Sirnixalot

iTrader: (7)

Hi guys.

I DID search and i have checked everything i have read in regards to the rear o2 disable in periphery and trying to scale the injectors.

Firstly here is my setup

Evo 3 running a USDM Evo 8 Ecu and Evo 8 MAF.

FIC 750 injectors using scaling 696 and
Latency:
4.69V 3.312
7.03V 2.04
9.38V 1.296
11.72V 0.912
14.06V 0.792
16.41V 0.6
18.68V 0.336

Using Tehpra 90550701 rom

I have the rear O2 sim activated but the rear O2 is NOT disabled in periphery.

I am using an AEM UEGO to emulate the front O2 sensor. I have the front O2 Heater CEL disabled in periphery.

I have let the car idle for 30 mins and no change to low

I went for a 30min drive keeping the airflow above 80hz (it dropped to 68 twice due to traffic, we don't have highways here so it was a slight challenge) and no change.

I can see the wideband cycle when it is doing its trim magic every 4 or 6 mins.

I saw that if you didn't have the injector pulsewidth above the duty cycle, the duty cycle will not log. Is there something similar with the fuel trims, if you don't have them in a certain order they don't log?

I have attached my ROM and a screen cap of how i have things arranged in Evoscan.

wreckleford

iTrader: (2)

I'm not sure if you are talkng about short term or long term trims.

The front heater cel delete also turns off the long term trims if I remember correctly. You can use a resistor to emulate the heater but put it somewhere safe because it will get very hot.

wreckleford

iTrader: (2)

I just looked back at a ROM I did for a 6 I tuned with AEM wideband simulating the narrowband and the heater is disabled but long term trims are working so I'm not sure.

I would try turning the heater cel back on all the same an see if the long term trims start setting. The cel delete may have different effects on different ROMs.

Sirnixalot

iTrader: (7)

Thanks for that Wreckle. The car was running on a 96430706 Tephra rom last year and it was logging fine with the same AEM UEGO setup and 02 heater CEL disabled. I tried using that same rom with no luck so i swapped over to a friends 90550701 rom since all his trims were logging.

I will take off the CEL and borrow an 02 sensor to dangle from the bay and see if that gets it logging again. If so i will buy that resistor.

stunt2

iTrader: (8)

as far as I remember too, turning off front heater affects fuel trims

wreckleford

iTrader: (2)

Yes, I'm thinking it works on 9653 and not on 9055. The 6 I mentioned is on 9653. I used to use 9055 on my car and remember having the problem.

Remember that the older Evos were 2 wire 02 so you will have to wire up the heater.

I use 9653 on my Evo I without problems. What problems were you having?

Sirnixalot

iTrader: (7)

Not really having problems with either rom other than the fuel trims not logging.
I will take off the front heater cel disable and see what happens.

JohnBradley

iTrader: (30)

The only trims that shouldnt work if disabled in periphery are the LTFT and you dont want them on anyway. If you dont have the STFT look at the O2 sensor voltage and make sure its cycling. If it is kind of cycling (not stuck at 0.0394v) there is always the possibility you are way on the wrong side of the trim range (-25/+25) one way or another.

Aaron

Sirnixalot

iTrader: (7)

The LTFT trims are not working but the STFT is logging just fine, it cycles with no issues.

I was following the "how to tune your evo" thread and getting the low and mid LTFT's within the +/-5%

I ASSume that the fuel trims are mainly to help driveability but seeing as you are adjusting how quickly the injectors open it would have an effect on doing WOT tunes.