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Hello to all  you TGP owners I just want to say this is a very awesome forum and very helpful. I just recently purchased a RED 1990 TGP with only 59,000 miles on the clock. it has its lil issues but I'm sure you guys can help me with that. I am also a GM fanatic and own a 1987 Buick Grand National, 1994 Impala SS and now my TGP. Well as for my gtp it has a problem when it boost up at high RPMs, it kind off stumbles then gets better then if I floor it causes a pop and my vacuum lines come off the TB . the previous owner said that the turbo might be bad and it might need a rebuild. The blade has a little play but not severe. I also checked the oil return line and it might need to be replaced because it has oily sweat around the hose. THANKS ! Give me some ideas what it might be.

Hey congrats and welcome to the forum! Great cars! First, I notcied you called it a GTP towards the middle of the paragraph; we like to correct that with TGP (Turbo Grand Prix). As for your problems, once your engine hits high, and I mean real high, RPM's, you may experience what's called overboost. Simply put, more boost than your turbo will allow. As for the vaccum lines popping off the throttle body, I have the same thing, and I've found that rigging up some zip ties around the lines and running another zip tie down to the upper intercooler pipe keeps it in place. When the lines pop off, you lose your vaccum and you will here a loud, noticable HISS. This also will cause you to loose your boost. Whenever mine popped off, my check engine light also came on until it was set back in place.

Hopefully this will help you out. Ask as many questions as you need! We have plenty of people here who know what they're doing, and even more who know these cars inside and out!

Krenzy

Welcome!  If you have any problems, be sure to do a little reading for yourself, as the majority of the common problems are covered somewhere within this forum.  Also, be sure to use the SEARCH function.

You should post up some pics of your car! ;)

Nick

Welcome man, and please don't forget pics of the GN!!

As far as your vacuum line issue is concerned, are you saying that the entire 4 plug harness separates from the TB?  I would try removing that harness and get a q-tip with some alcohol or brake cleaner and clean those 4 holes really well , might be a bit oily and causing them to slip.  The factory installed a black clip to fit over those things, kind of a poor design and over the years of heating and cooling it becomes fragile and breaks very easily, so that may very well be missing.  If it is, you're SOL trying to find one, disco from the dealer and rare to find in a j/y. 

The harness however is still available from the dealer, easily replaceable in about an hours time, including running the lines under the plenum and everything.  I actually had a couple laying around, just sold one a month or so ago to a user here.  I replaced mine last year when I changed the injectors.  It fit much tighter than the original part that was in there.  Mine only had 42k on it when I swapped it, and it was dry and brittle. 

Welcome to the forum!!

FYI - Expect to change the crossover pipe if it is original, they are almost assured to fail.  The return line you speak of is also a culprit to smoking at idle and such.  The tend to unravel internally and cause blockage, forcing oil out of the turbo into the exhaust.  Best $20 and half hour you will ever spend.   :icon_cool:

If it's not already chipped, plan on getting one for it so you can have some fun with it, you never know, it might be almost as fun as that GN.   :laugh:

pn# for vacuum block of the TB is 10114903.  Still available from the dealer but I don't know the exact cost.  I have a spare I'd be willing to part with if you decide to replace it.  I would try cleaning it and maybe the entire TB first to see if it might just be oil causing it to pop out.  Otherwise feel free to contact me. 

Good luck!

Ryan

Welcome to the board. ;) Post some pictures of your car if you're able to.

I doubt the vacuum lines have anything wrong with them @ 59K. The throttle body vacuum line clip is probably just missing. Check and see if you have a little clip that covers the vacuum lines on your throttle body like the one in my picture here(kinda hard to see, but it'll give you an idea).
http://i2.photobucket.com/albums/y33/mfewtrail/1990%20TGP/IM002048a.jpg

Thanks fellas sorry for the late response I appreciate every car guy willing to give a helping hand. :icon_razz:
I have been try to narrow down that freakin overboost issue, I think I narrowed it down to the Solinoid or the wastegate. By the way i already got my first kill in my TGP, dumbass ricer said "that thing has a turbo?" I said wanna find out and I blew right past him in his Honda arccord V6! :icon_twisted:

Awesome! Hey none of your pictures show up, by the way...any chance you can fix it?

 :icon_confused: The pictures showed up last night- great pics BTW!  Where did they go? :laugh:

I can see them now! what can you guys see? I can post them again if you want. ;)

yes please :icon_biggrin:

Nothing but red x's..

They worked yesterday for me also. Yahoo = shittiest picture hosting ever. :laugh:

Sign up for a free photobucket and host your pictures there. ;)
http://photobucket.com/

Thanks freakin YAHOOS! There name says it all!
I will keep trying guys.