issues finding this on suncoast porsche parts site with this PN? 996.605.155.00 ? Am I using the wrong thing ????

 

call them. They will know what it is. Ryan at Suncoast knows, I just got one.

 

I'm in the process of replacing the N75 valve but having trouble getting the Y pipe free. I've undone all the y pipe bolts, disconnected the boost hoses, F-hose, little hose on top of Y-pipe, the electronic connector on the top of the Y pipe and I've loosened the jubilee clips. The Y pipe does not seem to want to come free. I can get the Y pipe to twist a bit but that's all. Have I forgot to loosen something else or are there O rings inside the Y-pipe that are just super sticky. Maybe I'm being to gentle? Just don't want to break anything in the process. Any advice from those who have done this would be greatly appreciated and hopefully I can finish this job after work one of these nights this week. Thanks!

 

if you look above on this thread you see they advise going under the y pipe with a long needle nose pliers once you have it loosened . I did it that way and had a very very hard time getting the hoses all the way on but they have held up fine...so far. Also, you have to be very careful not to pull any of the hoses or wiring loose from the other end.

Don't know why the silly y pipe won't come off easily. It would make several jobs much easier. Let me know if you figure out how to get it off. Good luck

 

For those of you who actually did this work without removing the Y Pipe big props to you, because I don't know how the hell you did it. I had to remove the y pipe. Turns out my problem with getting the Y Pipe free is that I'm a big wuss and am just afraid of hurting anything. The Y pipe popped free with a slightly more aggressive twisting action in conjunction with a tug. It just seems its really well seated in the throttle body which is probably a good thing considering the amount of air flowing through there. I did not leave the Y pipe in place as the OP suggests and I'm not sure why you would. With all the hoses already disconnected from the Y pipe, its much easier to just take it out and set the whole pipe aside and have easy access to the N75 valve.

Anyway, much to my surprise I found that the N75 valve was indeed the likely culprit of my problems. When I took it out, one of the little plastic pipes was cracked almost all the way through at the base. Its hard to see (see pic).

I installed the new N75 valve, buttoned everything back up, plugged in the Durametric and cleared the P1255 over-boost code then took the car out for a test drive. All surging and boost issues under load are gone and the car boosts a solid 1.0 bar and is smooth as silk. Only did about a 30 minute cruise around so definitely need to do a longer drive to ensure the problem is fixed but all indication are that this was the problem.

 

Thanks for update and congratulations on your repair!

 

I used these instructions to replace my N75 today. My symptom was only .4 bar of boost - which came on very suddenly. No codes. After replacing the boost solenoid, all better. I did remove the entire Y pipe which made the job easier.

Thanks for the DIY!

 

Is this valve surely related to both high boost surge and low boost issues ?

 

For all who do not have a fuel cooling thingy installed, its alot easier to get the N 75 out.

 

I notice you're in Germany. I'm assuming you have a ROW spec 996TT? What year? Did your car come without the fuel cooler or did you have it removed? I am debating doing an A/C delete and getting rid of the fuel cooler myself. Thx!

 

Porsche installed the fuel cooler, when it was there to install. Its random if you have it or not. I once askes some porsche guys, even they couldnt tell. Its like" ops we ran out of fuel coolers...well bad luck.."
Anyway you dont need it actually cause it works only if the AC runs and only the fuel that flows back from the engine gets cooled. Its kinda useless cause the AC takes away HP, which u hardly could gainfrom cooling the backflowing fuel.
So if u want to deinstall the AC it has no function at all.

 

So to verify, your car came stock without the cooler then? I would love to get the part number for the metal fuel line that must be different on the cars without the coolers. PET doesn't show it. The cars with fuel coolers have a fuel line that goes from the fuel rail to the cooler and to the fuel tank. The non cooler cars must be different.

 

Yes. It is stock. Cant help with partnumber. Will have a look.

 

I probably found it.
In the PET there are two "Saugleitungen" (translation = sucking fuel line ) listed, but only yours is shown at the picture. So my guess is that the line which is not shown, is the one i got.
It should have this number. 996 573 107 00
No guarantee though.

 

Fantastic! Thank you. I'll try to cross reference it. What model year is your car?