Rb25det Running , Limp?

[tarmac]

yo. been lurkin around here for a while but never signed up

anyway, ive got a r33 gts25t and just upgraded the stock turbo to a hiflowed version.

added a 500hp fuel pump, and basically the car runs like shit.

it goes faster at half throttle than full, or more like the same speed but feels like its being held back bigtime.

i replaced the fuel filter not so long ago.

the engine idles at 500rpm and will always stall if i dont try keep it running.. there are no air leaks.

if i keep my foot down fully it will evenly start popping out the intake i believe and sometimes back fires.

before doing the turbo and fuelpump i had snapped 6 exhaust studs so it wasnt really boosting anyway as there were massive leaks, but before these leaks i ran mint.

i know the o2 sensor wiring is stuffed, but the ecu doesnt use the o2 sensor on boost anyway.

Any ideas??

thanks

[stylin86]

hey mate if you still running the standard ecu and its hasnt had a remap that could be your problem because they have a boost cut at around 14psi and it will sorta of just lose all power? also if you have an aftermarket bov venting to the atmosphere the afm tend to go a bit crazy and your car will stall an backfire a bit? I would recomend getting your ecu retuned and having the boost cut removed. Thats only my opinion but i had similar troubles an once i installed a re-tuned r33 ecu the backfiring dissapeared an also the stalling e.t.c good luck with it.

[tarmac]

yeh i do abit of ecu retuning myself and i know that its not the ecu thats playing up. its only running 9psi, and at half throttle psi it goes well, but at full throttle 9psi it goes the same but feels like its bein held back. i should probly check fuel pressure, but i dont know the best way to go about this? is there any homemade sorta rig i can use to check it?

[paulr33]

how have you been doing the tuning? it sounds like you are hitting the rich and retard mapping on the stock ecu, which is based on airflow not boost pressure. what ecu are u using

[James_03]

It wont be boost cut as he is having issues with idle.

First thing I would is switch the ECU over to diagnosis and check for any error codes, the ecu will tell you exactly what has failed if anything.

What condition is the rubber gasket in between the top and bottom half of the plennum? Any raise in boost can often bring gaskets prone to leaking out of the woodwork.

Also check the air re-circulation valve.

It sounds like an air leak but again Im only speculating.