extremely lean at Idle

[thricestrat]

Hey guys maybe you can shed some light on this problem. Im still working on my car to get it ready to Daily drive. Im running a B16g, and at idle hitting between 16.0:1 and off the scale (AEM Wideband installed in rear O2 port w/ no cat, Megan DP and Apexi Exhaust). I am buying new injectors soon.. thinking about 650's because I wanna run 20psi (goal as of now). I have the stock injectors in, with AFPR, Walbro 255 rewired, upgraded lines, Brand new Filter, and MAFT. I tried to tune my MAFT to richen it up but as soon as I turn the knob the car bogs and dies. Which Injectors would be best for me? I would rather just drop-in's (no High resistance ones). And yes im buying link and logging as soon as my wallet says its OK. What would ### such a lean idle? If I give it a small rev it runs 14.7 to 13.0 then right back to super lean.

Thanks in advance guys

 

[96_charcoal_tsi]

Just wondering if any one has any other ideas for this situation? I am having a pretty similar condition. At idle the wideband will peg out at 17 afr and while cruising it will stay a little lean at like 15.2-16.0. Under wot though I run perfectly fine and stay consistent at about 10.5-10.9. I have evo injectors, evo 9 pump rewired, and stock regulator. I just replaced the fuel filter and that did nothing. I am going to through the stock pump back in and see if that fixes anything but this problem started just out of the blue. I have a safc to tune with and was running just fine and didnt touch anything, now i am having this problem.

 

[phillabaum03]

thats not too bad at idle. Cars always run lean at idle, its when your moving when it counts

 

[delta448]

Unless it's causing knock or overheating I wouldn't worry about it at all. Some people tune their cars to run that lean at idle to conserve fuel.

 

[8urv8]

It's probably an exhuast leak. My wideband was reading really lean at idle and I later found that I had a pretty bad leak in the flex section of my downpipe. I got a new downpipe and that cured the problem. I'm having the same problem again but this time my downpipe to 02housing gasket crapped out.

 

[thricestrat]

checked for exhaust leaks. Had none, my DP is brand new as well as my exhaust and every spot for leaks are clean. I fired it up today and its reading 13.0 - 14.0 then after warm up it leans out? and I just started getting fuel cut around 4.5k. Im gunna buy dsmlink and just try tuning and logging to get a better sense of whats going on with everything

 

[96_charcoal_tsi]

A quick update on what I tried today to try to solve this problem. Put stock pump back in. Checked all connections since it is rewired. Checked for exhaust leaks found a small one fixed it and still having the problem. Took off the fuel press reg vacum line off trying to get it to run rich did little to nothing. Very little to no boost leaks. the only other thing i can think to try is to switch out ecu's or the maf to see if that will help. The o2 sensor only has like 2000 miles on it. I tried adding a ton of fuel in with the safc and that didnt help any.

 

[96_charcoal_tsi]

Some other things i have tried to solve this since the last update. I have fixed all exhaust leaks pre turbo and after the turbo. That makes for quicker spool!! I have done numerous boost leak tests and am holding 20 psi very well. Only a small leak at throttle body. I just put another 02 sensor on as well and that did nothing. I really cant think of what else it could possibly be. I still have another ecu to try but really doubt that is the problem. Any help would be appreciated. BTW the car pulls alot better with everything else fixed.

 

[thricestrat]

Update, relocated battery back to under the hood (instead of trunk). Gave me a way smother idle... picked up an safcII was able to richen it up a little bit. Gapped a new set of 6's down to .028, tested both coils and all surrounding ignition. Needed one new ignition coil so I bought both packs new. Havent driven my car yet to know what AFR ill be at with a WOT pull, but will soon as soon as I get a logger. Overall my car is running a lot better with the safcII and small changes ive made.