wacky wideband

[LETZRIDE]

long story short...I just installed a new AEM wideband + gauge into the car about 1.5 weeks ago...it seemed to be reading fine, more or less what the car should be at...I have not touched the tune from the summer time other then pulling out some timing, and changing the T stat temp for the 180...I slid into a curb new years eve and cracked my front drivers side rim...got it all fixed up, had the mechanic check the car over...my Y pipe had been a tad loose before this so I had that tightended up...

Now, all of a sudden the wideband is reading wacky numbers...it seems ok at idle, 14-15 afr...when driving it stays around this as well...but when cruising it will start going up to 17-18 then off the scale afr...I left off the gas and it goes back down to 14-15...then it will go down to 10-11 afr and stay there until I either let off or give it some gas...then fluctuate back to lean...

When it hits lean you can very very subtly and I mean subtly feel a bit of a bog, but this is not all the time it hits it...

anyone have an explanation for this?


I was reading some guys saying they read lean when they had a leak at the Y pipe...but its going between the two extremes of rich and lean...but if you let right off the gas its at 14-15...so Im on the fence about a bad sensor?

[97rs4life]

Re: wacky wideband

I had the exact same issue with my car after my rebuild. I would be driving for 5 minutes and then all of sudden while cruising my a/f ratio would hit 17-18 until I played with the throttle. Then as soon as I held the peddle steady again it would either go way rich or way lean once again. I had a couple tuners check it out locally and they were all baffled why the a/f would go crazy like that. Monitoring my o2s they would change too so it wasn't the wideband either. I never did find out what causes it either. I now run my car in open loop the whole time and just have my MAF tuned correctly for the desired A/F ratio. As soon as I went into closed loop it would go crazy on cruise A/F ratio. Runs great for me now in open loop.

[LETZRIDE]

Re: wacky wideband

I had the exact same issue with my car after my rebuild. I would be driving for 5 minutes and then all of sudden while cruising my a/f ratio would hit 17-18 until I played with the throttle. Then as soon as I held the peddle steady again it would either go way rich or way lean once again. I had a couple tuners check it out locally and they were all baffled why the a/f would go crazy like that. Monitoring my o2s they would change too so it wasn't the wideband either. I never did find out what causes it either. I now run my car in open loop the whole time and just have my MAF tuned correctly for the desired A/F ratio. As soon as I went into closed loop it would go crazy on cruise A/F ratio. Runs great for me now in open loop.

thats strange...I gotta get the tuner on it today before I damage something...damn thing was fine before I smoked the stupid curb...

[Blizzard242]

Re: wacky wideband

Eh.. my wideband never hit a curb. It's just always been off. my stoich is about 15.2

I'm throwing mine in one of the stock o2 sensors this spring to really tune it. Rather than the extra rich I've apparently been doing.

[Fondle]

Re: wacky wideband

your tuning a turbo'd car with a sensor before the turbo?

[ssms5411]

Re: wacky wideband

There are 4 stock 02 sensors on mine at least. 1 in each manifold and 1 before the Cat and 4th after the Cat, I had mine put right next to the before cat , even though I'm not running a Cat its straight through. But when the turbo goes on, it is good to have the wideband at least 12"s from the DP, so it doesn't get too hot and burn it up. EGT sensors go before the turbo.

[ssms5411]

Re: wacky wideband

long story short...I just installed a new AEM wideband + gauge into the car about 1.5 weeks ago...it seemed to be reading fine, more or less what the car should be at...I have not touched the tune from the summer time other then pulling out some timing, and changing the T stat temp for the 180...I slid into a curb new years eve and cracked my front drivers side rim...got it all fixed up, had the mechanic check the car over...my Y pipe had been a tad loose before this so I had that tightended up...

Now, all of a sudden the wideband is reading wacky numbers...it seems ok at idle, 14-15 afr...when driving it stays around this as well...but when cruising it will start going up to 17-18 then off the scale afr...I left off the gas and it goes back down to 14-15...then it will go down to 10-11 afr and stay there until I either let off or give it some gas...then fluctuate back to lean...

When it hits lean you can very very subtly and I mean subtly feel a bit of a bog, but this is not all the time it hits it...

anyone have an explanation for this?


I was reading some guys saying they read lean when they had a leak at the Y pipe...but its going between the two extremes of rich and lean...but if you let right off the gas its at 14-15...so Im on the fence about a bad sensor?

Did you ever add fuel since the colder weather will make it run leaner, I have a summer tune and a winter tune becuase in the winter it runs .5 or more leaner. The temp here is a big change, from 115+ summer then down to 40 degrees in the mornings in winter and high of 60-70 degrees , so a 50 + degree change will throw off your A/F readings, I ususally use PE and add 0.500 for winter and run 12.6 A/F.

[Blizzard242]

Re: wacky wideband

your tuning a turbo'd car with a sensor before the turbo?

No, i'm tuning a N/A car with a sensor before the turbo.

No Fondle. And don't ask me questions anymore either. I'm done with you.

[Fondle]

Re: wacky wideband

nvm...

ninja edit

[LETZRIDE]

Re: wacky wideband

Did you ever add fuel since the colder weather will make it run leaner, I have a summer tune and a winter tune becuase in the winter it runs .5 or more leaner. The temp here is a big change, from 115+ summer then down to 40 degrees in the mornings in winter and high of 60-70 degrees , so a 50 + degree change will throw off your A/F readings, I ususally use PE and add 0.500 for winter and run 12.6 A/F.

I havent added fuel yet no...but my tune from the summer was running rich anyways...I was running it rich to stay safe.

The wideband itself never hit the curb...neither did the pipes...just my left front tire, and it cracked the rim...BUT, since that point I have had wideband issues (even though the pipes are on the other side of the car)

I have my wideband in the stock O2 sensor location...the one right before the cat...its been like that since Ive owned the LC1 and I have never had an issue like this...

This is something that literally started less then 1 week ago, and the only thing that has been changed in the car since just before this started was the T stat....but not the tune, I had the tune changed for a 180 T stat about 2 months because I was intending to swap back over, just never had time till now...

[Fondle]

Re: wacky wideband

how old is the sensor?

[Blizzard242]

Re: wacky wideband

I'm gonna take a stab at the problem.. Possibly when you hit the curb, or even when the Y-pipe was tightened it could have caused a leak in one of your header gaskets. Thus throwing off your narrowbands and obviously the wideband. Just a guess though. Have you tried running in open loop?

[LETZRIDE]

Re: wacky wideband

how old is the sensor?

brand new

I'm gonna take a stab at the problem.. Possibly when you hit the curb, or even when the Y-pipe was tightened it could have caused a leak in one of your header gaskets. Thus throwing off your narrowbands and obviously the wideband. Just a guess though. Have you tried running in open loop?

Im going to be putting a new tune in tommorrow...if I can't get my tune without the maf to work flawlessly like I want, I will try an open loop change only...

[LETZRIDE]

Re: wacky wideband

I put it into open loop and it seems to be a bit better...although it is commanding 16 afr on cruise at around 40mph and I dont know why...my narrowbands are confirming the lean spikes on the wideband...I have no idea why this is starting to happen...the tune was fine 2 weeks ago...

I tried my tune without the MAF that I will be using with my ITB setup that was working beautifully in the summer and I swear I just about popped the engine...at WOT it went lean as sh*t, 17afr...only God knows why...all the numbers add up and it should be in PE mode at 10% throttle...my only thought is that the VE table is not up to par with the air that is coming in from the winter time...and I say that because it was commanding 13.1 but getting 17...narrow bands confirmed this with 78 mV and 26mV respectively...

all my gauges have been starting to go weird lately...when I put the car to the "run" position, sometimes my rpm gauge will shoot up to 2000 rpm then to 1000, then 1500, then kinda hover around there, then slowly come down to 0....my oil pressure gauge has been hanging around the 1/4 mark...which is not far from what it normally is...when driving it goes to around half way...but it just seems a tad lower then normal...I dont know whats going on...

[ssms5411]

Re: wacky wideband

Wish I could help , but it seems you have covered everything I would try. Good luck to ya.