OK thanks guys for the help! There are many choices out there. Looks like I can pickup the 710's for $120 and an good aftermarket silicone f hose for $75. That saves me at least $180 on alternative DV's!

After seeing the stock f hose I would definately not want to buy a stock unit!

 

After replacing the F hose and new diverters with Bosch 710's everything seems sealed up, no air noise or bubbles with soapy water. 18 psi is as high as I took it, the split F hose seems to have been the only problem.

The old diverters looked brand new (30K miles on mostly garage queen), but just replaced as precautionary, it is a bit of work to tear it all apart again!

Anyway, I ended up cutting the f hose out with a knife, still couldn't get to the hose clamp on the far diverter valve because the clip was to the front of the car.

Sears makes a nice cable operated hose clamp removal tool for $40. After a hour or two trying to figure out how to get pliers in position, the new tool had the clamp off in 2 minutes!

 

Nice good work....

 

Pic?

 

Astro Pneumatic 9409A Hose Clamp Pliers https://www.amazon.com/dp/B003D3N7YW..._pg9sub1JQGCAB

 

Cool!
Looks like my stocking stuffer item for Christmas.

 

Not to mention we wre dealing with 10 year old plus cars. Vac lines do expand and fail.

 

Bot.

 

I'm using the tester from 911tuning, IT works amazing--I wanted to make one, but I wanted high quality stuff not plastic tester...made from home depot.

btw i do boost leak test every 4k miles when I do oil change. 996's getting older
you never know which hose can pop open.

 

Boost is coming on lazy - which means it's hi time for a boost leak test.

Sure enough, she's not holding pressure and I can hear a good size leak coming from just under and left of where the Y-intake merge pipe meets the throttle body.

Anyone have a diagram or pic of what down there that likes to leak?

 

Sounds like a throttle body o ring. But it can be anything as pressure has a way of fooling us. It also can be any of the 3 vacuum lines to the left of the tb that's connected to the intake behind the tb.
Markski

 

Thanks for the response. I changed the TB o-ring about 5k miles ago so hopefully it's not that.

I do suspect its one of the smaller vac lines that runs to a splitter under the TB that's blown itself off. I'll have to get into there anyways to resolve it so I'll figure it out soon enough. Just wondering if it might be a common part failure down there, or I'll just make sure to zip tie things up once I get things re-fitted back.

This car sure is pesky with the pressure side of things. I've fixed no less than 4 different issues related to vac leaks/check valves in the last year alone and my car has only 37k miles. Guess it's what happens when you have a hot wife and hot car, each one vying for attention.

 

that could also be a cracked check valve past the y pipe on top of the plenum. they crack and there goes proper boost. the pressure test at the turbo would find that immediately. it was a loud hiss, and i had the new valve in hand. replaced all thee incl the n75 they're cheap do it, probably thats it. ( maybe lol ). since replacing i hold steady ( again lol ) at 1.2 spikes to .3.

good luck

 

Found the culprit! Tiny little sense vacuum line.

Anyone know what this circuit does? Little hose that's unconnected, directly left of the TB bottom left brass nut.




EDIT: quick google shows that it's the FPR boost reference line.

 

thats the vent return line from the FPR if I see the pic correctly...