i have a 99 GST spyder, i have upgraded the radiator, intercooler, piping, BOF, intake, clutch, flywheel, fuel pump, fuel lines, fuel rail, cat back exhaust, wires, spark plugs, shifter, turbo timer, Turbo.... might be more...

BUT I AM HAVING A PROBLEM.....

when i slam the throttle, the lower RPM's are good but when i hit about 4k it starts hickupping and i need to let off the throttle for it to smooth out and accelerate correctly...

at first i thought it wasnt enough fuel, so i got a high psi fuel pump and larger fuel lines, then i got an AEM fuel rail...

wasn't that...

then i tried the clutch thinking it just couldn't handle the power...

wasnt that...

tried intake...

tried plugs...

tried a new intercooler and piping...

GOSH DANG IT@!!@!@

i am runing a stock computer with a turbo timer... i just don't know where to go from here...

 

get a SAFC try to c if that will fix the problem it might be your wastegate 2. or just take your car to a professional tuning shop and have them take a look at it.

 

getting an safc is a terrible solution, its not going to fix whatever it is. it can only be fuel, spark, or intake leak. does it only do it under hard acceleration?if its a spudder/quiet popping sound and it doesnt accelerate well its probably an intake leak, your engine isnt getting enough air and its drowning in fuel. check all hoses. try accelerating very slowly and see if it still does it without boosting at all. if it still does then its probably spark. intake leak would only do it under heavy acceleration, spark would be rpm related, in which case you could replace the wires

 

only happens when i slam the throttle.... if i accelerate slowly its fine.... i can hold the peddle 3/4 down and no problem. when i hold the throttle, and that turbo spools, it hickups/ jerks kinda hard...

 

what is a SAFC, heard of it, never got into lookin at it, how would it benefit me.

 

i think you need to check al intake hoses, sounds like a boost leak. if yoiu have replaced the intake, intercooler, turbo etc, almost for sure there is a small leak somewhere

safc controls air/fuel ratio, you can trick your ecu into seeing less air going into the engine, so it will dump less fuel. thats a dumb solution, because assuming your problem is an intake leak, if you first use the safc to remove fuel from engine, the later when you fix the intake leak your engine wont have enough fuel for the air coming in and you will blow the motor. safc is a tuning tool, not a repair tool.

 

same thing is happening to me, my mechanic said it sounds like a vacuum leak somewhere. so try checking your lines, thats what im doing,

 

not a vcacuum problem...

 

ok had a friend look and drive the car, he came with lol a FEW things...

could be my greddy blow off valve... not holding boost, there is a whistle coming from somewhere when i let off the gas, not a normal blow off valve sound...

pressure leak somewhere...

my injectors still being stock....

he thinks the biggest problem is that i have done all this work and not ever had it tuned...
he feels an ecu flash or engine management could solve the problem...

he said it may be detonation.... since the ecu hasnt been worked with... may be problem with timing...


more ideas please guys...

 

try some and eliminate.