car is running bad please help

[jasonlee]

setup: 6 bolt engine, ngkpr7es plugs, stock wires, evo 8 550cc injectors, big 16g turbo, 3" intake, maft and 3" gm maf, 3" exhaust from 02 housing back...... also i have a whalbro pump, but it was in the tank when i got the car so i have no idea what size it is... any way to find out? and aeromotive afpr is in the mail.. should be installed by wednesday

i know i should have a datalogger but i dont really know what to go after, and a buddie of mine has a program on his laptop we plug into the obd2 port to get numbers from...

problem is, i have really no idea what they mean... o2 sensor fluctuates greatly from high .90's to way way lower... timing was in the mid to upper 20's most of the time on hard pulls...

short term fuel trim was something like 17 or 16. something... we are doing more detailed logs this week... i just got the maft

symptoms... the car is a serious dog under 4k rpms after that it pulls sum but not as much as i would expect for +16 or more boost...

under 4k i still see boost... around 10-14 or so pounds but the car stumbles pretty bad, and has noooo power.

please let me know what i should be looking for to get this worked out...

thanks!!

jason

 

[1fastlaser]

sounds like its getting to my fuel before there is boost..like its flooding itself then it comes on...Fuel pressure could be too hight and make the injectors go static....There is alot of things.You got to diagnose the problem..and a data logger is the first step

 

[jasonlee]

well, i got the fuel pressure regulator today, installed.. now its set at 43 psi and the car seems to run better (i.e. smoother) but still no power under boost..

it feels the same from 10 psi to 20 psi.. no extra pulling...

arrrrggg

 

[draxus83]

yeah i am haveing the same problom at @18 psi on stock injectors
" turbo back Thermal exhaust, big 16G turbo, Unorthodox underdrive pully
Buscher upper intercooler pipe, GReddy type-s blow off valve, Extreme manual
boost controller, GReddy turbo timer, K & N filter, Front + rear cross drilled rotors
Strut bar, Holley 255 lph fuel pump, Lowering springs
i seem to be having the same damn problom i have a s-afc but on stock injectors do
you guys think our problom could be to much fuel pressure ??? i no i need biger
injectors with the big 16 just havent go around to it i was thinking like rc
660's??? the only difference in our situations is i get thru the bog and i
stay at 18 with no lost or gain in boost and ideas cause i am out and i am
of my car sitting :thumbdown

 

[jasonlee]

new info on this..

i am not sure if its working correctly or not... but my bov is venting all the time... when its at idle it wistles and is letting out a little bit of air..

when i rev it in nuetral it blows air on my hand the whole time, but more when i let off the gas.

its a 1st gen bov

vented due to gm maft in blow through setup

is it supposed to work like that? or should it be holding pressure until a certain boost level?

the car is around 15 or 17 psi of vacum at idle

 

[1fastlaser]

the valve should be closed at idle.There is a problem somewhere.

Eather you got a intercooler pipe leaking somewhere,or that blow off valve diafram is shot or has the wrong vacuum hose on it