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Running lean.

Morphine

Ready to race!
Location
Lower Slobbovia
So I went Eurodyne stage 2, 91 this morning...

Lean code from 2nd O2 is still there...will email Eurodyne but I dont think there is a fix.

I will probably order a new o2 sensor next week when I order the colder plugs from ECS.

My advice to anyone is, dont go catless on the 2016+ cars (Was not a problem on my '15 GTI)

My lean condition from the 2nd O2 obviously should have been rich, but the catless downpipes seem to always be a pain in the ass. Overboost, Tuning quirks, Cel's etc, its just not worth it imo (this is my 2nd catless on this platform).
 

Morphine

Ready to race!
Location
Lower Slobbovia
Getting the lean code sporadically again...with the new O2. The first O2 was fine....but who needs money anyhow?

I now think it may be the vband clamp coming a little bit loose everyday....will replace it. Another freaking 80 bucks.
 

GTIJames707

Passed Driver's Ed
Location
Fairfield CA
No one is disabling a "code", the tunes are designed to eliminate any CELs caused by running an aftermarket downpipe. That is not unsafe, it just removes that annoyance. If you need to hear that from a Tune provider for it to be valid, give them a call to ease your mind.

Your code is likely the computer saying "I think you're running lean because I'm seeing a high amount of hydrocarbons" because you have no cat. If you're not actually getting a lean code from the primary o2 sensor, there is no real lean running condition, only the catalyst monitors responding to WAY TOO MUCH EMISSIONS.

Put on a downpipe with a catalyst that claims no CELS, get a stage 2 flash that will remove the chance of CELs from running an aftermarket DP, or put on your stock downpipe. Not sure why anyone would run a catless downpipe in the first place, but that's just my 2 cents you probably don't want.

I'm looking into buying a catless downpipe, probably gonna go CTS, and i'm aware of the potential for CEL's, however, if I were to in any form get a LEAN code it would cause concern. lean meaning too much o2, which is definitely not what i'd expect.
In quote above, the user states "your computer's saying I think you're running lean, because I see a high amount of hydrocarbons" But that is exactly the opposite of the meaning of LEAN in the language of an 02 sensor. narrow band 02 sensors can only see: oxygen, or lack of oxygen. A lean code would be caused by too much oxygen, which is the opposite of too much hydrocarbons.
"Too much hydrocarbons" or a rich code would be what i'd expect with a catless downpipe, when I install this part prior to a tune, a rich code would be no cause for concern in my mind. except for the annoying CEL on the cluster.

But I got some questions. How are you guys pulling codes, viewing FFD, live data, fuel trims, ect...?? VCDS? If so, are you able to disable the cat monitor via vag-com? Or keep the vehicle in open loop? I know this MQB software is intricate beyond the majority's understanding, but does anyone what might be the effects of full time open loop operation on the mk7's?

sorry for the bump but those questions have been on my mind for a while now and I was just reading http://www.golfmk7.com/forums/showthread.php?t=20548
which had a link to this thread, which drew my attention so thoroughly it required my inquisitions about code reading/data monitoring in the factory software.
 

rafycotto

Ready to race!
Getting the lean code sporadically again...with the new O2. The first O2 was fine....but who needs money anyhow?

I now think it may be the vband clamp coming a little bit loose everyday....will replace it. Another freaking 80 bucks.

Do you have a O2spacer? if yes, delete it or if not, put it
 

Morphine

Ready to race!
Location
Lower Slobbovia
I noticed something the other day….it does not happen 100% of the time. I started making a habit of looking at the gauge when I come to a stop in traffic/light etc. It seems, sometimes (maybe 25% of the time). My ratios get stuck.

I mean I am driving casual and come to a stop normally, and within a second of pulling in the clutch my lambda starts cycling in closed loop. But sometimes it gets stuck under .90 while I am already at a full stop with the clutch pulled in. And the lambda will sit there, for more then a few seconds before the closed loop operation starts running.

I of course have no idea how to fix this or how it should exactly operate on the car, or why there is a difference between this and the stock pipe.
 

Morphine

Ready to race!
Location
Lower Slobbovia
The faults are triggered when the car runs in open loop so on cold start and light throttle. In general the lambda distance from the primary plays a role as well as how far the actual probe is from the exhaust gases.

Just rereading this.

Cold start, everything looks ok.

I kinda got used to this problem, as I have had it a while now. It is now irritated me so much I am going to drive around all the time logging it under the circumstances George describes.
 

Morphine

Ready to race!
Location
Lower Slobbovia
"I noticed something the other day….it does not happen 100% of the time. I started making a habit of looking at the gauge when I come to a stop in traffic/light etc. It seems, sometimes (maybe 25% of the time). My ratios get stuck.

I mean I am driving casual and come to a stop normally, and within a second of pulling in the clutch my lambda starts cycling in closed loop. But sometimes it gets stuck under .90 while I am already at a full stop with the clutch pulled in. And the lambda will sit there, for more then a few seconds before the closed loop operation starts running"





Ya this isn’t the problem.

As George said “The faults are triggered when the car runs in open loop so on cold start and light throttle”

I was determined to log the event tonight with vcds…so I just drove around, nice and mellow on the throttle and sure enough it popped up driving on the highway, light throttle, open loop.

It is a little hard to determine the exact moment it happens. I can only narrow it down to the particular mileage as per the error code…then look through the log around that time frame. I also cannot directly log the 2nd o2 sensors afr, only the voltage outputs.

Anyhow I looked and found an interval where the car temporarily enters open loop and the voltage drops from .75 to .09 for about 1 second, then enters closed loop again. I was watching for the light to pop and pulled off within 1 minute of it activating, this could be what George is talking about.

This cycling is apparent in other areas of the log as well.


All that is fine and dandy, but what the hell does it mean or can be done about it.
 
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