cat bypass pipes, I found that one of my cats was loose and was hitting the O2 sensor. For me, I think this was causing these codes. The codes are gone but I have a new one due to the cat bypass. Steve

Yes, the SAI changeover valve is definitely a suspect. Btw, there's an updated version of those two changeover valves - p/n 7PP906270 (non typical Porsche p/n).

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Yes, the pump definitely runs. Dealer receipt basically says (paraphrased) checked SAI pump, checked checked SAI valve, checked RKAT values, pressurized system and checked for leaks, replaced hose.

"Dealer receipt basically says (paraphrased) checked SAI pump, checked checked SAI valve, checked RKAT values, pressurized system and checked for leaks, replaced hose." That's shorthand for "We didn't do **** except replace a cheap vacuum hose, but we charged you a crazy price for it, and also for the time we spent not finding any problems - but the book said it should take 3 hrs. @ $150/hr. so..."

I have just replaced a couple of the lines. If the lines are longer than specified, would that contribute to a rougher rev from 1-2k rpm?

I can't think of a reason why it would as long as there's no leak.

I wouldn't think so either, but wasn't sure.

Ahsai, Great photo of the vacuum system. I have been bewildered by the rats nest of brittle vacuum lines .Your photo is a great help.I had been collecting every post I could find to try to piece together a full ,captioned photo of the entire vacuum system -correctly configured. Thanks for taking the time to post this for us.

Glad it helped you!

thanks for the breakdown, this is my next project. My cel comes on when sitting in traffic but never when i am moving so the vacuum system must be searching for something.

Just wanted to say thanks for the picture!!! I broke a vacuum line while putting my alternator back in after an oil filler tube replacement. Then managed to pull the line loose from the intake resonance flap actuator. I knew I would figure out what I did here. Now that I know what I did time to collect parts and plan some down time.

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Others may find this video helpful.It is for a 986 but is generally the same. Porsche 986 Vacuum hose replacement - YouTube

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How do I access the vacuum lines. Do I remove the alternator and even then my hands go nowhere near the lines and Y junctions. Is there a way from behind the rear seats or from under the rear end? Hopm eyou can help me out here Ashia. Thanks.

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Yes, you need to remove at least the alternator. If you need more room, you can remove the throttle body as well.

Access & visibility under the inlet manifold is a problem. I have a useful, peculiar tool to help. Kobalt Snake Light 15" LED. Not the hypercoil - that is too big. The idea is to get the brightest ,smallest LED you can . I found one with a mirror attachment .Have not tried it. Amazon Amazon Any tool purchase is better than removing the inlet manifold ! Let us know how it goes? FYI I just ordered this (with 33LED lights!)for working in the same area. In theory I could use a borescope+laptop but that seems odd. Amazon Amazon

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I accidentally knocked a vacuum line off when changing my alternator. I found it easiest to access it by removing the throttle body....and MUCH easier than removing the alternator...took me forever to wiggle the alternator out the first time, no way I was going through that again. Took 5 mins to remove the throttle body.

The problem with the alternator removal is usually that pesky bushing at the back. It tends to corrode in place. If you can remember when you have the alternator out - put some grease on it.

Yeah, those bushing are tight and so is space around it. LOL

I have had my alternator out 4 times already. Also the Throttle body and idle body to clean both and replace with new gaskets. Tricky but doable. Found a broken vacuum line and joined it making it longer with fish tank air supply line. I would like to replace all lines as Ashai did. I do have a scope with LED light and hand held monitor but the dam thing is so hard to twist to see the Y junctions and what ever else. I shall persist and do the job eventually. ASHAI I had the idle valve in my hand. Can you tell me if the idler beveled door should close completely or is it always a sixteenth of an inch open with power off. I see it open fully when I add power from plug with ignition switch in the on position.

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Referring to Idle Air Control Valve? If so, when you use current to activate the rotating valve, it never quite fully closes.

ashai.. Am I looking in the wrong place for a leak to cause PO1124 and Code PO1126. I am in behind the alternator changing air lines and testing change over valves. Should I be looking somewhere else for air intake leaks. Where would you check? Thanks.

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Hurdi, there are a few things you can try: - check the oil filler tube for cracks - check all the intake rubber boots and hose clamps - smoke machine on the intake - use a hand vacuum pump to test ALL vacuum hoses. Also remove the vacuum tank and pressurize it for a few PSI then spray soapy water over its bottom. Mine has a very small invisible crack - spray carb cleaner CAREFULLY around all the intake and fuel injectors and pay attention to any engine note change. Don't spray it on any hot surfaces such as the exhaust!! Have a fire extinguisher ready at hand - use a scanner that can read the pre-cat O2 sensor voltage in real time. Monitor that when spraying carb cleaner and see if the voltage pegs at high (1v) - remove the regen valve and bench test it

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how the hell did you manage to get to the vacuum canister Ahsai? Better still hold it in your hands. Even with the Alternator out I cant get to mine. It's hidden behind something else. I know it's there I saw it with my led lighted wand thingy. I need to test for leaks on all of my Evap lines around there including the canister. I only hope that's it is not leaking. The rest of the system I can manage to get too. Well I think I can lol. I borrowed a vacuum pump from Autozone for free. Isn't life fun?

I had my left intake manifold off at the time for AOS replacement. Have you tried removing the throttle body and the T-plenum? That should give you more space to work with.

Here are a few ideas subject to Ahsai's approval because he is the one who pioneered the Vac accumulator crack discovery: The leak will be worst when the vacuum is highest. So at idle speed. It may be better/worse warm/old so try all permutations. As you discovered, it is buried so deep you can barely see it and you certainly can't feel any crack - even if you could reach it - which you can't. You can't run the engine with the alternator off so when you have finished inspecting under there for disconnected hoses/split hoses - put it back. Try carb cleaner or propane. If you fit a small diameter hose on the propane you can be quite precise with it. The alternative is to remove more parts and then apply a vacuum with a Mighty vac. WAtch to see if it holds/looses and start from there.

Thanks Schnell and Ashia. I changed ALL my secondary air vacuum lines for new rubber ones. Lengthened a couple of them. Used the same elbows and y junction. Sucked and blew on them and they hold vacuum on the tip of my tongue. The fish line tube I used was drawn flat with vacuum so that's why I changed everything to thicker rubber which does not flatten out with vacuum in it. The black and white one way valve that goes to the intake plenum, does that draw vacuum when the engine is running at idle? If so there maybe a small leak on the vacuum canister (which I cannot get too) letting unmetered air into the system and out via the black and white valve to the plenum which could throw codes P1124 and P1126. Even though the secondary air fan is not running after a couple of minutes. YES??? If so I need to get to that vacuum tank.

Vacuum tank = the hairline crack is usually on the bottom of the tank from what I have read. It is so awful to get to it - replace it anyway ? After all these years and heat cycles it is close to failure anyway ? The vacuum lines - I hope you did not use "rubber" . The choice of materials is critical. Regulr silicone hoses may collapse under vacuum. The thick wall silicone hoses may be good. They are certainly much more heat resistant than the soft vacuum lines that are OEM.They are also less likely to crack than the hard-plastic lines. The large 'S' shape hose from the SAI pump never seems to fail. I have seen lots where there is no clamp on that hose at the pump and it seems to work fine. But most important , thanks for completing the Post.So often Posters just stop and we are left not knowing exactly what fixed the problem. There should be a way of black-marking such non-responders?How else will we improve the knowledge base for other Forum Members? Equally, bad advice given should also be noted .

Ahsai: Thanks for taking the time to post the the vacuum diagram. It's very helpful. I love Rennlist. I replaced my alternator a month ago. It went well except that I broke one brittle vacuum line going to the resonance flap actuator AND lost the line that goes to the vacuum reservoir. I spliced in a new section of line to the resonance actuator using parts from Pelican: *A straight connector 999-239-040-40-OEM * Vacuum line (sold by the meter): 000-043-205-01-M20 I'm getting error codes for the secondary air injector (SAI) not working. This is because the vacuum line must have pulled out of the Y connector and I can't find it. I have the Y temporarily plugged with a golf tee. See photos below. The new vacuum line is white. Can someone post an explanation or photo showing where the vacuum line goes from the Y to the vacuum canister?

Dr, the line from the Y to the vacuum canister runs on top of the alterantor. You can see it in the photo of the 1st post (the 360mm one). The one you plugged should connect to the black/white check valve on the T plenum left side. How's your engine running btw? No more issues, right?

I found the missing vacuum line right where you said it should be, atop the alternator. Thanks. There are two lines that go back into the bowels of the engine together, one for the vacuum canister and one for the vacuum flap. I think I have the right. The ECU will let me know. My engine idles much more smoothly now that I had the valve lifters replaced and the reinstalled the old fuel injector myself. About a third of the time it's perfectly smooth. The rest of the time, it's a little rough. Next I will investigate the source of oil on the rear barrel connecting the two intake manifolds. After that I need to find a new oil leak somewhere near the front of the engine.

Sounds like the engine is still keeping you somewhat busy. Could the oil leak around the intake a sign of bad AOS?

Going under the car, the leak seems to be from the engine-transmission interface, so I'm guessing the rear main seal (RMS). For the oil on the rear barrel (toward the back of the car) connecting the two intake manifolds, could that be from a bad AOS? There is no oil inside the throttle body, but there is a thin film of oil inside the closest barrel to the throttle body.

Yea, that sounds like the RMS or the IMS flange seal. I think you mean the intake T plenum right behind the throttle body? A thin film is fine but there should not oil drops. The throttle body would be dirty even if the AOS is bad. Best is to use a manometer to check the crankcase vacuum.

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I had to remove my alternator in order to replace the regulator. In the process, I decided to remove the bracket for the changeover valve. In the process, I managed to disconnect both of the vacuum lines that attach to the "Y" joint. I found the 122mm hose from the check valve on the intake -- no problem, just reconnected it. The 428mm line is still in place, so no problem there. However, I seem to have lost the 360mm from the vacuum reservoir and I'm having an awful lot of trouble locating it. I removed the alternator again, but still can't find the line in order to reattach it. Any suggestions on where to find it or how to access it? I am going crazy with this project..

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Ya, I had the same problem, losing mine. It turned out to be hanging just above the alternator, back a few inches where it wasn't visible. I found that both of the long vacuum lines were a little short (especially after one cracked), so I bought some vacuum line and couplers from Pelican and a local shop and extended them. The photo below shows the new vacuum line, which is white. You might be able to infer where the lines originate from the photo. If you can't find the original vacuum line, you could just run another one. Routing from the vacuum canister to the back of the engine, then past the alternator to the front would be really difficult with the engine in the car. I'd suggest just running it from the canister to the front. It won't be as pretty, but you can see what you're doing. The new extensions to the vacuum lines are white.

I recently did this tedious job and have a different approach that more qualified M96 guys may have comments on -s o heed them not me ! The small diameter vacuum hose is very brittle after so many heat cycles.It easily cracks when manipulating it during re-installation. O.K. if you notice at the time but not so good if you get an SAI code or Flag after you have reassembled it all ! If you try to separate the oem vac line from any of the 'rubber' boots/connectors you may find it is glued on and if you twist it off to repair ,another break/crack occurs. I decided to replace as much as possible of the entire system with USA-made(Samco) 3mm silicone hose and BRASS connectors/fittings/adapters/splicers. If you search EBay for "4mm Hose Barb Fit Brass coupler Splicer Connector fitting" or the Imperial equivalent 3/16 " you will find "Y's" , Cross, "T", straight adapters and more.Yes, it is tedious hunting but the brass/silicone combo will last forever and you will never have a vac leak in this part of the system again! . Make your own measurements, Be ready to convert sizes mm/" and remember the good quality black silicone hose(probably 3mm) is very stretchy and flexible. Cut it long. And do not forget to pressure test the Vac reservoir under water for leaks in the seal at the base. Otherwise you will need to re-do. If part of the reason/problem for your vacuum line work was an SAI code/Flag ,there is a beta SAI delete hack circuit on 986 Forum that solves it. There is a related beta circuit for inefficient cats to 'help' the post-cat O2 sensor give a get-you-to-pass Smog Test

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Thanks! I was able to find the hose, it was pretty much where you said. Of course, I dropped one of the bracket screws in behind the motor.. All back together now, though. Good as new!

You gotta love Rennlist.

Thanks for this Duncan. While changing the alternator, I pulled out the line going from the change over valve to intake resonance flap actuator. This diagram was very helpful. How did you reattach the lines? I got it done, but it felt pretty crude and really lucky. I lowered the engine and was able to pull the rubber part connected to the resonance flap by reaching over the top of the engine. I reattached the line from the top and started threading it back down while flashing a light underneath the distributor hose. I was barely able to fit my forearm over the top of the engine to do this. Once I saw where the line was, I shaped a hook from wire coat hanger and i fished it out towards the change over valve.

Glad to hear that this thread helped. I had the plenum off at the time so I had good access to all the lines.

I have a 987.2 and have owned it for a year. Just had the clutch, double mass flywheel, RMS, water pump, idler pulley, and serpentine belt replaced by local IDY. Les than a week after the repairs there is a cel with both P0491 and P0492 displaying just 18.2 pressure. Is the vacuum reservoir behind the front access panel or the rear. I am guessing the intake actuator is near the air filter. New Porsche DIY.

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This video should help https://www.youtube.com/watch?time_continue=814&v=go34DJAuPyg Also check out the Boxser forum on RL here. Maybe more replies there.

Hi Guys! Sorry to resurrect this very old thread (almost 10 year old ) It seems that we all have messed up the hoses when we change our alternators! I think it's really not our fault because as time goes by, these vacuum hoses (rigid types) tend to get brittle.... so it's really Porsche's fault! I just have a question to the OP if he's still around...and I apologize in advance if I may have missed the answers within the posts. I included this picture to explain more what my queries are... 1. Regarding the Y Connector encircled a the bottom, I seem to have lost mine, I can't see it anywhere. Is the Y Connector really attached DIRECTLY to the Changeover Valve #1? 2. On the Black & White check valve thing, I also seem to have lost this part and plan to purchase one now. Is the line really this short? Because I seem to not see this valve anywhere in the engine bay as well..... and which intake manifold does this connect to? 3. Lastly, there are 2 intake plenums on the engine bay driver's side; one in front, the one nearer the cabin and one towards the rear, the one closer to the back of the car. Which one please? I also got confused with this other post on P0410 and P1411 error codes tackling almost the same issues because in the diagram...there was no Y Connector directly connected to the Changeover Valve #1...Strange! Hope you guys can help out. Our cars are now 20 years old ++ and people are starting to get all these issues that you've experienced earlier. Hope to hear from someone. TIA!

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It should not, On MAP sensors, that are remote mounted on some engines, the lines are up to 5 feet long. A engine guy I used to work with told me vacuum in those lines move way beyond super sonic when measuring pressure, but Diameter will affect the speed a vacuum activated valve opens. so I'd assume if your taking about the line to the x-over valve from the solenoid valve if it was really crazy longer it might affect the operation, I doubt a inch or two would matter. I would first vacuum test the solenoid valve and the changeover valve to see that they hold and the solenoid valve releases and retains pressure when activated (Bench test basically) you'll want a mighty vac hand pump or similar. A vacuum leak or a tired coil would both cause low rpm stutter..

There is actually a vacuum diagram under the deck lid of your car showing the specific diagram for your particular model...The black and white diagram shown above is for a Boxster 2.5 engine that doesn't have a secondary plenum with the resonance flap...That could be part of your confusion... That said there is only a few vacuum lines and valves on a 996, it's a very very simple system compared to the late 70's cars ( at the peak of emission controls without EFI) that had 50 feet of vacuum lines and dozens of vacuum valves with dual,triple, vaccum tree's and at least a half dozen "t's" "y's" and "4-way's".......... they were a literal nightmare !!!

Thanks so much. I did a whole day googling pictures of various intake manifolds and vacuum systems and came across tons of pictures that explains what connects to what. Still very confusing. I hope i'll be able to figure everything out when I take down the intake manifold and guided by the pictures and write-ups on this thread. Will also post pictures here so that people can learn from it. Thanks Doc!

Sharing critical infos and things I have learned.....This picture really helped me...a picture post from Dbjoe996 posted some time May of 2020... Thanks to Dbjoe996 for this! And this one from ebay... This one from an ebay post of an intake manifold for sale

Can you tell us what this video was about? I have a PO660 code (without CEL but discovered with Durametric) in my 03 Boxster S with the M96 3.6 out of a Carrera. So I am looking for as much as possible before I go pulling plenum with the foreknowledge that everything will be somewhat backwards or flipped due to engine orientation.

I'm re-installing my engine after a rebuild and have noticed that my vacuum lines don't seem to have the same routing as in Ahsai's photo with the red background above, nor do they seem to match the diagram of the sticker on my trunk lid. Here are my variables: it's a 2002 C4S and it has PSE, but at some point in it's life the previous owner changed to an X-pipe and I believe abandoned the PSE system (at least that's what he remembers being done and if I push the PSE button, nothing happens). Additionally, it's been enlarged to a 3.8L, although I'm not sure if that matters. My Questions: 1.) Is it possible that someone before me changed the routing for some of the hoses in a way that doesn't resemble the example above, nor the diagram, but everything EXCEPT for the PSE will still work correctly, or is there ONLY one way to connect these hoses? 2). If the lines (with the metal shielding) going to the muffler actuator valves are necessarily being used, should they be plugged up? Thanks

1. Best to stick to the layout you can reference at a later date if required. 2. They need to be plugged.

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Understood that it's "best to stick to the layout" but that's not my question. Is it possible that the "system" can still operate correctly if the vacuum lines are routed in a different manner than what's suggested? In other words, is it a sequential system, or non-sequential? And FWIW, I noticed that the stock layout with PSE shows a 4-way "T" coming off of the vacuum canister, but the non-PSE systems only use a 3-way "Y" connector. Mine just has a "Y" so obviously something is different.

It's not sequential, you can plug/route it every way you want as long as everything is connected to the vacuum reservoir. You must have the check valve in the line between TB and which ever part that is connected to the vacuum line after that, however. HTH

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Thank you. This helps more than you know.

Am I correct in assuming that the entire vacuum system that is used for enabling PSE is an isolated system that can simply be disabled without affecting the rest of the car? By disabling, I mean eliminating the vacuum line that feeds the system either by plugging it off, or by removing the "rubber sleeve with connecting nipple" that gets added in between the tuning pipe and intake (as seen in the diagram below). My thinking is that I'm spending all this time trying to get this system correctly connected when it's actually never even been working since I bought the car. Also, if plenty of cars don't come with this, then the whole system is purely additional, and thus can be eliminated - correct?

Yes just put a cap on the plastic hose that goes to the change over valve. its just a vacuum source.

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DeJeeper - Thanks for thee quick reply. Wouldn't it be better to cap it off at the place where the nipple comes out of the manifold rubber connector, or the check valve as it's the first object that is inline? The check valve (aka switch over valve) is farther down the line. It seems that the more potential areas that could leak (especially the second vacuum tank which is known to have hairline leaks) the better? No?

Of course it would be best to buy a 3 way splitter and replace the 4 way splitter behind the alt but it depends in how far u want to get into it. Just preventing a vac leak anywhere will fix the problem so terminate where u can/want.

UPDATE: So with the help of a borescope I was able to confirm that the vacuum system, let's call it the primary system, is connected the way it should be (the same as in Ahsai's photo with the red background above). I've also figured out via a post a year ago by @Dharn55 that included the Porsche installation instructions how the PSE system is supposed to be routed and how my system was routed incorrectly. (Maybe that's why it never worked). Also, that despite my earlier thought, there is only supposed to be a 3-way rubber connector off of the cannister, not a 4-way as I thought. All that being said, I still have the same question: as long as I plug up the vacuum line coming off off the rubber connector at the manifold (see black arrow in the illustration below), am I safe to not use the PSE vacuum system, or does it have a secondary function?

How about draw and label a simple diagram of the proposed system you want to use...showing all components labeled I can quickly tell you if it will work or not.. or it will leak...lol ..There isn't a lot to it so should be easy to draw a diagram, and be much easier and precise than back on forth on each connection... Like said you can route things like you want and there is 100 ways it can be right ( and 100 ways it can be wrong)

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Here you go. Can I plug the line that is circled in red where there is a port out of the rubber sleeve that connects the manifold to the tuning pipe (depicted in the illustration above via the black arrow in Figure 5)? If it only powers the PSE (as I understand it), then I don't see why not. Second question... I read multiple threads about people disabling the PSE via modifying the relay, but why couldn't you just unplug the electronic connector (orange plug) that goes into the electronic changeover valve?

Very nice drawing !! Absolutely you can plug it at the red circle, the PSE vacuum system is separated from the SAI and intake resonance flap so you can disconnect and plug it anywhere along that line.. Yes you could even just disconnect the wiring from the electro-vacuum change-over valve ..

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Thanks Skip! Hopefully I'm up and running some time this Sunday.

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[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/graemlins/thumbup.gif

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Would this photo of the parts be correct for a 2000 996 C2? I checked the diagram on my deck lid and I can kind of make sense of it but just wanted to check Also where did you get replacements for the rubber elbows? Mine could do with changing as one or two look to be split. Already got new vacuum lines and Y connectors ready to fit, just need the rubber elbows thanks

92857471705 Autoatlanta diagrams..... https://www.autoatlanta.com/porsche-...section=107-10

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thank you. Is it just the 4 I would need? Guess it depends if the first posted image by Ahsai is the same for my 2000 C2?

There r several elbows in the system depending on your model and options. Buy 6 and return what u dont use?

Hi - you can buy the elbows and vaccuum line at any Porsche dealer, or give EBS racing a call. The number of lines and connections depends on your car's age and if you have the PSE exhaust or not as it requires a few more lines, switches and an additional vacuum cannister.

So the car is 2000 C2 manual and it doesn’t have a PSE exhaust. Where can I find a diagram for my setup then?

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I gave u the link to the autoatlanta pet drawings. U need to go through them. Its shown over a couple of drawings. https://www.autoatlanta.com/porsche-...section=108-05

Personally, i followed the photograph in post 7 of this thread with success. Post 8 of the same thread also has a helpful diagram, but I prefer the actual photograph.

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thank you, I did check them but it only showed me the first link you posted and the second link. No other variations of the diagram. There�s a 4 way junction at the vacuum reservoir on that diagram but mine has a 3 way Y junction so I presumed it�s the wrong diagram for my car�

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I saw that photograph but it says for a 99 C2 at the bottom and mine is a 2000.

I don�t think it�ll matter.

@911Singh I do believe the year matters as I think there was a change after '99. You're going to have to do what all of us have done - look at photo and diagrams and piece it together. I'm not being snarky, but after 20 years, there's a lot of info out there and some of it is misinformed. I struggled too, but if you look at enough of the various photos, identify which lines are going to which switches, etc., you can then use the diagram on your trunk lid to figure out the correct connections. Ideally, once done, you should smoke test the system for leaks (as a vacuum leak could be detrimental to your motor's health) and check to see that all switches are engaging (using a Durametric or PWIS). Good luck

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Appreciate that. I managed to confirm that what�s on my car matches that of the photo by Ahsai. Was just confused as there�s only one variation of diagram for the air injection system so was beginning to think I was missing something from my setup. Is there a way I can test if the system is holding vacuum by using a hand pump? Would I disconnect the one way valve from the intake runner and pump air into that?

The 4 way vacuum connector is used for Tip cars. I had to plug one of the ports when swapping to 6mt. Just ordered a new 3 way to get it back to all factory.

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Nice one! thanks for confirming. Now I know the diagram thats out there is for with the 4 way connector