Fuel cut/ boost cut on ST185GT4 celica

[tai_180sx]

i did a quick search but couldn't find anything.

i just want to know what sort of protection is on these GT4 celica's? i am just about to start modifying one with a bigger turbo, injectors, front mount and just wanted to know if i'm going to come across any sort of fuel cuts or boost cuts or anything else like that? and how do i get rid of them. i dont' want any kind of cut's, so is there a wire i can just cut that will not allow any fuel or boost cuts?

[Roundy]

With bigger injectors the way u will get around it will be with a Standalone ECU...u can't run bigger injectors on the std computer.

Std ST185 has a fuel cut at 12psi (ish) and it isn't really recommended to go over that with the std headgasket as they have been known to fail.

[tai_180sx]

i realise you can't run bigger injectors with a std cpu....you would have to be some kind of idiot to do that.

12psi fuel cut hey. is there a wire you can cut to get rid of it completely? if not then which fuel cut defender do you use? the map sensor controlled one or the one you wire in?

[Roundy]

well if u go after market ECU you won't need to install an FCD, u can adjust the fuel cut with the ECU (if provided).

I don't have a FCD on my car

Otherwise u can make an FCD fairly easily

http://www.gtfours.co.uk/

u can find how to make on there.

[Jorrs]

hey tai bro good to see the celica comin along

[sw20r]

no need for a wire mate. or fcd.

the turbo vsv near the firewall. pull that hose and stick in a screw to block it off. also block off the vacuum from the intake.

your boost gauge on the dash wont work anymore. this eliminates how much boost it sees thus eliminates the fcd. its a free mod!

[-==L=a=N=c=E==-]

urrrm, that isn't the turbo vsv, its just a normal run of the mill MAP sensor.

the turbo vsv (t-vsv) is a small solenoid on the back of the intake runners which controls the boost levels.


I've done the above mentioned method on my gt4. The only downside is that your stock boost gauge doesn't work from there after. Minor if you ask me as it is useless.

[sw20r]

yeah sorry its a map sensor for the turbo gauge/fcd. i stand corrected hehe

[camrygt?]

This is probably the same as the link above, but if you want to keep your dash boost gauge putting the correct zener diode across the output of the map sensor should clamp the output voltage to a level just below boost cut.
Usually toyotas cut when the map sensor output reaches close to 5 volts so a 4.7 volt or 4.3 volt zener diode (a few cents from dick smiths or jaycar) should allow the senor to work normally until it reaches this voltage then stop it from going any higher.
Be carefull with this as there will be no boost cut at all.

If you wanted to keep the boost cut just move it to a higher value try a ST205 map sensor or possibly a 1JZ map sensor as these have different output curves.

At a guess I would say the 1J sensor reaches about 4.7 volts at around 14-15psi and the 205 sensor around 19 psi or more (the output curves curves for 205 are on the web somewhere)

[tai_180sx]

ok so i can just disconnect whats pictured there?

um sorry guys, i should have mentioned i'm not an idiot. i realise that when i put an aftermarket computer in it will get rid of any cuts....i'm not putting an aftermarket computer in for a fair while yet. i'm trying to get it running for now.
i usually work on nissan's. i've never worked on toyota's before. but now that i have one i'm trying to work out everything i can so get this gt4 going great.
it already has a bigger turbo on it and i'm gonna whack it on the dyno and wind the boost up to see where the injectors max out. then i'll get bigger injectors and either get a full computer or just an air/fuel controller. this car is being done kinda cheaply so it'll probably be the air/fuel controller.

[tai_180sx]

i can't find that map sensor for the fcd to unplug.

here is a pic of the front of my engine bay..

there is also a pic of the back of the engine at what looks like could be it...can anyone verify?

[tai_180sx]

can anyone tell me what coloured wired go into this map sensor?

[1gt48u]

thats your boost pressure sensor

you need to find the vsv attached to th inlet manifold

cheers

[tai_180sx]

i need pics.