Help Please, Rb25De Neo Issue.

[Bwillie]

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

[Ben C34]

The different ecu can't be helping.

Check the ecu for error codes.

[Bwillie]

Yeh ive been meaning to get that done, i would like to know if i took a picture of the ecu if someone could identify it as a turbo ecu OR the n/a neo one.

[Bwillie]

Just did the short two pins on the obd plug. Got 54 and 33. O.o.... I shall looks these up and find out what it all means

[Cowboy1600]

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.

[Ben C34]

That's trans and o2 sensor.

I agree with above post,

[Bwillie]

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.

[533 RYC]

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.

[Josh080691]

As above engine conversion from a. 34 to a 33 is a defect on its own and still makes it illegal to drive on p's.

[Bwillie]

Yeh i tried looking up the ecu number, i couldnt find anything and the plugs werent terrible abit of carbon on the end (indicating rich)

[StevenCJR31]

The ecu number on on a sticker on the side of the ecu

[Bwillie]

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

Edited February 20, 2014 by Bwillie

[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!

[Ben C34]

30 degrees? Turbos run 15, is the non turbo that different? Whatever, if you think it's running good go with it! so long as you know what detonation sounds like

[jiffo]

25de Neo is 15 degrees BTDC.

Neo engine has a totally different ecu plug to the 33's Rb25, no way you could confuse them.