Trouble with building boost at launch

[UCIGN]

Hi guys,
I have an 86 GN ,slightly above stock turbo from the 90's,rebuilt tranny with stock converter,42lb inj,FPR,voltage booster,hot wire,fuel pump,TT chip,snow alc system,stock suspension,running BFG 255/60/15 Comp TA's ,I have slicks,but haven't needed them.My problem is I litteraly have my brakes on and my foot to the floor,max boost I get is 5lbs,no creep and no tires letting loose,needless to say this is not conducive to a good 60'(2.2),it will build boost once i let go ,up to 21.5lbs,any ideas would be great,

 

[T- Type Tim]

How about a leaking pcv valve .....boost into crank case? Found mine leaking horribly. Also a cracked header betwwen 3 and 5.

 

[Chuck Leeper]

Start with what Tim mentioned, then...
Tune could be a problem. Do some data logs, and take a look.
I'd not expect too much from that converter.
What is the turbo? [Too much for the converter?]
Exhaust system is?
Is it really 5psi?? How are you getting that #? What gauges do you have?
What's the fuel psi doing?
Far too many unanswered ??'s, to draw any conclusions. Some logs would be a start....Along with a really GOOD "physical" of the entire car.

 

[SHADOWII]

If eveything forward of the flexplate is proved normal, You have trans/converter problems.

 

[KEVINS]

What wastegate actuator is on the car?
Are you flooring it to build boost?
In order for me to build boost I only opened it maybe 1/4 throttle and hold it there and let it build boost. Once it started I would slowly open it a little more but never near 1/2 way. Once it starts to build boost it will continue to build it on its own then when it hit 15psi I let her rip..

ks

 

[UCIGN]

Stock waste gate,if I had a cracked header wouldn't it be quite noisy?how can I check PCV valve leak or just replace it?I just bought a data logger haven't had a chance to install yet,I'm using an auto meter gauge and the snow gauge also has boost,the torque converter was just rebuilt by TCS ,can't read the fp when driving the gauge is under the hood ,but is set to 43lbs hose off and plugged.With the PCV valve can we pick that up anywhere or is that specific for GNs and hard to find?The turbo is an ATR I think it's an HP142,all I could find on that is it basically a step above stock ,I believe it's between stock and 44.any help would be great,again thanks guys.

 

[kidglok]

what rpm are you at 5psi?

 

[UCIGN]

Can't tell ,only have factory led gauge,no data logger yet,but it's not high as the engine isn't screaming.

 

[Chuck Leeper]

First things first, then.... Install the logger, then do the diagnosis, using valid info.......

 

[SHADOWII]

Stock waste gate,if I had a cracked header wouldn't it be quite noisy?how can I check PCV valve leak or just replace it?

The pcv is still available in the auto parts stores. Suprisingly, a cracked header does not make a lot of noise. you might hear a buzzzzz when driving w/the window down and it sounds more like something is loose. Under boost there seems to be enough noise(loud mufflers, etc.) going on not to hear the exh. blowing out. A short crack can get you upto 9 or 10#s of boost and have you chasing your tail trying to locate the problem.
Have you checked the turbo wheel for free spinning? Coked bearings can put a hurt on your boost.

 

[UCIGN]

I will install power logger this week, ordered a PCV valve already , I will put that in,and get back to you guys when I have more info, only thing is I don't have a wide band yet or Aux map sensor, do I require these for the power logger to work or are they for fuel ratio etc, not sure what the aux map sensor is for though(is that a factory peice or after market)

Thanks for the advice.