Made some search but could not find answers to my questions...

Here it is: what would happen if I run without the stock narrowband O2 sensor. Let's say I'd use the unique DP bung to place a wideband linked to a gauge. It's pointless to plug the wideband to the ECU as it will not read the wideband info proeperly.

No stock O2 sensor: what will happen?

My major mods:
- HKS RS intake
- 3" DP
- 3" rx7store HiFlow cat
- 3" catback
- PFS IC
- efini Y-pipe
- Knightsport ECU supposed to support these mods

Thanks for the input!

 

with the mods listed why do you need a wide band anyway?. the knightsport ecu is not tuneable. the knightsport ecu will need the stock o2 sensor for feed back. the car will run bad and very rich.

Jeff

 

i know some have done it. only symptoms i've heard of is rough idoling

 

Buy a wideband that has a NB output to connect to your ECU.

 

I did this for about a week before installing my EMS, I wanted to get an idea of what the OEM ECU was doing in terms of AFR's, but didn't want to install a second bung in my downpipe. I tried connecting the 'simulated narrowband output' of my AEM UEGO gauge to the stock ECU, but the stock ECU didn't seem to like it: it would hesitate sometimes at part throttle.

With the stock sensor completely unplugged from the ECU, the car seemed to run OK; I didn't notice a loss of power or significant decrease in fuel economy. If you think about it, most narrowband sensors are only accurate around 14.7:1 AFR, so the stock ECU shouldn't be using it when in boost or at idle. I imagine it would only be used when cruising.

-s-

 

The reason I ask is twofold:

1/ a friend of mine ran w/o his O2 sensor (DP, StockCat, Catback, open intake) and noticed NO difference
2/ I read here and there that with a midpipe the O2 sensor is useless...

 

If you get a Power FC you definately could. You can just turn off the O2 feedback.

 

Thanks for all the inputs guys.

Someone knows a wideband that has a narrowband output connectible to the ECU and that is working well? (from what I read from Scotty305 the AEM is not so good at it).

Also, anyone has already run w/o is narrowband sensor on or disconnected?

I've heard and read from some people that they didn't notice any change: OK, then may be I can try this. But even if you don't notice any change, can it be bad for the rotary?

I must say that I must run already quite rich considering the numerous backfiring I have (no flames but farts for sure)...

 

up

 

Lots of people do, however those people are using programmable ECU's where they can ignore the stock O2 sensor.

On a stock ECU? It not necessarily bad for your car, but if you have any sort of emissions testing in your area, it will most likely cause an overly rich condition at idle. That will most likely fail an emissions test (not to mention an engine code being thrown).

Some people have noticed a difference with an O2 sensor change:

https://www.rx7club.com/showpost.php...56&postcount=1

On the stock ECU, it will hurt your gas mileage if it's gone or bad. It's also possible for it to cause some low rpm hesitations.

 

Thanks Mahjik!

My ECU is a stock JDM remapped by Knightsports, so I guess already richer than normal.
My O2 sensor is brand new.

I guess I'll try and find out by myself what would change, doesn't seem to be dangerous for the engine, so...

My purpose is just to plug a wideband to figure out if I'm fine with this ECU on or if need a tuneable one.

 

i just found out recently i wasnt running a wire to the O2 sensor :| anyone know where on the harness the other end of the wire goes?

 

I too have a AEM UEGO wideband o2 with a secondary simulated narrow band output. Plugged this into the Apexi PC but had problems so turned of o2 input; ever since car ran better than stock.

 

It is right behind the uim should be a black plug with yellow on the inside and a ground wire attached to it.