Possible Knock

[89CAL]

If the AFR's sat at 15.5:1 at cruise, then assuming you have a power FC, it wont be a failed O2 sensor. Mine wouldnt sit on 15.5 with O2 feedback on as its not in the range for the standard O2 sensor so the AFR's fluctuate between your desired AFR and say 14.3:1 (or at least mine did)

This is under the assumption that you have a Power FC and are using the standard O2 sensor with O2 feedback on.

Does it feel any different to drive at all?

If not is it possible the wideband is on the way out?

double check all your hoses. I had my AFR's change randomly (one day they were fine then a week later they were to lean, then tune to suit, then they go rich all of a sudden) and I'm pretty sure it was due to one of my breather hoses having a big split in it and sucking in extra air the AFM wasnt seeing

This is on the suction side so made it lean, if you were to lose air on the other side it would make it a bit rich

[Hanaldo]

If the AFR's sat at 15.5:1 at cruise, then assuming you have a power FC, it wont be a failed O2 sensor. Mine wouldnt sit on 15.5 with O2 feedback on as its not in the range for the standard O2 sensor so the AFR's fluctuate between your desired AFR and say 14.3:1 (or at least mine did)

This is under the assumption that you have a Power FC and are using the standard O2 sensor with O2 feedback on.

Does it feel any different to drive at all?

If not is it possible the wideband is on the way out?

double check all your hoses. I had my AFR's change randomly (one day they were fine then a week later they were to lean, then tune to suit, then they go rich all of a sudden) and I'm pretty sure it was due to one of my breather hoses having a big split in it and sucking in extra air the AFM wasnt seeing

This is on the suction side so made it lean, if you were to lose air on the other side it would make it a bit rich

Assumption is off NIStune with no narrowband O2 or feedback.

It doesn't feel any different at all, it feels fine. I was driving on the freeway for almost 2 hours, I didn't feel anything change. At the start of the trip things were fine, by the time I got home my wideband was saying I was running stupidly rich.

[89CAL]

Assumption is off NIStune with no narrowband O2 or feedback.

It doesn't feel any different at all, it feels fine. I was driving on the freeway for almost 2 hours, I didn't feel anything change. At the start of the trip things were fine, by the time I got home my wideband was saying I was running stupidly rich.

Haha whoops

O.K so all the cruise AFR's were tuned manually?

Sounds like something on the pressure side is getting hot and letting some of the air out possibly? but I guess you'd hear that on boost if it had an air leak.......

Short of saying try another AFM or CAS I dont know what else to suggest lol

[Hanaldo]

Yeh cruise AFR's have been set up with the VE trim table, it was all working fine... I don't think it is heat related either, as even when the motor is cold my wideband is reading very rich. It does usually run a bit richer when cold, but never this rich. I have a feeling it's a stuffed O2 sensor. Very disappointing, has only lasted about 5000kms and 3-4 months

[89CAL]

Oh is the VE Table tied in with 02 feedback?

I dont know alot about the Nistunes. I thought when you said no 02 feedback it was a bit like mine which is running solely off the injection map with no correction from the 02 sensor

not the case?

Well could very well be your 02 sensor

borrow someone elses and see if it fixes the problem?

[Hanaldo]

Oh is the VE Table tied in with 02 feedback?

I dont know alot about the Nistunes. I thought when you said no 02 feedback it was a bit like mine which is running solely off the injection map with no correction from the 02 sensor

not the case?

Well could very well be your 02 sensor

borrow someone elses and see if it fixes the problem?

Oh no no, the VE table is the Volumetric Efficiency. Basically the primary fuel map on the R34 ECU can only go as high as 14.7 as the whole map is flagged for O2 feedback and it can't be switched off. So when tuning the cruise AFR's without O2 feedback, you set the cells in the primary map to 14.7 and then trim them using the VE table until you get your desired AFR.

Will try to find someone with an AEM UEGO near me, don't know anyone off the top of my head though.

[89CAL]

spend $100 at a tuning shop putting it on a dyno? Can you still use a consult to check the sensors? I think you can with the nistunes but not sure

If so take it to a workshop with one of them and a dyno and see what voltages the 02 sensor is putting out etc.

I have an AEM UEGO but I'm a fair way away from you

[Hanaldo]

Yehh I might have to, will have to wait until the new year though. Ah well, thanks for your help mate

[DVS JEZ]

Have u tried recalibrating the wideband?

[Hanaldo]

Can't do it with the AEM's

[bubba]

Are you sure? or are they self calibrating?

The Innovates we use require calibrating every so often, you have to take them out of the dump pipe and calibrate in clean air or you get quite bizarre readings.

[Hanaldo]

Yeh the AEM's are supposed to be self-calibrating.

KEY FEATURES

• No free air calibration required - ever
• Accurate to .1 AFR
• Includes white and black gauge faces
• Includes black and silver interchangeable bezels
• Includes Bosch 4.2 sensor for optimum accuracy and reliability
• 0-5v analog output included for use with data loggers and virtually any engine management system
• 0-5v analog output Gasoline values from 10 to 20:1 AFR
• 0-5v analog output E85 values from 6.6 to 13.2 AFR
• 0-5v analog output Ethanol values from 6.14 to 12.3:1 AFR
• 0-5v analog output Methanol values from 4.4 to 8.8:1 AFR
• 0-5v analog output Lambda values from .68 to 1.36:1

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[bubba]

Hmm ok then, scratch that idea

[89CAL]

Yep, AEM's never require free to air calibration. Have a resistor circuit built into the sensor harness (or something like that anyway)