Standard Ecu Or?

[Coxie]

I've got a s2 r33 with the following mods...

full exhaust, cooler, intake, turbo upgrade & external wastegate, splitfires.

Asked for an 8psi spring for the wastegate but when i installed everything, found out it was an 11psi spring so now running 11psi.

It runs fine, a bit rich as expected, but what I was wondering about is I haven't come across a boost/fuel cut and there is no speed cut either. I wound the boost up to slightly over 15 psi temporarily with a boost controller just to check if there was any boost or fuel cut but nothing?

I've examined the ECU and it appears to be the stanard one but why is it not limiting the boost or anything? And I thought the standard ecu's could not be remapped?

[2LV8ETR]

ECU's can be chipped to remove the boost cutout, speed limiter, rev limiter, etc.

The best way to tell is to open it up and see if the original EPROM exists.

[Coxie]

Ok thanks, once I get the ecu cover off, what am I looking for to tell if it's all original or not...? or will it be obvious?

[2LV8ETR]

There could be an aftermarket EPROM, or someone could have flashed the existing one.

To know if it's aftermarket, remove the ECU and the cover.

Be careful here as the PCB's are static sensitive.

Once you get the cover off, there will another PCB over the top of the main board.

You'll see this:

See where the big blob of brown is on the lower LHS corner? That's the EPROM. This is a Mines ECU so they have placed a tamperproof resin over the EPROM.

The stock EPROM will have a silver label over it with a typical #####-##### Nissan part number on it.

[Coxie]

What model skyline is that ecu from? looks different to mine (r33 s2). Heres a pic of my ecu, nothing I can see that looks tampered with

[mad082]

There could be an aftermarket EPROM, or someone could have flashed the existing one.

To know if it's aftermarket, remove the ECU and the cover.

Be careful here as the PCB's are static sensitive.

Once you get the cover off, there will another PCB over the top of the main board.

You'll see this:

See where the big blob of brown is on the lower LHS corner? That's the EPROM. This is a Mines ECU so they have placed a tamperproof resin over the EPROM.

The stock EPROM will have a silver label over it with a typical #####-##### Nissan part number on it.

mine looked different to that when it was remapped. it was like coxie's but the top big black square chip with the white line around it was sitting in a little chip holder that went all the way out to the white line

coxie your ecu "appears" to be stock. how did you know there was no speed cut? the stock speedo will usually be reading well past 180kmh (usually about where you would expect 200kmh to be) before it actually cuts out due to speedo error. and how big is your turbo, and how hard did you push it at 15psi? if you wound it up gently it may still cope with 15psi and not cut out. if you floored it and it didn't cut out then that is rather interesting.....

[2LV8ETR]

Sorry man, I was showing the R32 ECU.

The R33 ECU EPROM is the dude on the top left. It is stock. If it was chipped it would have a different label over the photosensitive port like this one.

It may have been flashed. Sorry man, I can't help any more visually.

[Guilt-Toy]

one is a R32 ecu and the other is a R33 ecu.

[Coxie]

2LV8ETR - Yeah it appeared pretty stock looking to me, thanks for the help anyways.

mad082 - Maybe there is a speedcut... I just know it can go a fair bit past the 180k where the speedo dial stops, what speed is the standard speed cut usually at? I just remembered that ages ago when I was still using the stock turbo, I had a burst wastegate vaccum line and the engine overboosted to over 20 psi, without a boost cut coming into play and it was under load when this happened so it seems pretty certain that no boost cut exists... On the plug on my ECU there is evidence of wires that have been cut and joined or tapped into in it's previous life in japan (car had some gps navigation gear left in it) but I can't see what would eliminate the factory boost cut

[Coxie]

Anybody know where I can find a diagram of the ECU wires to tell me what wire is what so I can tell whats been tampered with?

[2LV8ETR]

Here's a link:

RB25DET Pinout

[2LV8ETR]

What speed is the standard speed cut usually at?

180km/h

[Coxie]

On the wiring just back from the ECU plug was a heap of black plastic and insulation tape so i pulled it off and uncovered this plug... Look familier to anyone?

[JonnoHR31]

someone could have cut the speed wire from the speedo to the ecu, this would get rid of the speed cut. from memory its a yellow wire with a black trace

[Coxie]

Ok so i put the ecu back in and now the car doesn't want to start...

It threw a code 12 (air flow meter) because one of the wires that was previously joined on the ecu came apart when i took it out but i connected it back together (it was the air flow meter sensor wire). I reset the ecu and now it's throwing a code 55 meaning eveything should be good, but the car wont start. As soon as i turn the ignition on it starts flashing the code 55? So i'm lost as to whats wrong...

Edited June 11, 2009 by Coxie

[mad082]

Sorry man, I was showing the R32 ECU.

The R33 ECU EPROM is the dude on the top left. It is stock. If it was chipped it would have a different label over the photosensitive port like this one.

It may have been flashed. Sorry man, I can't help any more visually.

yeah that is what mine was like. you can see the eprom holder takes up the space the between the chip and the white line when you compare the 2 pics.

180km/h

but the speedo will usually be reading past 180. both my 180sx and my 33 hit it on the dyno but the speed was reading about 10-20kmh past it (well the speedo only went to 180 but the gap was equivalant to 10 to 20kmh)

[mad082]

you still in diagnostic mode?

[Coxie]

yea doesn't seem to want to get out of diagnostic mode? starts flashing code 55 as soon as I turn on the ignition

[mad082]

have you turned the screw back to the normal position before you turn the ignition off?

i haven't even used the screw on the side of the ecu for diagnostics so not sure how it works. i use a consult cable plugged into the laptop.

[Coxie]

I don't use the screw i just short out the 2 connectors on the plug under the dash on the drivers side