6G Celicas Forums

i have a quiestion regarding my gtfour. When I punch the throttle, the turbo pulls hard untill 5000 RPM and then completly loses power until you let off the throttle a bit,then it will start reving higher.

my only idea's are that the wastegate is not letting enough exhaustout Bcause when when the fuel is being burnt the wastegate is keeping the exhaust and not letting the engine give more power. since when i let off the throttle a bit the exhaust is able to start flowing a little better and therefore letting the engine rev higher.

that is my only idea so if anybody else has had or heard of something like this let me know your ideas on how to fix it!

I want to run this car to its fullest potential

What all have you done to the motor? Any wastegate upgrades? turbo? manifold? fuel?

Sounds like it could be a couple of things:

1. Waste gate is too large

2. boost leak anywhere from the controller to the wastegate

3. Enough fuel isnt getting through the injectors

Id try testing a mechanical boost gauge hooked up with a T fitting right before the wastegate too see if your getting a leak. This will be weird looking at the gauge, when you reach full boost the gauge will drop because the controller has shut it off. Thats what it is spose to do anyway.

If this is happening on stock boost and stock turbo, then you most likely need to replace your sparkplugs, cap, rotor and check your ignition timing, as you are having a missfire.

You have a narrowband/wideband? Sounds like you might be loosing fuel pressure and running lean up top.

This post has been edited by Nartanian: Aug 6, 2010 - 9:29 AM

i am pretty sure its a fuel shortage now. it is pretty much stock and i have a boost gauge and it seems to hold boost. is there any sensors that manage air/fuel mix i could check out? maybe a fuel pump? changed the fuel filter but no difference.

I'm not sure how 3s engines are set-up, but you should check the vacuum lines and make sure there is no gas in there. I wanna say it's the line coming of the throttle body to your afpr. What you could also do is check to see if the the nipple at the throttle body is actually creating vacuum. You can just pull the line while the car is idling to check. I'm guessing your afpr has gone bad or is loosing vacuum somehow.

This post has been edited by Nartanian: Aug 15, 2010 - 11:29 AM

do you mean the fuel pressure regulator?? where is this part located?

Also, your ECU might be pulling timing