My LTFT's are not reading at all. They all stay at zero, while the STFT (oxygen feedback) reads just fine. Is there something wrong with my ROM for it not to read properly, or at all?

I just replaced my front o2 sensor and it kept throwing codes at me (P0139).

Any help would be appreciated...

 

If you have a faulty o2 then that would affect trim reading.
Try disconnecting the battery for 30sec, resting the ecu, keep the engine running for 16minutes, idle & then read the trims.

 

What rom are you running? I know there's a issue with the tephra v7 if you disable the rear O2 on the periphery bits that causes you to not get readings on your trims for some reason.

 

I just replaced the front o2, along with after install unplugged the battery for at least a good 15 minutes, etc. I should have posted that in the OP, sorry.

Im on a tephra v7 ROM since I have a dual map for 91/e85. Where would I go about to enable the rear o2 sensor? Sorry kind of new to this enable/disable stats.

 

Thats not a tephra V7 issue.

If you disable the rear 02 using the periphery bit on ANY ROM, it makes the fuel trims stop working.

Tephra V7 fixed that, by offing a rear o2 simulator.

 

So I went in and re-enabled the rear o2 sensor i believe, and it still does that read?? What other suggestions should I try? Or would it be better to for you guys to look at the ROM?

 

Try adjusting yr Evoscan say move the LTFT bars higher...Ive been thru yr frust, and finally got it figure out by just moving the fuel trims bar higher on the Evoscan...No harm trying...

 

What is your idle AFR reading?
Try a stock rom to rule out any rom issue.
I've had one car that did this, the solution was to rest the ECU & go for a cruise trip first (before idle running), continues with no stops for 15minutes, 35mph. Then ran it at idle for another 15min, both trims appeared!

 

frasch did you ever figure this out?

 

Sorry to bring this thread back from the dead, but I just found it
I'm trying to log my ltft and can't but my rear o2 is removed and is set to 0 in the periphery bits. I've activated o2 rear sim but still no joy. I'll try to put the periphery bit to 1 and hope it won't throw any cel...
Should my LTFT start to populate right on start or will it take at least one idle cycle (4 min from what I've understood) to get datas ? I've seen that I need to make the car run for at least 16-20 min for it to be accurate but I don't want to wait too much for nothing

 

You need to enable the periphery bit, enable o2 simulator in the tephra mod options, make sure that the read o2 heater patch data isn't set to all FFFF.

The idle trim will update from 0.0% after 4 minutes.

 

Waoah, that was fast Thanks. What is the address for the rear o2 heater patch data ? Is it visible from tephra v7 ?

 

its in the tephra mod options it should have been one of the first expandle menus. i forgot the tables name

 

Thanks, I'll check all this tonight and report back tomorrow

 

Great, I've just done all this, so as a reminder :
- put the rear o2 sim
- set the rear o2 in the periphery bit to 1
- disable the rear o2 heater by setting it to 0009

And it started display low LTFT.
Nevertheless, she doesn't want to enter closed loop under 1200 rpm, maybe because of the kelford 272 or the size of injectors DW1000, or should I change something in closed loop settings ?