AFR mostly rich, erratic at times
 

Just developed this issue today and being that this is my first turbocharged car I would like to ask for some help diagnosing possibilities.

1. When I cold start the car, everything is fine at idle.
2. When I start to drive the car at normal throttle, the AFR tends get pegged at 10 after a minute.
3. Come to a stop and now my idle is 10 for AFR.
4. Now low throttle and normal throttle driving has awful response and is still at 10.
5. Every now and then the AFR gets back to normal or almost normal for ~30 seconds, and then it will go back to 10 AFR.

After some research I've found a broad list of issues it might be:

• Air filter (new one shipped tomorrow)
• MAF dirty (about to go buy cleaner and spray it)
• Boost leak (after MAF?)
• Fuel pump (I already have a 485LPH brand new sitting at home)
• Spark plugs (20,000 miles on the same plugs, never replaced since turbo setup)
• Injectors

I was hoping I could get it narrowed down a bit more before I start throwing money at it.

Hello

I'd check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.


if thats OK try replacing the 1st O2 sensor

Running wideband and the 2nd O2 is disconnected I believe. I'll check for leaks around the turbo.

Are you talking mostly about turbine housing exit to exhaust area?

yes any leaks upstream of an O2 sensor can pull air in and so give a false rich reading

you say you're running wideband, is the sensor replacing the factory wideband or is it additional?

also are you on the stock ECU with ECUtek, OFT etc? or on a standalone like Motec?

Almost positive the wideband replaced factory, I'll have to double check as I haven't even had to look at it since building the car.

I use Ecutek.

OK if the wideband has replaced the stock item and you're not using any closed loop function in your tune then it won't be effected by any leaks or faulty sensor

from the sound of it though I suspect that you are using closed loop but have changed the sensor gains so it uses the Wide band as the main input

Have you any catalogs? Might help to see if trims are at play etc?

All I have at the moment is Torque. Which I doubt can help.

I know for a fact that the 2nd O2 is disconnected. I don't know about the closed loop or not because I didn't tune or build the car. I've only taken it apart several times for maintenance and parts/turbo replacements and the occasional cleaning.

Saw some improvement on the drive home for no reason whatsoever. Was running upper 12's and 13 flat AFR for most of the ride in higher gears and part throttle. I didn't go past 8psi either, which I'm not sure if it helped the situation or not. Idles at upper 13's and occasionally 14's now as of getting home.

Sprayed the MAF and several other electrical components completely clean just now too.

I suppose I'll update tomorrow but I'm very skeptical that this just randomly "fixed" itself. Unless maybe there was some bad gas or something of the sort.

I have some gaskets on the way because I'm about to buy a new turbo anyway (different reason).

I'll post more symptoms and/or hopeful good updates as soon as they come. Thanks for the help.

STILL HAVING ISSUES
But they aren't as bad.

• Idle is now ~12 instead of 10. (Still too rich when it used to be 14-15AFR idle)
• Light throttle ~13-14AFR. (Not really concerned about this but could be better)
• Heavy throttle 10.5-12AFR. (Definitely too rich)

Any ideas? Could this just be a wideband going bad or?

Dude you gotta get an EcuTek cable and get some datalogs to trouble shoot. You still running a D3PE tune right.

I'm getting Nick's next week. Yes still running the D3 tune.

I'm literally waiting for the turbo to ship before my flex-fuel upgraded turbo project and now this happens. I just placed an order for a replacement wideband sensor though, I feel like this one has been put through A LOT of crap. It's had oil blasted on it numerous amounts of times before I originally fixed the oil problem. It just seems like a smart move regardless of whether it fixes this problem or not.

It has to be the AEM wideband sensor. Basically every tells me these things are lucky to last 2 years and I've had it for a bit more than that. Combined with said turbo oil problems above I don't see how the sensor even made it this far.

I also noticed that when the key is ON but engine off the sensor reads mid 11's. Not sure what that means.

Tried a recalibration?

I was told some time ago that the NGK sensor AFX was the best wideband if you're not going professional lab quality. It's not too badly priced either.

I'd agree that a new sensor is well worth a try as it does fit your symptoms very well

A little bit late lol. Bought a new AEM UEGO sensor off Amazon and they only charged $10 for same day shipping!

Not sure why I thought the problem would be fixed with just the wideband being replaced. There is a standard (looks to be) O2 sensor a few inches before the wideband on my manifold and I believe that's the real culprit. I hooked up the Torque app just for giggles and noticed that the O2 sensor thinks it's reading ~14.7 at idle and only barely fluctuates when I rev it, while the brand new wideband is reading mid 12's.

Pretty much a dead giveaway that the front O2 is crap. Not to mention performance has been lacking.

I should have mentioned it. I was doubting that your tuner was using your aftermarket wideband as the primary input for closed loop operation.

The real question is, WHY NOT?

I know the factory O2 is relatively capable itself but widebands are still better. Would there be any reason why they would use the factory O2 over wideband?

Was the tuner aware? I have my wideband hooked up according to this:
http://www.ft86club.com/forums/showthread.php?t=57902

and the tuner had to turn the factory secondary O2 off in ECUtek. Maybe he just didn't know how you hooked it up and how he could use it?

Because you can't, and why would you not use the stock item for closed loop. You're only closed loop at ~14.7-14.0 on the stock maps and at those AFR the stock sensor is actually pretty good. You would have to effectively switch off OEM closed loop operation and then create a custom map to run open loop with feedback from the WBO2. It's a lot of work for bugger all gain.

Thanks for the info, you learn something new every day.

I'm about to upload a couple pics of the factory O2 that I just took out. Tell me if it looks like it's in bad shape or not.

http://i.imgur.com/9dQhOYV.jpg
http://i.imgur.com/b34Nx48.jpg

Did you crush it removing it? Looks pretty normal to me other than that. Throw a little anti-seize on the threads when you install the new one.

what is the sensor volts @ idle ?? it should 2.2v with 14.7 AFR ,

That's why I bought a new one because the current one stopped reading correctly.

I don't know how I could've. Maybe I hit something on the highway that came up and smacked the sensor and ended up breaking it. I mean there isn't anything guarding it.

Well everything seems to have gotten much better and possibly fixed, just got the stock AFR O2 sensor in today and partial throttle is perfect, WOT is pretty good, and idle is decent. Probably will get better after the trims are relearned.

Hopefully time to install flex fuel E85 and the new turbo now.

Thanks for everyone's help if this truly is done.

Showed this to our tuner.

Seems you may have resolved the issue, but if it persists, he suggested checking for boost leaks.

If you never did a boost leak check after the turbo kit installation, this would be good to do regardless.

Cheers.

Yeah I did a boost leak check last week before I even ordered any parts. The majority of my searchable area was post-MAF but there isn't that much distance between the MAF and TB. I sprayed some electrical cleaner in several areas to check for bubbles or to see if the motor sputtered or changed at all. Everything was good.

My car has been much better since replacing the factory AFR O2 (upstream).

Used to have two Evos, I'd jump on the socalevo forums and do a search for your problems. It sounds like a boost leak or o2 sensor?

New afr range?

My problem is solved. It was the O2 sensor (AFR specifically), replaced it last Friday.

Idle - Fluctuates between high 13's and high 14's
Partial throttle - 13's
WOT - 12's, super high 11's rarely.

Pretty sure my tuner gave me a rich tune because they might've been afraid to go leaner, this was back when the car first came out so nobody really knew the limits of the FA20 yet.

And WERE BACK!

5 days later after the stock O2 replacement fixed everything, my car is going full 10:1 at WOT only now. Partial throttle is perfect. Idle is rich, 11-13, 14.7 sometimes.

Suggestions?

A couple people mentioned vaccuum lines could've disconnected.

Supposedly @Sportsguy83 knows a bit about that.

I know more about it then him, but that would be obvious if it were the issue. Just install your Flex Fuel setup and go get a proper tune.

I'm not getting anything extra tuned or installed until I find out this issue. It's not the tune that is the problem because I wouldn't have noticed things being worse and different.

I have the android Torque app running and I just noticed a few things:

• AFR goes full rich in only lower gears after gas fillup. Just went on the highway and everything was 13's and 14's. Before my fillup all gears were getting straight 10's for AFR on boost.
• I just filled up the gas tank after it being low and now my "EGR system" reads complete where before the gas fillup it read incomplete.

I don't know what this means but it might be EGR related. Or something in the fuel system isn't operating correctly.

On an additional note, does anyone know what the fuel rails should be seeing for pressure? I seemed to be seeing ~550-1000PSI when viewing in Torque.

Fuel rail should 450psi to 650psi at idles and up to 2000psi or 2800psi at wot

Now ckeck ur long term and short term . Is should both at 0% and max for long term is 8% . Write the numbers . Drive the car . And log the both . Then if u have tach steam . Go to test injectors. And disconnect the direct injector . The fuel regulater will stop for 5 sec . The long term willl change . Log it