What could possibly cause 14.2 AFR @ Idle
 

Hey guys having a problem with my car running rich on IDLE.

Here's what I've done.
Took apart my FMIC and retighten everything.
Brakebooster line tightened.
The line that connects from the BPV to the intake manifold, also tightened.
Line connecting from TIP to BPV
And turbo inlet to turbo.


This happened after my PG V3 Exhaust manifold install i believe (i am not 100% sure)

Is there any other way that it could cause 14.2 AFR @ Idle?
WOT logs seems fine.

(tune was after everything was installed, MAF calibrated and everything)

This
http://www.mazdaspeedforums.org/foru...ml#post1183918

Of course I did mine on purpose but maybe o2 sensor related.

Exhaust leak. Look for a crank in the manifold, or signs of a gasket leaking.

@himurax13; knows exhaust leaks

tapafuck

Damn you , quite whoring me out. Its not like I know anything. ;)

Post a WOT Log. How is your fueling at WOT? Do you have a VDyno pic?

Is your idle smooth or rough? If youovertighten a clamp, it could cause a leak.

If it is an exhaust leak, you could also take a barbeque lighter and run it around the edges of the turbo to downpipe gasket, turbo to exhaust mani gasket, and around the entire exhaust mani gasket on the head. If the flame gets blown out, you found your leak. Also look for large amounts of soot.

I've always though exhaust leak would make it run lean or something. Alright Guess I'll retighten every possible bolts tomorrow. If not, I'll just wait until BNR3 install

Any update on this, I have same rich AFRs at idle and cruising, last mod (BNR and downpipe) installed 3 months ago...
There are no any obvious exhaust leaks.
WOT AFRs are on spot.

What are trims?

14.0-14.5 is normal AFR at idle. At least for me.

Here is part of the e-mail which I've sent to @Lex; so I don't need to retype this again.
-----

1. When I start the car, it is running in open loop for first ~20seconds and it shows steady 14.81 AFR, after that it goes to closed loop,and I get 14.0-14.4 AFR readings, I can leave it at idle for 1 hour and it will not lock at stoich 14.7.

2. When I stop the car after driving, AFRs are at 13.0-13.3 and then after few seconds they jump to 14.0-14.4 AFR, again never at 14.7!

3. While I'm cruising, AFRs usually oscillates from 12.9-14.4, but 70% of time they are at 14.0-14.4 range, so again no stoich values...

4. Car behaves and sounds just normal, LTFTs are currently at ~-6-8% while idling and cruising, and STFTS oscillates +-4.

It targets stoic. So 14.7

Yep, thats right it targets but never hits stoich :)

Bizarre that your trims aren't maxed.

Really strange.. maybe ebay DP leaking before O2 or something..

@kish89; I have youre EXACT same symptoms.

But I am also certain that I have an exhaust leak at the manifold. Pretty sure that this is what is causing my problem.

When did this issue start for you? Was is right after your install of the bnr or just recently? Also did you replace the mani gasket after you re-installed the exhaust manifold?

I got new gasket coming in today I'll be taking out the manifold and inspect then install it. I'll update within the week or two. Working extra shifts for black Friday

Well, I'm not sure when exactly that started, but I'm keeping my eye on AFR for last 7 days (after I've changed primary O2 because of other issues http://www.mazdaspeedforums.org/foru...erking-129161/ )

But I'm 100% positive that the same thing was happening with old O2 sensor while it was still working.

I did not change my mani gasket after reinstalling (yea I know :lame: )

Only leak which I had was at mani-turbo connection, two of four bolts were out:
http://www.mazdaspeedforums.org/foru...-turbo-121253/
That was fixed and no leaks there, at least I can't see them.

I have some 8 months old cruising and idle logs, and AFRs are in place, but I was stock then (except intake+sri).


Who knows, maybe there is some small leak between turbo and DP, I can hear some ticking/rattle sound while slowly accelerating from 2k-3.5k RPM.

So it wasn't acting up before the bnr install?

If not, I would be looking at the manifold for signs of a leak (soot). These gaskets aren't really made to be used more than once.

Well my mysterious exhaust leak was finally traced down to one of the CHRA clamps. One of the bolts fell out and the threaded hole was leaking exhaust from the hotside. It was extremely hard to find because the only way to see the hole is from the bottom and looking at it from the driver's side. I used the barbeque lighter trick to find it.

Unfortunately my AFR's were spot on except at WOT (where it became erratic), so I am not sure that this might be your problem.

I could not Bolt, that hard to get nut under the CNT DP, but i dont think i am leaking, here is a log A/F looks good i think. targeting 11.6 A/F, idle 14.3-14.8

Check your rear o2 sensor. i bet it's not all the way in

I don't know if that could cause those strange AFRs but I have extender(plug fouler) for secondary O2 sensor so I don't throw a CEL because I'm running catless.
Maybe I should try to remove extender?

Here is a little video of DH monitoring (startup-idle-rev).

I had the same exact issue. Idle afrs are controlled by the rear o2 sensor. It's not getting enough air and I think not warming up enough or something. Try teling out the extender. I had one on my old dp when I had the issue, and now with my new dp with no extender, my afrs are spot on and surprisingly I don't even have a code.

Get rid of the stupid fouler and just tune the code off in atr.

Well, fouler is out, but AFRs are still crazy, pretty much the same behavior.
Good thing is that I didn't get any CEL, so I'll just leave it without fouler.

I'm having this same issue and I'm popping a few different o2 related codes. From the threads I've read it could simply just be cold weather... Mine started after it started dropping under 50*

Everyone needs to check for exhaust leaks or other post turbo leaks.

My rich at idle problem was rectified with a new ex mani gasket.


And also mass airflow sensors, by design, are able to account for changes in air mass (ie. temperature). So it would seem unlikely that the cold weather would cause this.

The threads I read mentioned something about aftermarket cats being less restrictive, and the colder temps in combination with power egt's is enough for the sensor to get low voltage or no activity readings, which are what I'm throwing. But Idk anything lol...

Oh ok. I thought you were implying that the maf sensor was the cause.

That theory that you mentioned seems like it could be plausible. Link to that thread where you saw it?

Tapa

Found a minor leak on the exhaust manifold area. But I'm not going to switch it out until my BNR3 is here.

On the meantime. I took out my plugs and checked it.. on cylinder 1 and 4, it was grey ish.

cylinder 2 and 3 had white tip. Don't know what to think of it =\

Also note, cylinder 2 & 3's spark plug was pretty darn loose. Think this could've caused the tip to be white?

http://sphotos-h.ak.fbcdn.net/hphoto...41833168_o.jpg

Problem solved, it was tune related.
Versatune was reinstalled and now my idle/cruise AFRs are almost spot on.

Also, fuel economy is improved:
Before:~15MPG
Now:~18MPG

Like reflashed?
When i reflash my 93 tune, it would be 14.6-14.7 AFR @ idle for like 10 miles, then drops back to 14.2 afterwards.

1.Uninstalled Versatuner (back to stock mazda map)
2.Installed Versatuner (versatune base map)
3.Flashed Lex tune

After 300miles, AFRs are still spot on :)
You are probably using AP, try with this procedure, but I think that this issue is only Versatune(or my ECU) related.

Yep starting to drive me nuts. I'm gonna get some pics of how my o2 sensors mounted today. @SilverDemon; thinks that could be the problem. What all codes are you throwing?

http://i287.photobucket.com/albums/l...0/IMAG0698.jpg

Are the LTFTs stable and no more than +/- 10? If that is the case then the ECU is NOT trying to achieve stoich. That means that either a fuel table is not set correctly or there is a bug in the flash. Completely uninstall the AP, update it, and reinstall it.

would you like me to go out and capture an idle log real quick? last time i remember looking at it, it was jumping from -9 up to 2 randomly. @SilverDemon; thinks its an issue with how the o2 sensor is mounted in my cp-e dp. heres a link to my thread so im not cluttering up this one. im gonna mention a few people i have noticed with the same problem too, i wanna get to the bottom of this issue.

http://www.mazdaspeedforums.org/foru...-codes-131794/

A log is always appreciated.

This exactly the behavior I had when I was using the diode fix on my rear O2 sensor.

I'd check for leaks between the two sensors and make sure the rear O2 is tight. Then try a known good rear O2 sensor...

Thank God for the search button.
Im also having this odd occurence....however, not as bad as the OP.

So, I recently installed my COBB DP about 2 weeks ago. I have no leaks what so ever. Ive checked multiple times.

However, I also installed the COBB SF Airbox at the same time, and it seems its changed my 0-5.7 g/s trims from its usual -4, all the way to roughly -8, sometimes -9 if i let the car idle over 20 minutes to warm up in -20 degree weather.

On top of that, my AFR at idle is no longer 14.7 like it was on the stocker, im now sitting at 14.5 and holding perfectly at 14.5. Crusing is also 14.5.

WOT is on target at 11.6 tapering to 11.4 .

Should i jack it up and see if that rear 02 needs tightened ? Im positive i torqued it down to the proper specs with a calibrated torque wrench.

I dont have any codes, i was just wondering if sitting at 14.5 is not good and or i should be at 14.7 no matter what.