Forum,


I just had a turbo install done. Two issues, one we punctured the radiator. Two, the AEM Wideband is now reading full lean at idle but registering when the gas pedal is pressed. It is pretty weird. The MAF sensor is plugged in. Would having the boost controller (manual) lines switched to the turbo do that? I can't really figure it out. I'm getting a radiator installed tomorrow lol but I really worry about the wideband reading full lean.

At idle the car is in closed loop at idle so it should not be that lean but it starts at about 15.5 and slowly leans.. This just started happening immediately after the turbo was installed.

 

Oh I used to have this problem. I can't remember though if I solved it by changing the O2 sensor or with a tune. It was definitely one of those.

Give any of those a shot.

 

It's not the sensor. A tune will not effect the Wideband output to the led. It reads what it reads. The thing is saying full like off the scale lean.

 

Could an exhaust leak result in this? We checked everything. The only thing leaking was radiator fluid and that was clearly visible, arcing out of the engine bay to the floor.

 

Does it change when you rev the engine?

 

yes, and that's the funny part. but there's no way that fuel could be escaping the air by the time it hits the sensor.

 

That's weird... And you're using what ECU?

 

Stock ECU. this has nothing to do with the ECU bro. this is something before the wideband. I just can't figure out what. it's not a little lean like, wow, that's a couple of numbers high; it's that dash dash, off the meter lean! I give her gas and it registers, the manual boost gauge (I know) responds, and then after going back to idle she slowly slips into max lean again. I'm breaking my brain over this.

 

Yes I understand what you're saying, but given that you have the stock ECU and this is happening, it suggests that it's the factory O2 sensor of yours that has gone bad, or that you don't have one installed.

Have you checked the factory O2 sensor?

 

What does the stock ECU have to do with an AEM UEGO O2 Sensor? The ECU has absolutely no direct control over the sensor. The factory O2 Sensor, the one on the O2 Housing has nothing to do with the UEGO either bro. The secondary factory O2 has been umm.... removed and replaced with the stunningly accurate AEM Wideband O2. BTW the first sensor in the setup is alive and well. Installing an new turbo won't kill my sensors but it will kill radiators lol.



UPDATE:
I just got a radiator ready to pick up tomorrow. So that will be fixed but the entire tuning process is going to be dicked up if I can't get that freakin gauge to cut it out.

 

Let me show you an excerpt of an e-mail with my tuner, I hope this straightens things out.

A little history before you read the excerpt, I had the exact same issue as you had + very rich cruising AFRs and I had no narrowband O2 sensor installed at that time. My narrowband O2 sensor was set to activate at cruising only and not at idle, which eliminated my leaning issues at idle, but my cruising AFRs were WAAAY to rich (10.0). I spoke to my tuner and this is the reply I received:

"10 FLAT afr at cruise if on highway etc means the narrowband o2 sensor is no good.
not wide band, but the narrowband o2 sensor. if the car has no narrowband o2 sensor it needs one to function properly with the stock ecu."

Now I don't know who tuned your car or how they tuned it, but eliminating the factory O2 sensor WILL alter your AFR readings without a doubt, especially since you have mentioned that "At idle the car is in closed loop", and with closed loop, the stock ecu WILL use your narrowband O2 sensor for feedback and try to get that 14-15 AFR mixture.

 

Faisalm. I don't have rich AFR at cruise it acts normal at cruise. And you are right the factory o2 sensor will effect AFR but.... everything was kosher until the turbo went in. We have to check all the vacuum lines, connections, and fittings (intake, bov, couplers). I hear what you are saying I'm not saying that the narrow O2 doesn't effect things. It does. I just don't think it died all of a sudden. It has to be something with the other stuff. I will work backwards from the intake filter. And as a matter of fact I will take your advice and get a new narrow o2. I think that one has been on for the life of the car. Please don't think I don't appreciate what you have been saying bro. I just hate not being able to drive my car.

 

So let me get this straight.... You deleted your O2 sensor a while back and replaced it with the AEM wideband and everything was normal even at idle? But now that you changed the turbo your AFRs have changed... I mean an exhaust leak could alter your readings but not by that much... I can't think of anything atm that could skew your readings by that much...

I understand your frustration sir. Theres no need to explain we've all been there hahaha... I haven't driven my car for the past 4 months so I assure you, I feel your pain.

 

Yeah, since the front O2 Sensor is actually what the car is using to make adjustments it could be it. So here's the methodology.... work backwards from the intake filter, check all couplings, check all vacuum lines in and round the intake manifold, and then check out the narrow O2 Sensor. And then replace the narrow O2 Sensor. Anybody wanna chime in?

 

Wow thats crazy im going through the same problem