I did but I am now skeptical that it was actually generating smoke. I had made a “paint can” smoke generator and it is about 15 years old and lent to a few friends. I was checking it out a couple of weeks ago and noticed the heater wire is not attached to the power. I didn’t test for smoke output when I used it (due to excitement and not thinking the shop would have left vacuum leaks after replacing all of the tubings, etc). I bought a simple smoke generator that I tested and know generates smoke. I think I need to retest to be sure. Leaks are the only thing that make sense to me at this point.

Ok, well I am seeing a lot of smoke from multiple places.

I had the shop put in a pop up valve in the new airbox. It is leaking. Not where it is glued to the airbox. Pushing down on it doesn't seem to make a difference. I put a rubber glove over it to stop the leak there so I could find others.

I definitely have leaks around the #4 fuel injector and maybe some on the driver's side bank. I gave the shop new injector O-rings and the leak doesn't appear to be coming there - it is coming from the insert sleeve. I also gave them a set of sleeves and O-rings but this were not installed apparently.

Also, there is a lot of smoke coming from around the fan shroud - seems like from below it as you can see in the photo. This is the largest amount of smoke I've ever seen from this car over the 4 smoke tests I've done over 16 years of ownership. Any ideas where this is coming from?

And, there is smoke coming out of the large (~3" D) heater duct (see photo). I don't think I've come across any information about smoke here or sealing it off. Thoughts on this?

Right now the sun is to my back and low in the sky so there is a lot of glare and very difficult to see. I need to wait until dusk and get out my light bar and rerun the test and try to track where the leaks are. It didn't seem like there were any leaks from the front side (towards the firewall). The smoke that concerns me is 1) the quantity of smoke coming from the fan shroud area and 2) the popup valve. The injector leaks I've had before and didn't seem to greatly affect tuning in the past. Although I wanted to get new sleeves and O rings installed while the shop was in there.

Thoughts and recommendations appreciated please.

http://forums.pelicanparts.com/uploa...1730654187.png
http://forums.pelicanparts.com/uploa...1730654187.png
http://forums.pelicanparts.com/uploa...1730654187.png

Not seeing any pictures

and now I know why. I just tried to repost them but they didn't show up again. One was too large so it failed displaying them.

Here they are.

Meanwhile, it has been too cold to work on the car today. Tomorrow should be fine so I hope to dig in and find the leaks. I did order some silicon plumbers putty/tape that I can use to plug things so I can focus on finding leaks. I am mostly concerned about the quantity of smoke coming up the back - seemingly behind the fan and shroud (towards the rear of the car). It is not coming out of the tailpipe. I didn't see any smoke coming from the front (towards the front of the car) of the airbox. All of the vacuum hoses were replaced.

I am perplexed with the new popup valve apparently leaking. Even pressing on it quite hard there was still smoke coming out near the hinge side. Something to investigate for sure.
http://forums.pelicanparts.com/uploa...1730757257.jpg
http://forums.pelicanparts.com/uploa...1730757257.jpg
http://forums.pelicanparts.com/uploa...1730757257.jpg

Pop up valve is installed incorrectly. Your lid would hit the air filter during backfire. Hinge should be towards back of air box.
http://forums.pelicanparts.com/uploa...1730811632.JPG

Thanks Ed - that is how the shop set it up and he's the one that encouraged me to install it. I owned the car for 16 years without one. Of course, the one big backfire I had did take out the airbox!

But, even installed incorrectly oriented, that would not cause it to leak at this point. If I have to replace the new valve because it is faulty, I'll orient correctly.

Just FYI, this shop has a 4.9 star rating and decades of followers. A close Porsche friend of mine (RIP Chris Bennet) had recommended this shop many times.

With Sully on this.

http://forums.pelicanparts.com/uploa...1730814742.jpg

But others feel differently and do install them on top of the fins. Maybe try some caulk or glue on the hinge side just temporarily to see if that stops the POV leak.

Had you just run the car prior to doing a smoke test where these pics were taken? I had smoke from my fan once but it was oil dripping on the hot heat exchangers and wafting up and out the fan.

Yeah, I am going to use moldable silicone putty to temporarily plug leaks as I find them so I can focus on finding them all. The amount of smoke coming up the back though quickly obscures everything. I should be able to get out in the garage tonight and do more investigation, perhaps it is coming from the #1 intake boot (which was replaced but made not clamped properly, etc.

http://forums.pelicanparts.com/uploa...1730817631.jpg

Smoke out through the fan duct usually comes from leaking intake manifold gaskets. The smoke seeps out past the gasket, under the shroud, and out the fan duct.

Thanks Pete. I didn't get a chance to work on the p-car last night but hope to tonight. The intake manifolds were all cleaned as part of the airbox replace, along with gaskets but I will absolutely check them. It did seem like a lot of smoke was around intake #1 so that will be a good place to start.

Smoke coming through fan - what could it be?
 

Ok, I was finally able to do some more smoke testing this morning. I've attached a link to a video that shows it billowing out around the fan blades. There is no smoke coming from around any of the intake gaskets on either side and nothing I can see from outside of the fan shroud.

What can this possibly be? How can I figure out where it is coming from? Do I need to take the fan off?

https://youtube.com/shorts/yCet0CNN6xc

That's a lot of smoke. Before you pull out the fan, look under the car and see if smoke is coming out around the exhaust port gaskets, then seeping up through the fins, then out the fan duct. Otherwise, yes, you will have to pull out the fan to see.

Do you think smoke in this area is a vacuum leak? The car is on the lift so I can take a look underneath in the morning. Thanks!

The CIS intake systems sits entirely above the shroud, except at the gaskets between the intake runners and the heads. Unless someone connected some hoses where they are not supposed to go, I don't know of any other ways for smoke to get under the shroud in that quantity.

I lifted the car and ran the smoke test so I can watch underneath. Here's a link to the video: https://youtu.be/-_uq94os3r8

The first smoke appears at 39 secs. I clearly see smoke streaming in front of the #6 exhaust port - it isn't the port gasket, seems to be coming from a gap in the deflector shield around the cylinder housing. There is. a little from a similar place on #5.


At 1 min 57 sec I cleared the smoke and got a good video of smoke streaming out a slot just ahead of the #6 exhaust port.

I could not tell how much smoke was filling the top side since I was below. I will have my wife watch the top while I watch the bottom to see where the smoke appears first.

I can clearly see the #6 intake runner and its gasket and I didn't see any smoke in that area on previous tests.

I cleared out the smoke and lowered the car and set up my camera to watch intake 6. Don't pay attention to my narrative - I was watching via a mirror and did not see what the camera saw. You can see a tiny wisp of smoke just below and to the right of the copper nut and then it increases and comes from other areas after that.

https://youtu.be/aIPeUUhoQi8

So, I suppose if the gasket is leaking on intake 6, as you say Pete, the smoke would be trapped been the shroud and engine and could stream to the rear to escape - and escape around the cylinder baffle plates like I saw in the underneath video posted before this one.

Now what!?

To me there's way too much smoke underneath the engine...which must not be there...
Make sure to get to know where this is coming from exactly. Following the second video I cannot imagine that this would come from the intake runner #6 only. To me it seems that there's another leak under the fan shroud?!?

Thomas

The best I can tell after multiple smoke tests and videoing and carefully watching above and below the engine bay is that I don’t see the leak so it must be under the shroud and most likely on the right side.

I don’t get discouraged easily and after having my car in a professional shop for 6 months and then working through many big issues and now this vacuum leak that I can’t find, I am at my wits end. The weather is getting too cold to work
In my garage. I just don’t have anymore plans. I cant remove the engine now as it’s too cold and I’m too old.

Un-explitive-believable. I just can't accept failure and not solving a problem so I went back out to the garage, Literally stuffed myself into the engine bay so I could see around to the front side of intake #6 and found this. The first photo is just the setup so you can see what I am doing - mirror and lighting on the front-most nut of intake #6 with a pick tool lifting the washer. The second photo is a close up of the mirror where you can see the tip of the pick under the washer. This bolt wasn't even screwed down! Not even a little.

I don't think I can get to it to tighten it though. I might have to modify a wrench to make a stubby or something. And it likely is not the only one? The shop did not drop the engine to do the airbox replacement so maybe this was hard to get to?

If I have to remove the CIS system it should be a LOT easier since it was just removed and all of the frozen hardware was replaced and anti-sieze used on it.

Thoughts and ideas welcome.

http://forums.pelicanparts.com/uploa...1731270725.jpg
http://forums.pelicanparts.com/uploa...1731270725.jpg

You can do a partial drop of the engine. Search here in the forum on how to do. This seems not to be very helpful to get a few inches more room to work on the CIS but it makes the difference to pull the whole CIS from the engine if necessary.

https://www.pelicanparts.com/techarticles/911_partial_engine_drop/911_partial_engine_drop.htm

https://forums.pelicanparts.com/porsche-911-technical-forum/734835-how-do-you-do-partial-engine-drop.html