87 GN WOT problems

[LS1EATR]

I am trying to help my friend with his 87 GN , heres the a quick run down Stock Turbo , 50#inj, custom chip , changed neck on the cooler, and ScanMaster. The problem it is having is as follows, if you drive the car normally it will act fine , but if you stomp the gas pedal, the car will run horrible and make only 15psi. According to him the scanmaster numbers are good. The fuel pressure is at 38 (no vac) , I checked it under boost ( power breaking) and with 4psi of boost the pressure jumped to areound 41. it has almost all new sensors on it (he has changed them all) i think all he has left is the crank or cam sensor. Also he changed the injectors back to stock , with a stock style chip and the car acted the same way. I am open to suggestions... I can provide scanmaster numbers if needed.... (i have to get them from him) I am a Mustang guy but have always liked the GN's so hopefully we can all get along haha... thanks in advance

 

[sweetv6]

Hi !

check for a craked headers driver side

check for valve spring

and this site

http://209.120.158.83/

hope it help

Claude

 

[LS1EATR]

By the way , it has no engine codes , car really acts like it is not getting fuel , or the bypass is dumping off boost. I have a wideband o2 , but i need to weld the bung in his exhaust , so hopefully that will give us an idea.

 

[LS1EATR]

Valve springs are new.