NefMoto

Been working on the car and i ve run into another hardware issue the car runs super lean only after 5200 rpm in 3rd gear only

1st and 2nd are 100% ive got a steady afr of 10.9 during 1 & 2

i ve swapped fuel pumps between 2 brand new 044 bosch pumps i ve got brand new stainless lines straight to my ie billet rail on deka 630's

no idea whats causing this can someone point me in a direction

short clip of whats happening

http://www.youtube.com/embed/p-fpXiHzEUI

possible vac leak post maf, pre-inlet?

i.e. sucking in unmetered air.

Gonna smoke and presure test again

if it was running that lean i would expect a power loss, or detonation, is this happening? i have run into issues where the AEM sensor goes bad and does that same thing

im not sure if yours is narrowband or wideband? logs would help

graphs

you sure this happens only in 3rd gear?

I ll make a video of going through gears its perfect through 1 and 2

Where's the wideband mounted?

Edit: also, you're running a 1.5 points richer than target, then suddenly off the charts lean?

make vid of higher gears 3rd up then. just say in the vid its on a closed course in "Mexico" lol

I'd think if it were actually going lean it'd show in the timing CF's.

i have to do it super late tonight if the weathers nice due to 4th being over 130+

i agree with dillenger, anytime I have lost fuel pressure, and or been way to lean, there was a ton of knock, a huge loss of power, according to that gauge you were past 16.0 which I think is that gauges range.... where is it located?

me or the gauge location ?

Where is the sensor mounted (my question from above)?

not my exhaust setup just for visualization 

sensor location on my down pipe on the top portion so that minimal condensation builds up when powering down

That could be the problem. That's too close. Any reason that you didn't just use the rear O2 bung?

Wideband sensors are extremely sensitive to temperature and exhaust pressure.

It definitely looks like the problem is with your sensor, gauge, or installation.

i ordered a new sensor and going relocate further back
i have custom piping from down pipe all the way back never had rear o2's

any updates on this? i'm pretty interested to see what the cause was.

got a new sensor gonna drop it in this week and move the sensor back towards where a rear o2 would go

It seems logical to me to put the sensor bung as close to the stock position of the S1 sensor/s as possible. maybe even the same distance from the turbo as the stock bung, just at the opposite inverse position or other acceptable angle on the exhaust pipe. Not good if they line up with each other and the flow. I suspect one of the sensors would get a bad reading because the one in front of it would be deflecting gas flow if they were very close together. just a thought really..I have no data that supports this "theory".  I put my wideband sensor next to the stock S1 position on the DP at a different angle as if you were looking into the pipe. It works just fine, very responsive and I can reference it against the stock S1 sensor (mine's a factory wideband) and vice versa.

I did put my EGT sensor as close to the turbo outlet as I could though. I thought about welding in bungs(EGT) for each cylinder(1.8T) but maybe after I graduate from novice to amateur tuner as I'm not that good yet to tune individual cylinders...I wrote my first tune the other day, I had a successful flash and the car didn't blow up, so YaY for me.

I think what Phila meant when he asked why you didn't use the rear o2 bung is because chances are you deleted it in your tune and the bung is there still and not being used. Not that it's the best place to put it, but most convenient. but not for you since your custom exhaust never had them installed  :D

i have seen tons of cars running them as closest possible to the turbo outlet getting accurate readings i got my car with it placed there never thought anything of it . All i could think of is it made read more accurate but kill the sensor quicker .

Did you mean as close as possible to the turbo outlet? If so, I have seen this also and shared your thoughts about reliability but not accuracy. I'm not so sure accuracy would be better. I haven't researched much about this subject though.

derr... I just thought of this. swap the sensor plugs and run it to see if you get the same results.

Do some more research on WB O2 sensors.

Simply looking at the FR can give some insight.

So i fixed the issue of the car going super lean after 5200 rpm. I ripped apart my plumbing and tested everything made sure everything was on tight. At WOT my afr now is a steady 11.4 car runs ok at higher rpm it feels like theirs a little hesitation. Also the car feels slow. Everything is less than 2000 miles old. New turbo new maf new everything. When i run the car with the maf unplugged it feels a little quicker and less hesitation.

Heres my most recent log. I also moved the uego o2 to the proper place.

Thanks Guys

Pretty much everything is a mess there.

Your req AFR is a mess

Your boost isn't even close to requested.