Hi all, recently I had a problem with my 92 GTO when the seal between the y pipe and the throttle body cracked and was sucked into it causing my throttle to stick. Ok to fix this I installed a silicon seal over both parts rather than one inside. All good I think.

At the same time I asked on this forum where the tube went to from the outlet on the upper end and side of the y pipe (the small vacuum line). I was told it went to the wastegate actuators for the turbos. Now mind you it hasn't been connected to these for over a year and I haven't had any problems. But someone said I could damage the turbos if it wasn't connected. So I have teed into these lines to supply vaccum....

I took the car out for the first time the other day (not my daily ride) and at low revs didn't notice anything but when accelerating there seems to be very little boost. Has anyone got any ideas? Something is just not right and now I'm thinking I should have just stuck with fixing the original problem and left the rest.

ANy help would appreciated?????
:unsure:

Another thought....I checked today for what hoses went where. There is a vacuum hose which comes from the manifold after the throttle body which feeds the wastegate actuators. On advice I had fitted a tee into the same line from the inlet side of the y pipe...this doesn't seem to make sense. Perhaps mine is piped up differently than the workshop diagram? Would vacuum from either side of the throttle body make any difference and for that matter, cause any problems? Worst still would this have caused any damage to the turbos?

I'm at a loss to what is going on at present....

can you use ms paint and draw a diagram with how you have everything hooked up

include turbos
intake mani
ect

I will but have to go away from home for a few days so will do it when I get back. :liebe011:

Have taken a photo and labelled...does this help?

You sure your not leaking at the ypipe-throttle body connection.

Get a boost gauge and be sure.

Hi, thanks for everyone's input. It indeed turned out to be joint between the y pipe and the throttle body. As the old seal died I have tried using a 3" - 2 1/2" silicone rubber reducer to fix this. The problem is that while the smaller end clamps over the throttle body ok the end over the y pipe keeps blowing off. The plastic y pipe won't accept any tension through the pipe clamp.

I have just tried using a silicone adhesive to glue the two parts together but it only lasted a day (and that was without any signiifcant boost running through it). Has anyone got any ideas on a glue that won't let go or any other suitable alternative?

cheers

You have to get the coupler to go over the hump on the outside of the y-pipe and then clamp it down. I usually use a 3 inch silicon hose coupler (reinforced).

Also, the T fitting used for your wastegate actuators looks to be broken. There should be 4 fittings on there... not just 3. 2 for the wastegate actuators, one for the hose coming off the y-pipe, and one going to the boost control solenoid. The other port on the boost control solenoid should go to the rear turbo's intake pipe.

You have your vacuum lines wrong in many places. Please redo them the right way. This is definitely a big problem.