Sr20det running lean under boost but drives fine HELP!!!

[ShooterMcGavin]

I have a S13 sr20det red top in my 96 s14
Just installed a brand new aem wideband and its leaning out under boost

MODS
Greddy FMIC
Greddy BOV
Hks mushroom intake
BC spec2 exhaust
Z32 fuel filter
BeeR rev limiter set at 6.5k
Tomei rocker stoppers
Tomei fpr
Aem wideband sensor mounted in test pipe 40inches away from turbo
walbro 225

Car idles perfectly around 14.3-15.3 a/f
Vaccum is at about 20
Cruising is around 14-16.5 depending on load
Right when I hit boost a/f leans outs 17+ and at WOT it's around 15
I know this is bad but my car feels fine, it doesn't stall out doesn't break up under boost and it reaches 7psi boost
I looked at all my spark plugs and they were all light brown like they should be but I replaced them anyway along with the fuel filter.
I tried unplugging my MAF and my idle dropped a bit then went back to normal and a/f read a steady 10.0 then went back up to 14.5 when I plugged it back in.
I'm not sure where to go from here I noticed a small leak on one of my fuel lines by the pcv valve and I replaced it but still no luck.

[s13drob]

How much boost? And ECU?

[sil14zenki]

maybe try hard wiring fuel pump relay

[ShooterMcGavin]

Stock turbo injectors ecu and walbro 225 fuel pump. 7psi boost

[zurud]

put back stock fpr with stock reference point.

[Kingtal0n]

bad fuel pump, wrong fuel pressure (check regulator reference line), bad/dirty maf, need tuning


most likely candidates

[Mikester]

Boosting anything over stock, your SR is likely to lean out. The problem is not the FPR... It's that the 370cc injectors can't keep up with the fuel demand given the greater air volume at higher boost levels. A Walbro 255H.P. or AEM pump will definitely be worthwhile, but will not fix this (experience talking).

Even with the OEM injectors set to run at 100% duty cycle, they will not be able to keep up. My recommendation to you if you'd like to stay relatively low-budget is AEM fuel pump, 550cc injectors, Z32 MAFS and a JWT or Enthalpy tune. Do this and leaning out even at 16-17psi will be a thing of the past.

Additionally, as mentioned above, wiring in a 12VDC relay directly to your pump & battery will guarantee you are getting max flow at all times- VERY important when adding additional boost into the equation...

Mike

[ShooterMcGavin]

Appreciate the responses. Engine is stock boosting 7psi so it shouldn't be leaning out. I've already tried stock fpr, replace fuel lines, cleaned MAF. Going to try new O2 sensor, recirculating my bov, and test the wideband sensor again. My car pulls hard and doesn't break up under boost which is why I'm confused. Hopefully it's just a faulty sensor

[quanolvip]

Stock turbo injectors ecu and walbro 225 fuel pump. 7psi boosthttp://goo.gl/tVxTl6

[ShooterMcGavin]

Hard wired my fuel pump with a relay and still no change. Any ideas??

[ShooterMcGavin]

Update. Hard wired fuel pump- no change
Boost leak test and fixed 2 leaks- no change
Plugs are white and Wideband reads 15/16 at WOT but pulls hard to redline with no misfires or breakup. At idle wideband acts normal and I see 10/11 when reving but under load it's lean.
Fuel pressure is at 48 with vac hooked up, I know that's high but it idles lean if I lower it

[Crazyced]

Check fuel pressure at WOT and see if it drops.

[jedi03]

I have same wide and and I smell fuel...I'm debating about whether wide band is reading correctly...what version are you using?

[ShooterMcGavin]

Aem UEGO 4110.
I tested the sensor and it passed but my car shouldn't be driving this good at these numbers

[cotbu]

Aem UEGO 4110.
I tested the sensor and it passed but my car shouldn't be driving this good at these numbers

I tested the sensor and it passed, but my car shouldn't be driven at these numbers
fixed!

[ShooterMcGavin]

could a bad knock sensor cause conditions this lean?

[cotbu]

yes, and other symptoms as well, it depends how long you drive with it.
it might start limiting to a certain rpm or just make you super rich at idle etc.

Sent from a Highly Boosted Note 4!!!

[ShooterMcGavin]

Got a new knock sensor and wiring specialties harness but still no luck

[ericso3745]

This may sound stupid but it happen to my car, my air filter was to small lol, try taking ur air filter off the car for a few runs and see if it changes at WOT, at idles it will not run right but just try that and see if it changes anything and let me know

[ShooterMcGavin]

I'm running the stock rubber intake hose with an hks mushroom filter. I doubt it's too small

[Dboyizmlg]

Might be a faulty ecu.
What motor do you have black top(fins on head), or redtop?
Try borrowing a friends ECU and see if there is any change.

E5, and 62 ECU is kinda interchangeable. But you might just need the proper ecu.

[ShooterMcGavin]

Redtop SR with #62 ecu. I'm going to try a new ecu after I replace a downpipe gasket. I have to have a leak somewhere because at these numbers my motor should run like crap but it doesn't but my plugs are still white !?

[ericso3745]

Like I said it sounds stupid but it happen to my car and I had the same hks filter just try running it without the filter and see if it changes anything it cost u nothing

[jedi03]

Get rom tune...just got mine back from enthalpy and 11.5 wot so fun!!!!!

[UG-T]

Get rom tune...just got mine back from enthalpy and 11.5 wot so fun!!!!!



Running factory hardware and less than factory boost does not require PCM tuning

[ShooterMcGavin]

New downpipe gasket on. Seems to run a little better but no change in a/f

[RussianSyndicate]

no, it should not!

[RussianSyndicate]

its ether going to be you MAF Sensor or your O2 sensor, that's if you don't have a problem with a vacuum leak or a semi-clogged injector or any other fuel related problem. I recommend you to unplug the O2 sensor or the MAF and then run the car around town. If it runs better, than I guess you pretty much found your problem. You can always clean you MAF sensor and your O2 sensor with special cleaners which is sold at autozone, it would not hurt to give them a try, unless you are completely broke.

[RussianSyndicate]

also, on some air fuel ratio sensors, you need to calibrate them. I will laugh my ass off if that turned out to be the problem you were having all along. lol

[ShooterMcGavin]

My Aem UEGO wideband does not require calibration. Wouldn't unplugging the MAF make it run really rich. I'll try testing the O2 again

[RussianSyndicate]

Yeah you are right, it could run pig rich but at least it would be a temporary solution.

[Crazyced]

Did you bother checking fuel pressure at WOT?

[ShooterMcGavin]

My fuel pressure gauge is in the bay. Pressure rises when reving but haven't checked it at WOT.

[Crazyced]

My fuel pressure gauge is in the bay. Pressure rises when reving but haven't checked it at WOT.
That's what you have to do. It will tell you what you need to know. Run a line and gauge to your windshield and test.

[htc.zenit]

Any solution found to this problem?
Kinda having the same issues here...

Engine runs perfectly fine, but Plugs are white :-/

[Kingtal0n]

Any solution found to this problem?
Kinda having the same issues here...

Engine runs perfectly fine, but Plugs are white :-/

lol, "help me! My plugs look perfect!"
http://i9.photobucket.com/albums/a90/kingtal0n/Kingtal0ns_240sx_2/right%20before%20I%20took%20them%20out%20forever%2 02-15-15_zps6goniuiy.jpg (http://s9.photobucket.com/user/kingtal0n/media/Kingtal0ns_240sx_2/right%20before%20I%20took%20them%20out%20forever%2 02-15-15_zps6goniuiy.jpg.html)

Its so turrible! Quick what should I do to make my engine run like shit like everybody else!

[cotbu]

Lol, my plugs look like that after idling, but after a pull they're tan. Then clean themselves again during idle.

Sent from a Highly Tuned Note 4.5!!!

[Crazyced]

Widebands are quite a bit cheaper then engines guys.

[89hatchman]

Are all your exhaust gaskets upstream of the o2 sensor good? Any gasket that's bad can throw off the reading.

I honestly wouldn't even worry with a stock set up. I've found it's pretty hard for the engine to hurt itself at stock boost.

[dorkidori_s13]

unplugging the MAF will put it into diagnostic mode, you wont be able to rev over 2500rpms.

if your 02 sensor is dead or not wired properly, it wont cause lean conditions at top end. the ECU goes into qusai-limp mode and dumps more fuel, so top end would be richer than usual.

i would HIGHLY advise you buying a consult port cable and getting your hands on a copy of NISTune. its one of the best diagnostic tools you can get for an OE ECU setup. unfortunately right now you cannot monitor your ECUs proper A/F ratios, injector duty cycles or timing. the stock injectors, ECU and MAF are terrible at dealing with bolt ons. my MAF and OE injectors are maxed out completely at 6500rpms on my S15 turbo with only 12psi of boost.

lean conditions CAN be caused by a leak BEFORE the turbo (after the MAF). what kind of tbolt clamps and couplers are you using? are you SURE youre not pulling air post MAF, pre turbo? unmetered air can cause REALLY annoying lean conditions (leaks post turbo will cause rich conditions btw)

PS: your plugs look fine for a pretty much stock SR.

[914Slide]

unplugging the MAF will put it into diagnostic mode, you wont be able to rev over 2500rpms.

if your 02 sensor is dead or not wired properly, it wont cause lean conditions at top end. the ECU goes into qusai-limp mode and dumps more fuel, so top end would be richer than usual.

i would HIGHLY advise you buying a consult port cable and getting your hands on a copy of NISTune. its one of the best diagnostic tools you can get for an OE ECU setup. unfortunately right now you cannot monitor your ECUs proper A/F ratios, injector duty cycles or timing. the stock injectors, ECU and MAF are terrible at dealing with bolt ons. my MAF and OE injectors are maxed out completely at 6500rpms on my S15 turbo with only 12psi of boost.

lean conditions CAN be caused by a leak BEFORE the turbo (after the MAF). what kind of tbolt clamps and couplers are you using? are you SURE youre not pulling air post MAF, pre turbo? unmetered air can cause REALLY annoying lean conditions (leaks post turbo will cause rich conditions btw)

PS: your plugs look fine for a pretty much stock SR.


I had a bad "leak" after the maf a breather can was put in line and it was sucking tons of unmeasured air now it wont go back to normal. My plugs look like this white as can be.