when rescaling my injectors / latency again after removing resistor box i noticed something really screwy...

my car is idling at 12.4-12.8 a/f and i the rear o2 is not logging anything. it sits at 0. if i rev the car up or the car dips slightly below the set rpm limit the rear o2 will start logging and the a/f will instantly go to 14.7 at idle and stay there. the stft will also zero out. then the rear o2 stops logging again and it goes back to 12.6 or near that area.

is my rear o2 dead? or must i cruise for it to learn or what? with it simulated it does the same thing.

 

That is really weird... of course you know the rear O2 has to read for the fuel trims to adjust, but since it is doing it with the rear O2 sim, that is what is the crazy part... What Hz are you logging at idle, you may have to adjust the LTFT Hz switch over points so that Low will adjust... just and idea...

 

yes it sits dead with rear o2 sim also, i mean it will show a number if i rev it up but otherwise hardly ever shows a number.

im logging around 45-50hz . I set the closed loop LT trim control so the idle trim registered with raising the HZ value.

I dont understand why one minute ill have stoich reading and the next it sits at 12.4-12.8 though.

Monday i will tune my mid trim and go from there.. maybe the rear o2 is just being stubborn.

 

Is it only warm starts that are bad, or is it both warm and cold starts?

 

both really.

 

just downloaded 94170715 tephra v7 to try and rectify problem. I have egr disabled and heard that is cause of many start up problems.

 

It gets a bit challenging to troubleshoot startup issues. Interesting that the WBO2 reads lean. How long after startup does it read lean? If its only for 5-10 seconds, the lean reading may just be an artifact of the sensor warming up to operating temperature.

 

seems as if it does it until open loop.

 

The car should start in open loop and then go to closed loop within about 30 seconds, so do you mean closed loop?

 

huh interesting.....well always learn something new everyday - I did not realize the rear O2 played a roll.

my bad

 

yes I do. It's a little longer than that. maybe 30 secs - 1 min.

 

Do you by chance have something other than 14.7:1 in idle cells of your fuel table (10-50 load, 0-1500 rpm)?

 

Yes 13.3 (500 rpm 10-50 load)

 

I'm wondering whether you're having startup issues or whether its post startup issues. Startup issues would be extended cranking with no sign of life. Post-startup would be it fires up in the first couple cranks, but then sputters or feels like it can't maintain itself.

 

Fires right up!