ECU Pin-Out Complete for VR4

[Kaldek]

I'm installing my AEM Wideband AFR meter and I have a white and a brown wire for analog output (diagram attached.) Does anybody know what two wires these go to on the ECU?

OK, short question but it has a long answer.

If you have removed your narrowband sensor and have screwed the wideband in to where it was mounted, your ability to connect the new sensor will depend on what your AEM can do.

I have only used the Innovate LC-1 and LC-2 sensor kits. Those both have a "simulated narrowband" output which can be used to connect to the narrowband signal input wire to the ECU. It's a white wire, pin 6 on connector C39. IGNORE THE FACT THAT THE INCLUDED DIAGRAM HAS PIN 5 FOR WIDEBAND. That's a scenario which is only useful for data logging (and may need a custom ROM), not possible for tuning. Again, ignore it.

The 5v outputs on your AEM look like wideband signals for connection to an ECU or datalogger, but the Legnum ECU only accepts a narrowband input. So, in your case you can't use the AEM for narrowband simulation.

You can leave it disconnected and the car should still run fairly OK, but you can also have the ROM edited using ECUFlash to disable closed loop mode. My built, tuned, E85 flex fuel ROM has it disabled.

 

[BCX]

Agree with the above.

Your options are:
1. Do nothing. You're fuel trims will be out of wack and eventually might get a CEL. Input into rear o2 input you would like to log.

2. Edit rom, disable close loop. Feed into either front or rear o2 input for logging purposes if required

3. Use a rom that has wideband to narrow band scaling. I can provide a rom. If your current rom is tuned, then you'll need to copy all tables over. Feed into front o2 input.

4. Aftermarket ecu, use canbus instead.



Same as @Kaldek, mine also has close loop disabled even with the wideband to narrow band function in my rom.

 

[6A13TT TYPE S]

Agree with the above.

Your options are:
1. Do nothing. You're fuel trims will be out of wack and eventually might get a CEL. Input into rear o2 input you would like to log.

2. Edit rom, disable close loop. Feed into either front or rear o2 input for logging purposes if required

3. Use a rom that has wideband to narrow band scaling. I can provide a rom. If your current rom is tuned, then you'll need to copy all tables over. Feed into front o2 input.

4. Aftermarket ecu, use canbus instead.



Same as @Kaldek, mine also has close loop disabled even with the wideband to narrow band function in my rom.

Can confirm fuel trims are bugger all and dont make a noticeable difference as I have had cars with external wideband loggers withh the OE sensor disconnected and no simulation into the stock ecu. And it does not trigger a CEL

That being said for what purpose are you installing this wideband? Because without an aftermarket ROM or aftermarket ecu you won't see any benefits from it.

If just for a tuning tool, cool to that then put the narrowband back in if you want the ecu to have a signal

If for the gauge and readout because you want it, fair enough but you can also weld a 2nd bung in and run wideband for the gauge and stock narrowband for the ecu.

Or you can see if there's a 0-5 to 0-1 wide band to narrow band converter available to do what the old LC-1s used to do

 

[mezje]

Can confirm fuel trims are bugger all and dont make a noticeable difference as I have had cars with external wideband loggers withh the OE sensor disconnected and no simulation into the stock ecu. And it does not trigger a CEL

That being said for what purpose are you installing this wideband? Because without an aftermarket ROM or aftermarket ecu you won't see any benefits from it.

If just for a tuning tool, cool to that then put the narrowband back in if you want the ecu to have a signal

If for the gauge and readout because you want it, fair enough but you can also weld a 2nd bung in and run wideband for the gauge and stock narrowband for the ecu.

Or you can see if there's a 0-5 to 0-1 wide band to narrow band converter available to do what the old LC-1s used to do

If it's just for monitoring purposes bung is definitely the way to go

 

[Kaldek]

3. Use a rom that has wideband to narrow band scaling. I can provide a rom. If your current rom is tuned, then you'll need to copy all tables over. Feed into front o2 input.

Bill what's the risk of doing this considering the "reliability" of wideband sensors? I blew through a heap of LSU 4.9s (sure, a few were fakes but even the OEMs don't last) and reverted back to the LSU 4.2. Whilst it's not died, it occasionally cracks the shits, reads full lean, and needs a power cycle to get it to report. It's only once in a blue moon, but still...

 

[Kaldek]

This is is also an excellent article about the LSU 4.9 sensors. Read it before you start killing them:

Why Bosch LSU wide-band air/fuel ratio (or Lambda) sensors fail so often in aftermarket performance applications - NZEFI

Bosch is the world's leading manufacturer of exhaust gas oxygen sensors. Their LSU range of wide-band sensors has been widely adopted by the OEMs and can be found on a huge number of production vehicles to accurately measure Lambda or the air/fuel ratio (AFR) in the exhaust system. Their common...

www.nzefi.com

 

[BCX]

Oh yeah, been through a few LSU4.9 sensors. They are rubbish. Last 4.9 sensor died when it was on the dyno. I really wanted the aem uego kit, but ended up with another innovate just to have the functionality of going back to a 4.2 sensor.

I wired my sensor to power when fuel pump is running to overcome the thermal shock. Most wire to ignition cos its a bit easier, but its easy to accidentally leave the ign on and delay starting when its cold.

My latest 4.9 sensor seems to have lasted a bit longer... But going back to a 4.2 after this one dies. And cant quite justify an NTK sensor cost wise.

Im not interested in accuracy, i just want to know when im deviating from baseline 'good'.

 

[Kaldek]

Oh yeah, been through a few LSU4.9 sensors. They are rubbish. Last 4.9 sensor died when it was on the dyno. I really wanted the aem uego kit, but ended up with another innovate just to have the functionality of going back to a 4.2 sensor.

I wired my sensor to power when fuel pump is running to overcome the thermal shock. Most wire to ignition cos its a bit easier, but its easy to accidentally leave the ign on and delay starting when its cold.

My latest 4.9 sensor seems to have lasted a bit longer... But going back to a 4.2 after this one dies. And cant quite justify an NTK sensor cost wise.

Im not interested in accuracy, i just want to know when im deviating from baseline 'good'.

Same same. Kept the LC-2 and just bought the harness for LSU 4.2. I even had my LSU 4.9 power up controlled by the UTCOMP and based on engine temperature coming up a little. I still burned through sensors.

As for the accuracy, agreed - it wasn't for tuning it's mainly for deviation and alarms (although the UTCOMP can't alarm based on load vs. AFR or anything close).

The NTK sensors must have come down; Haltech has them for a couple hundred bucks with modifications for longevity. Of course, you need the ECU or the Widweband controller ($699 for the controller + sensor). Still not actually that bad I suppose; I've easily spent that much on sensors.

 

[Spetz]

Does anyone know if the ECU has a direct line to the CEL?
My CEL is not lighting up on startup.
Checked the bulb and cluster and everything is OK.
I traced the instrument cluster pin for the CEL and did a continuity test on the ECU pins and none had continuity.
I assumed that there should be a direct link between the 2

 

[Kaldek]

Yes, it does. You won't see continuity because it will be switched by a transistor. Connect a multimeter to the CEL pin (there's only one) and a ground, and turn the ignition on. You should see 12 volts briefly.

The pin number and wire color is here a few posts back with the full ECU pinout.

 

[BCX]

Behaviour will be the opposite if you probe at ecu.

12v always on one side of cel, then ecu switches the earth.

So at start up, youll see 0.5-0.6v (voltage drop over the transistor) for a few seconds then 12v when the transistor turns off.

 

[Kaldek]

Behaviour will be the opposite if you probe at ecu.

12v always on one side of cel, then ecu switches the earth.

So at start up, youll see 0.5-0.6v (voltage drop over the transistor) for a few seconds then 12v when the transistor turns off.

Thanks Bill. Of course it's earth switched!