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Hey gurus. I have a bit of an issue.. 
s1 R33 Gts25t. Stock RB25DET . 
Apparently has :
a hypergear turbo, EBay 50mms external gate with a screamer , boost controller, fuel pressure regulator, 3" exhaust and a big fmic and a forward facing plenum.
Now the issue is it's running really rich and fuel economy is completely stuffed. The bov has been removed and the pipes been routed to the back of the intake manifold. I have changed my Ecu and maf, and it's still the same. 
I can unplug my tps and the car drives and.Runs normal, but if I unplug the maf the car stalls. Also if i squeeze the bov hose closed the car stalls... and honestly I'm lost as to where to look now. 
Any help would be awesome thanks.

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That whole setup is completely f**ked up.

The BOV return line routed to the back of the manifold is actually feeding the idle control valve.  Which is why it stalls if you crimp it.

You can't run a big turbo and altered fuel pressure etc etc against a stock R33 ECU.  It will tell you to go f**k yourself by making you fill up at every servo you pass.  This fits your description of your symptoms pretty well.  See above post.

thats what i was leaning towards haha , but ive not had time to look into the issues any further since i got the car. wheres the idle control meant to connect to? would be able to keep the hypergear turbo and sort out the bov/idle control piping?

The idle air control draws from the turbo inlet, via a combo of rubber and hardpipes that are attached to the original crossover inlet pipe arrangement.  The butchered plenum means that all that is gone, so the butcher found a way.  The BOV returns to the same place (turbo inlet, a separate port), so it's not incorrect for it to be hooked up the way that it is, just an ugly hack.

If you want a BOV back, you will need to attach it to the cold side intercooler pipe just before the TB and return it to the turbo inlet.  This is not strictly necessary - just depends on whether you like dose or like to have the inlet air bypass the turbo when on cruise (which is what it is actually for).

The main issue is the ECU.

54 minutes ago, Wrighty said:

thanks for help everyone, im thinking ill have to get a new ecu. but i still dont know why the car runs without the tps

Because the tps isn't a very important sensor for how 99. 9% of cars run

Original owner has wasted money on a FFP and a fuel regulator when what he NEEDED was bigger injectors and a tunable ecu...either a Link, adaptronic etc or for less money and a little investigation a Nistune set up.

  • 1 month later...
  • 7 months later...

fixed the IACV hose that was butchered by previous owner, also have worked out it just needs an ecu and a tune to sort the other issues out, has new coils and plugs now as well

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