R33 Rb25Det Running Rich On Idle

[Dose Pipe Sutututu]

Hi All,

So recently I've connected up an wideband O2 with narrowband simulation (Innovate MTX-L). I'm currently using the narrowband output from the wideband and connected to the factory ECU deleting the existing factory narrowband sensor.

To my surprise, the motor isn't idling at stoich which is strange it averages around 12.7 A/F when warm.

There are no vacuum leaks, no vented catch cans or anything as such, and I believe the coolant temp sensor is working because when it's disconnected the car won't start.

No real biggie, as I will be getting a standalone soon enough, but just curious on why the factory ECU runs so damn rich on idle? On full song at 0.7bar it drops to 10.5 A/F which is expected of a stock ECU.

This is the first time I've put a wideband to analyse A/F on a factory ECU, so I'm curious to see if that's correct? I always thought it should be idling on stoich, and even on light throttle/cruise the A/Fs are averaging at 13.3.

I might try cleaning the AFM this weekend and see if that makes any difference (I highly doubt it).

Any other ideas?

[StevenCJR31]

are you getting these figures when the engine is cold or warm?

[Dose Pipe Sutututu]

are you getting these figures when the engine is cold or warm?

After a nice drive, thermostat is fully opened idle is at 650 rpm, I get about 12.7 A/F. On a cold start up I'm getting about 11.4 A/F. Like mentioned before, I'm not too concerned about it as I will be getting a new ECU soon enough.

Just more of a curious thing.

[Ben C34]

That's not right. like you said should be idle and cruise at stoichiometric

Edited July 25, 2013 by superben

[Missileman]

put my techedge wideband in on the weekend, stock map in my RB20Det, idle @ 72 deg has an afr of 15:1

what location did you mount the sensor and have you tried a free air calibration?

[AngryRB]

After a nice drive, thermostat is fully opened idle is at 650 rpm, I get about 12.7 A/F. On a cold start up I'm getting about 11.4 A/F. Like mentioned before, I'm not too concerned about it as I will be getting a new ECU soon enough.

Just more of a curious thing.

I can remember mine running rich with a stock ecu, used to puff out a little black smoke just reversing but was never a problem.

[mad082]

My guess is that the ecu isn't reading the narrowband output correctly (either the wideband isn't outputting the right voltage, or it isn't wired up properly) so it's just reverting to the standard mapping.

[Dose Pipe Sutututu]

I'll try and disconnect the narrowband simulation to the ECU and see what it does. My original O2 was dead and was disconnected a few days after I bought the car due to idle hunts.

Instead of replacing a stock O2, I decided to for a wideband with narrowband simulation because I'm going to get a full standalone soon enough.

I'll try and recal the O2 too and see what's going on and also borrow my mate's handheld Innovate wideband and see what's going on.

Oh yeah and the sensor is mounted just before the Cat

[Missileman]

checked my afr today from cold and with cold crank enrichment operating it starts around 12.6 : 1

[Missileman]

Just for you Jonnie xxxooo

the wavy green is the o2 doing it thing, the spike is decal fuel cut.

Notice the lag between throttle V+ and RPM and LAFR, well that how long it takes for my Tech Edge to log what my foot is doing

[Dose Pipe Sutututu]

that lag time isn't too bad!

anyways, just something interesting, took my car on the track yesterday and the consumption was hideous!!

84kms per 25L

flat foot down the straight on wakefield and she was 10.1 A/F

On another note, I did an ECU error code check, got error 13 = water temp sensor..

explains why it's overly rich!

[Missileman]

that lag time isn't too bad!

flat foot down the straight on wakefield and she was 10.1 A/F

On another note, I did an ECU error code check, got error 13 = water temp sensor..

explains why it's overly rich!

Had a feeling the temp sensor was reading incorrectly, 10:1 is fairly normal for the top right corner of the stock fuel map. I've started slowly taking fuel out of mine there, and it's still in the 10.xx:1 range. Put my new 440CC EV14 injectors in tomorrow so I expect my economy will be shite for a couple of week while I attempt a home tune.

[Missileman]

Put my new 440CC EV14 injectors in tomorrow so I expect my economy will be shite for a couple of week while I attempt a home tune.

Haha too easy, injectors in rough tune done, made it home ok, beer O'clock time

[Dose Pipe Sutututu]

Haha too easy, injectors in rough tune done, made it home ok, beer O'clock time

lol.. isn't really rocket science right? just as long as you're getting the right A/F you'll be sweet.