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Hey guys, first post on this forum. I have recently bought a new car. An 1994 r33 gts-t,which has a RB25de neo in it (n/a as im still on my p's) im having and issue with it idling (plan on cleaning the aic this weekend/during the week) and it is running rich and very poor fuel economy. I believe it may still have the r33 gtst ecu (ecu has blue label on it) I would like to know if it is possible that the ecu is the problem, i have clean the afm, done plugs and changed the coilpacks to splitfires. thanks and i look forward to being involved with this community :D

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Wait, so it's a GTS-T and someone's pulled out the RB25det and put in an RB25de?

If so, you may as well have bought one with a turbo. You're driving a car you're not meant to, regardless of engine. Removing the turbo doesn't make it P plate friendly.

As for your problem, I'd start by sourcing a non-turbo ecu for it.

Cowboy1600, i dont know what you mean, not p plate friendly. Its a gtst... Yes... Which now has a completely different motor in it, rb25de neo from an r34 making it n/a. Which means by law it is 'p plate friendly'. In regards to dtc 54 i dont understand why its throwing that unless it also has had a manual conversion that im unknown of and they havent changed the ecu there either.

Welcome to SAU Blake!

Technically the guys are right about driving a GTST minus the T. Keep your head down, don't be too silly & you should be right (unless you get a copper who know how to read a compliance plate).

Running a GTST ECU on a NEO N/A is not the best idea.

What were the plugs like when you pulled them out?

There could be a few things going on here. Yes the ECU could be at fault. You could also have an intake leak somewhere or even an exhaust leak before the O2 sensor causing it to fuel up a bit, but seeings as its thrown a code for the O2 sensor, I'd start there & double check everything else to be safe.

Researching the part # on the ECU would be a good thing too.

update to this. Replaced the o2 sensor today, seems to be running not as rich. looked up the ecu last night, found out it has correct ecu for engine. I am now chasing a vacuum leak in the engine which i will sort when i clean the aic this weekend :D

Edited by Bwillie

seems like gapping spark plugs to 0.8mm, setting the idle properly, checking the timing, set to 30 degrees (woohoo) and running 98 octane shell v power is making it run much smoother and MORE POWER! Cleaned aic etc, didnt seem to be that dirty compared to others ive seen!

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