What rear O2 voltages do you read?

[relliMmoT]

Just as the title states, has anyone taken readings off their rear O2 signal?
Mine stays around .3-.4V cruising and idle.
I know the range is 0~.9V IAW the ECU pinout.

I am wondering because I thought cruising/idle was supposed to be around .7-.8V

I am thinking this may be why my car is running rich. Probably not but possibly. The sensor inefficiency code may be turned off in the ECU, I cant tell- I have ECUtek bull**** and no tuner nearby to ask for help.

EDIT: ANSWER=

Originally Posted by RellimMot

Exactly what I was looking for. Ill add that to the first post in case anyone else ever has this question. The rear O2 is functioning just fine. If the rear O2 was bad I was going to just throw my wideband in that hole (its a leak-free TurboXS catless stealthback so no worries about the cat). If the rear O2 turned out to be good like it is then I was going to have a bung welded higher upstream. I experimented and just disconnected it at the connector for a day and got no CEL.. you must've already disabled it in the ECU when you tuned it.

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[relliMmoT]

Anyone know? Anybody?

[Haelan]

The rear O2 sensor adds only very minor fuel trim characteristics. It won't make you run rich by itself.

[Uncle Scotty]

Originally Posted by Haelan

The rear O2 sensor adds only very minor fuel trim characteristics. It won't make you run rich by itself.

ding
ding
ding

[relliMmoT]

Thanks for the help. However I did already know that.
Does anyone know the voltages they are getting from the rear O2 sensor normally. Its not a completely uncommon thing to measure.

[Chi_San]

.7-1v is normal.

As long as it's a flatline and not going up and down like the front O2, it's usually fine, even if it's somewhere other than .7-1v.

Though, at .3-.4v, I'd suspect a problem, like being lean. What is your front O2 reading?

[relliMmoT]

Originally Posted by Chi_San

Though, at .3-.4v, I'd suspect a problem, like being lean. What is your front O2 reading?

I did not take a reading from the front. The front sensor is something like a 2-3.5V wavering signal if im not mistaken (according to ECU pinout).

I took the reading in the process of wiring up my Innovate LC-1 Wideband. I have all the wiring done up for the wideband O2 but in order to calibrate the analog output to OEM (to wire the stock sensor signal into the wideband) I need a USB/serial converter... Macbooks ditched serial ports.

[Uncle Scotty]

id look elsewhere for your issue

your tune may just be way too rich

ditch that ecutek garbage and get opensource and be done with it

[relliMmoT]

Originally Posted by Uncle Scotty

ditch that ecutek garbage and get opensource and be done with it

Im working on finding a way to ditch ECUtek. I just dont want to lose my Clark tune.
The tune is probably not to blame as its had the car at 304WHP/289WTQ (and probably more since my last dyno and recent mods) for the past 60,000 miles without a bit of problems.

[Clark Turner]

The Rear 02 does effect the tune. The readings seem fine to me. Should be .3 to .5 cruise and idle. Under boost it should go higher up to .8 or .9. The trouble is they are not super accurate and the sensor is all the way at the midpipe far from the engine. Any leaks in the exhaust will really this this reading off. I used 1 volt 02s for many years tuning.. Glad we have WB meters now

If the car is not running right, Let me know. I can help. But if its running right and you want to ditch the Ecutek, You will need a New or used ECU. They can be found cheap. If you do decide to go this way, I can port the map over to Cobb AP2 for you.

Hope this helps man!

Clark

[quazimoto]

Just totally remove the rear O2..................

[Clark Turner]

No.. Dont do that.

C

[MrSlowbaru]

i have no rear o2, its been gone for a long time. 16 bit ecu doesnt need it

[Clark Turner]

You would know better than me.

C

[Uncle Scotty]

Originally Posted by Clark Turner

You would know better than me.

C

they ALL do

[relliMmoT]

Originally Posted by Clark Turner

Should be .3 to .5 cruise and idle. Under boost it should go higher up to .8 or .9.

Exactly what I was looking for. Ill add that to the first post in case anyone else ever has this question. The rear O2 is functioning just fine. If the rear O2 was bad I was going to just throw my wideband in that hole (its a leak-free TurboXS catless stealthback so no worries about the cat). If the rear O2 turned out to be good like it is then I was going to have a bung welded higher upstream. I experimented and just disconnected it at the connector for a day and got no CEL.. you must've already disabled it in the ECU when you tuned it.

Originally Posted by Clark Turner

If the car is not running right, Let me know. I can help. But if its running right and you want to ditch the Ecutek, You will need a New or used ECU. They can be found cheap. If you do decide to go this way, I can port the map over to Cobb AP2 for you.

Even if I now live in Louisiana?
I would probably be having to Express Mail two ECUs to your doorstep for that to work out eh?
I didnt think Cobb AP2 could handle the amount of tune my car has. Its a pretty done up "Stage 4+" or whatever you want to call it . I do want to go open source.

Thanks Clark

-Tom

[quazimoto]

Originally Posted by Clark Turner

You would know better than me.

C

Could you explain why you need it? My understanding from the Romraider guys is if you totally ditch it all fueling corrections will default to the front O2 sensor. I have been running for almost 2 years without a rear O2 with no problems with plenty of logs with a wideband.

[Clark Turner]

Originally Posted by relliMmoT

Exactly what I was looking for. Ill add that to the first post in case anyone else ever has this question. The rear O2 is functioning just fine. If the rear O2 was bad I was going to just throw my wideband in that hole (its a leak-free TurboXS catless stealthback so no worries about the cat). If the rear O2 turned out to be good like it is then I was going to have a bung welded higher upstream. I experimented and just disconnected it at the connector for a day and got no CEL.. you must've already disabled it in the ECU when you tuned it.


Even if I now live in Louisiana?
I would probably be having to Express Mail two ECUs to your doorstep for that to work out eh?
I didnt think Cobb AP2 could handle the amount of tune my car has. Its a pretty done up "Stage 4+" or whatever you want to call it . I do want to go open source.

Thanks Clark

-Tom

Sounds good Tom.. I travel all the time. In fact, I will be near Shreveport in the next 10 days

The Cobb AP2 is FAR better than open source. Lots of features that Open source does not have.

Cya

Clark

[mattminer]

If you have some secret as to why the rear 02 is needed on the 16 bits car, it would be nice to share this enlightenment. IME, its not necessary.

Id also like to know abotu all these 'features' that the AP has that opensource does not.

OP, you dont need a new ecu to ditch ECUTek, IME Ive been able to simply marry and unmarry an APv2 to get it back to stock and ready to flash with any system you like.

M@

[Clark Turner]

Cobb wont install over ECUtek flashed 16Bit ECU. Open source wont flash over it either.

In the past you could be not with the ECutek version thats been out for a year or so.

There is no comparison to features of AP2 vs open source. The differences are way past the scope of this thread. I tune both and have for years now. I prefer AP2.

C

[MrSlowbaru]

Originally Posted by Clark Turner

You would know better than me.

C

you tuned it like that about a year and a half ago

but its prob been tuned a dozen or so times since.

it was my understanding that in a 2.0L wrx, the secondary o2 sensor functions as a catalyst efficiency monitor. so when you go catless, it becomes useless. as long as the code is deleted in romraider, you can delete the sensor.

i also thought that you need it on 32 bit ecu's because it serves two functions, it is a catalyst efficiency monitor, and it double checks the front o2 values.

but if i'm wrong, then i am wrong. i never said i was better, or that i knew more than you, i only stated what i thought was true.

[mattminer]

Hmm, interesting about the cobb reflash deal not woring on 16bit. Ill have ot think about that for a bit. I know it works with at least some ecutek'd cars that are 32 bit because I have personally seen it done.

Everytime I ask about how an apv2 is a better system I get the same vague answers. It would be great if someone that tunes on both could do a comparison one day.

I parallel it to Crome vs Neptune in honda world. On the face of it they seem the same, except Crome is free (not OS). But I can easily explain the ways Neptune is superior to tune with, and on the end user side. Ive never seen that done for AP vs anything.

On the rear o2 deal, my understanding is the same as the above poster.

[Clark Turner]

32 bit with ecutek : Cobb and open source can go over the top.
16 bit with ecutek: Cobb and open source CANNOT.

The only way to get rid of it on the 16 bit is to:

1. Throw it out in the street and let cars run it over.

2. Use the ecu has a door stop for that peskey door that wont stay open.

3. Use it as a book end to hold up books?

4. Ecu Frizbee anyone?

5. Sell it on ebay or Nasioc classifides and dont tell anyone about the ecutek (common)

6. Hardware flash the actual Microproc directly.

Clark

[dankster]

I think with opensource you have to reflash the ecu each time you want to make a change. I'm not a tuner but I imagine this would be tedious. With the AP2 you can make changes in real time. Unless they have a new opensource update that I'm not aware of. I think I read that they were trying to implement real time changes but I don't know if/when it will happen.

[mattminer]

its actually not that bad to reflash the car each time, especially on the canbus cars it only takes a few moments and there are no test connectors, but thats a valid point