Porsche 944 - Vacuum Leak Repair: Parts, Routing, & Functionality Overview

[@emmanuellehuu8818]

Dude... I got an 83 engine in an 87 924S... that's like the worst of every world when it comes to searching for info on what I have, and you just give me strength to continue, thanks a lot my guy, cheers!!!!

[@NC944er]

That definitely makes for an interesting combination to sort through. 😂 Glad you found the info useful!

[@porschewill]

Quite frankly this is a staggeringly brilliant video. My absolute respect to you.

[@dtheopha]

great video - thanks for taking the time to make it !

[@donaldclary846]

That engine is BEAUTIFUL

[@NC944er]

Thanks! The intake manifold and camshaft housing have been bead blasted and powder coated with satin clear. Many of the steel parts on display have been either replaced or re-plated with yellow zinc.

[@pierremartin9048]

This is PCA reference quality stuff. Your level of understanding and ability is truly incredible.

[@NC944er]

Thanks Pierre! I put a lot of research and effort into this one. I’ve actually referenced it myself when my brain gets tired. 🤣

[@siegeperilous8156]

@NC944er You're one of the reasons that KZbin is such a great resource! To save time, and since I don't like fiddling with the JPT connectors alot, I leave the electrical connectors attached to the fuel rail and just lay the whole thing over . Just the 2 vacuum lines and four bolts, and pop it out. =) Keep the content coming!

[@michaelsliwinski8044]

Thanks for sharing! Your effort to produce these videos is greatly appreciated.

[@P1983sche]

Man, I am glad you made a comment on my channel because your channel is very helpful. I am working on all of the rubber components now on my engine. Thanks 🙏

[@NC944er]

Awesome! I’m glad to hear you’re finding the content useful! 👍🏼

[@BenCarpenterWrites]

Thank you so much for this!! New ‘87 944 NA owner with some running rich and rough start issues. Excited to dig into the vacuum system today with this knowledge!

[@Kptgibson]

I learned alot by this video and it was just fun and relaxing to watch also.

[@autobreza7131]

Great video. Your knowledge is quite extensive. Suggestion - use the term “vacuum” or “negative pressure” rather than “vacuum pressure”. It’s more precise and clear.

[@nelsonhugs1383]

Such a great video. You have wonderful pace with the instruction. Thanks so much. My Porsche 944s will be happy. just a side note did you have to bleed the breaks? because you disconnected the booster line?

[@NC944er]

Awesome, thanks Nelson! 👍🏼 The hydraulic brake fluid system is contained separately from the vacuum system, so there’s no impact to the brake lines that would require bleeding in this case. The brakes will still function with the booster vacuum line disconnected, they’ll just be super hard to press. That’s where the power/assisted braking idea comes from, the vacuum system simply makes it easier for us. 😁

[@shanerobert2032]

Great video very detailed explanations thanks

[@ToleranceForNonsense]

Brilliant video, thanks!

[@HootisGarage]

Thank you.

[@phillippasena1429]

I agree, nice video again, in order to replace the smaller lines, do you have to remove the cover? Or can you replace the small lines with the cover still on? Also, installed my Lindsay racing fuel rail, I like it. I also installed the Rennbay headlight harness to upgrade the lights, we’ll see what it looks like waiting for the lightbulbs. Next video, changing the transmission fluid. Unless you already did it.

[@NC944er]

I’ve never tried it that way as you lose the benefit of being able to inspect all the other hoses and parts below the intake manifold, but I suppose you could do something like stretch out a metal clothes hanger, tape a new line to the end, and push/work it down under in the right direction. If you have success, let us know. 👍🏼

[@etyl2494]

Great video! Would appreciate a list of tools required for the job with your videos. But idk maybe it's just me because I'm not very experienced :D. Just a suggestion.

[@NC944er]

Thanks! Most of the work presented on the channel requires basic metric tools, sockets, etc. I do try to mention when a specialty tool is required, like in the case of the timing and balance shaft belts.

[@Krappolol]

Amazing content again. What about smoke testing? My 89 S2 has random horrible starts, I’m suspecting vacuum leak somewhere. It requires 5 seconds key cranks and a good throttle push. Once started, rpm go up and down to the point of stalling sometimes. I have to maintain a bit of throttle for 2 more seconds to avoid stall. Then engine idles great and engine runs great. Up for a troubleshooting pattern ☝️ Cheers!

[@NC944er]

Beyond visual inspection of the lines and connections, you’d have to invest in an Evap/Vacuum Smoke Machine leak detector. They run about $100-$200 - www.amazon.com/Vacuum-Smoke-Machine-Detector-Automotive/dp/B0746SL9D6 Otherwise, a reputable service shop could run the test for you for about $100 or less. There are a number of videos out there regarding the process, but it basically involves pumping smoke into the system and observing any escaping smoke from the lines/connections that should be holding vacuum.

[@zanastumasonis]

thanks for the video, someone deleted a bunch of stuff from my 944 and now I have to undo it all... ugh

[@NC944er]

Oh man! Sorry to hear that, but it does happen. Luckily there are plenty of parts still available for these cars. Best of luck!

[@mikewalters8253]

So is your engine looks brand new, did you replace everything

[@NC944er]

Hey Mike, the engine bay restoration is a combination of zinc plating all the steel brackets and supports, powder coating the cam housing and intake manifold, and replacing quite a few rubber lines and associated hardware. There’s an engine bay restoration video on the channel here outlining more details if you’re interested - kzbin.info/www/bejne/Y6jUmKWOh7mmrqM

[@tims_4x4_garage]

I thought only the turbo cars had the Venturi, didn’t realize NA cars had them as well. Did you do the delete or was it done before you acquired the car? I’m going to do some work under the hood soon and would like to delete mine if it has it

[@NC944er]

Yeah, I think the Venturi was talked about more with the Turbo cars, but the early NAs had it as well. Porsche removed it on the 1988 and later models.

[@tims_4x4_garage]

@@NC944er cool, good info. I do have it, just verified. Read up a bit on it just now. Looks like the turbo cars have a much more complex vacuum system that sees more benefit from a Venturi delete. I am going through the car in stages and seems like I keep finding things I can delete rather than repairing/replacing.

[@944LS]

What size are the vacuum lines? Lindsey racing says 3/16” but is the OD or ID? 3/16” ID looks large to me?

[@NC944er]

Hey man! The OD is 3/8” and the ID is measuring a hair over 2/16” so I’m guessing it’s 3/16” ID installed, as it stretches a little bit. I measured an old rubber OEM connector and it’s right on 3/16” ID. The Lindsey lines fit nice and snug at the connections, I haven’t had any issues with them other than the silicone material is a little “tacky” out of the box, so they pick up a little dust on the outside, but that has gotten slightly better over time and they’re pretty clean and durable.

[@944LS]

@@NC944er Awesome info, thank you for taking the time to provide the measurements!

[@NC944er]

@@944LS Yes sir! I’m not sure if you have an early or a later car, but for a late model, you’ll need to order a bulkhead connector separately if you want to pass a line through the firewall for the vacuum reservoir. My ‘88 also needed a 4th T-connector (Lindsey kit only includes 3), so I ended up customizing the order with 20’ of line and the needed connectors rather than buying the set kit from them, which ironically ended up being half the price of the kit at the time, but it looks like they’ve increased prices on some of the pieces now… for what it’s worth. Cheers!

[@944LS]

@@NC944er I see! I have an 86 NA. I ended up ordering line on Amazon, with Tees, it came out to be alittle cheaper but the lines OD is about 0.43” vs the 0.375” stated. I think it’ll work fine, just alittle more bulky.

[@donaldclary846]

I changed all of my vacuum lines and didn't remove the fuel rail, injectors or intake manifold.

[@NC944er]

Well done sir! I’ve heard that it’s possible…

[@oscarruiz3426]

what sizes are the hoses that connect to the control valve and the venturi. (i know yours doesnt have the venturi but Ive looked everywhere and cant find the sizes)

[@NC944er]

The line going from the J-boot to the air/idle control valve is actually narrower on the J-boot side and widens up closer to the valve so I just bought the OEM part: 944-110-217-00

[@oscarruiz3426]

@@NC944er Awsome! thank you I really appreciate it, great videos btw extremely helpful!

[@nickwade3227]

Do you know why fuel is coming out of the vacuum connection on my regulator? 83 944. Also, the previous owner welded a plate over my thermo vacuum valve. Can I just run vacuum straight from the intake to the vacuum control valve?

[@NC944er]

Welding over the valve, huh… that’s an interesting modification. 😂 If you just ran a direct line to the emissions control valve, it would have supply at times when it shouldn’t, since the thermo valve only opens at operating temperature. Personally, I would replace the curved steel water outlet at the back of the cylinder head so that a new thermo valve could be added back to the system. As far as the fuel leak at the regulator, it sounds like the internal diaphragm has failed, allowing fuel to pass through to the vacuum side where it shouldn’t. I’d look at replacing the fuel pressure regulator.

[@nickwade3227]

@@NC944er thanks man! I replaced the regulator and we’re good now. But what I meant is they welded a plate over the port on the head. I was so lost when I was replacing all of my vacuum lines because I couldn’t find where they led to them I saw that it’s “deleted” I guess

[@NC944er]

@@nickwade3227 Ahh, gotcha! So you no longer have a heater supply and return pathway. A couple options… replace the cylinder head so the proper equipment can be added (expensive) or delete the evaporator/charcoal canister system altogether and run the tank vapor line to the air box (cheap). Here’s a thread on it - rennlist.com/forums/924-931-944-951-968-forum/767541-charcoal-canister-delete.html

[@nickwade3227]

@@NC944er thanks! You’re the goat, appreciate all the work you put into the channel.

[@NC944er]

@@nickwade3227 Yeah man, good luck! The latter option would likely cause the vehicle to fail emissions inspection, if you have those tests in your state…

[@commotoed]

sorry off topic, where did you find the wiring harness loops/anchors (yellowish)

[@NC944er]

Sure! The yellow/orange wiring clips you see here came with the car, but I have ordered some replacements in the past, although they are now grey in color. They are a little difficult to track down, but it's part number: 477-971-851 and here are a couple links... 944store.com/product/477971851/ www.pelicanparts.com/More_Info/477971851.htm?pn=477-971-851-OEM

[@commotoed]

@@NC944er Thank you, I've been reviewing the parts diagram and have not had any luck

[@NC944er]

@@commotoed Yeah, there are a handful of things that simply aren’t on there. 😂

[@johnrichmond4083]

would like to talk to you about a no start issue with my 1988 NA,

[@NC944er]

Sounds like fun. 🤣 They usually boil down to fuel or spark issues, and often in that order. Fuel delivery problems are common because of the lengthy storage periods on these cars - failed pumps and regulators, stuck or clogged injectors, etc. This is a great place to start to dig into things and begin checking items off the list - www.clarks-garage.com/shop-manual/ts-01.htm

[@MrStroller4u]

Dude, get out of my head.

[@NC944er]

🤣