Lean idle when warm, checked basics

[di-devol]

Well, the car runs fantastic, good afr's after first start. Good afr's in boost, good afr's cruise.

This seems to be an intermittent problem.

So here we go:
On a cold start car runs rich(normal) 20 vac. Once warm occasionally, vac goes to 12-15 and runs so lean that the wideband maxes out full lean. Car "lopes" like a V-8.
Car occasionally run lean on VERY light throttle/Tip-in as well.
The thing that is getting me is would the car even run this lean? Idle is stable at 850rpms. Doesn't die, even running a un-reticulated BOV(runs rich when opened of course).

No vac leaks
No boost leaks(checked @30psi)
No exhaust leaks
02 sensor good
Maf is good
Injectors are brand new(and good)
CTS good
TPS good
Timing @15
Fuel pressure stock with nismo fpr


JWT tune
Sard 850's
GT2871r
Z32 maf
9:1 cp
Tomei 256 PonCams

Help if you can, the only thing that COULD be it I think is my MAF placement.
Could be a little too close:

http://i906.photobucket.com/albums/ac268/di-devol/IMG430.jpg

[Turbo Nismo]

If the car is only lean in iddle I guess it won't be a problem at all, unless if it leans out when boosting. My car is lean in iddle as well and in cruising also to safe up some gas, but when boosting it's perfect.

[di-devol]

I figured lean on no-load isn't the end of the world, and I don't mind the sound at all aha, but it just bugs me that shit aint right.

[di-devol]

Got it. Runs prefect at 14.5-15.1afrs at idle now.

Maf was to close to the turbo. LOL.

[di-devol]

Ok, Car has been waaaaaaaaaaaaaay better since moving the maf away from the turbo. Now it's doing it, BUT it's now intermittent. I'm going to try a different maf and see if that helps, maybe this one is on it's way out? Car drives perfect in boost, good in cruise, intermittent lean at tip-in.


Here is a video of it running good, then running lean, shows vac dropping when it runs lean.

WATCH YOUR EARS

http://s906.photobucket.com/albums/ac268/di-devol/?action=view&current=MOV019.mp4

Any thoughts?

[KiLLeR2001]

Judging by your temperature gauge needle, you are running a bit too hot. When my car reaches normal operating temp the needle is in between the 2nd and 3rd marker. I've noticed that when it starts creeping up past the 3rd marker the car starts running worse. I don't have an AFR gauge so I can't give you any numbers but in the video your needle is in between the 3rd and 4th marker, too hot IMO.

edit:

Here's my gauge waiting in line at Chik-fil-a... Idle is a little high I think my foot was resting on the throttle when I snapped this picture. Usually it idles around 850rpms.

http://tehl33tsite.com/240sxdd/black240/restoration/interior/IMAG0212.jpg

[di-devol]

^hmm, I never pay attention to that needle. I have a aftermarket gauge, shows about 160 in that video. Oil temp is about 160 as well, it's cold in the mornings here and with the oil cooler car runs on the cooler side.

[KiLLeR2001]

^hmm, I never pay attention to that needle. I have a aftermarket gauge, shows about 160 in that video. Oil temp is about 160 as well, it's cold in the mornings here and with the oil cooler car runs on the cooler side.

Ah I see, then you are fine. I'm guessing it could be the MAF then. Usually if its O2 or CTS related you'll run richer. Maybe over time the MAF being too close to the turbo damaged it beyond repair. I would try a known working one next.

[di-devol]

Thanks alot man, I hit the dyno at 4:30 today and I'm a little nervous aha. It's good in boost so I should be ok.

[di-devol]

Ok, well the dyno didn't go well at all. Started leaning out hard in higher rpms. I need to back up a bit to make sense of everything for those with the same problems.

First start the engine ran lean, all the time. I thought the stock fpr was bad and installed a nismo fpr.

That didn't change anything.

I found out the maf was too close to the turbo, moved it.

That changed the lean idle to a Intermittent issue.

On the dyno, car ran super lean the whole time, lean in boost, lean idle, tip-in/light throttle sucked. Gave up and went home.

I have a problem letting things go, so I start thinking again.

Put the stock fpr in.

No more lean idle.

Went for a drive, no lean issues at all, then the car dies and won't start. T start to trace wires and find the maf signal wire at the ecu had 1 thread connecting it. I find the ecu connector loose as well.

Drive home happy, get home and find a massive exhaust leak where the DP meets the cat. That explains the dyno's afr's reading leaner than my innovate WB.

Plugs before on the Right, plugs after the Dyno on the Left:
http://i906.photobucket.com/albums/ac268/di-devol/IMG451.jpg

The exhaust leak was making it seem leaner that it was, it was lean, just not THAT lean.

Going back to the dyno to verify it's all good.

New video of idle:
MOV020.mp4 video by di-devol - Photobucket (http://s906.photobucket.com/albums/ac268/di-devol/?action=view&current=MOV020.mp4)

[Walperstyle]

No offence to other guy regarding the temperature, but no two cars are the same. Don't worry about temperature unless its in the 3/4 or higher range. If you have a water cooled turbo/location of where you live/type of thermostat are just a few things that play into temperatures.

Sounds like you found the main problem though.

[di-devol]

^Nope, running lean again. There is something I'm missing, something I overlooked. I will find it.

[KiLLeR2001]

What is your fuel pressure at 850rpms idle with the vacuum unplugged?

[di-devol]

Stock at 3bar with the stock fpr, I set it to 3bar when I had the Nismo fpr installed. Now I'm thinking there is nothing wrong with the Nismo one though, it ran better at first. I'm moving something, something is changing after the fact to make it run lean.

[KiLLeR2001]

When you plug in the vacuum then what does it read?

[di-devol]

37-38psi with either fpr.

[KiLLeR2001]

What fuel pump? After driving your car, if you remove the gas cap do you get a surge of air out the tank? Any weird sounds coming from the fuel pump?

Exhaust manifold to turbo manifold, what method are you using to make sure the nuts don't shake loose causing an exhaust leak?

[di-devol]

Walbro 255, removing the gascap, there usually is a pshhh sound yes, Fuel pump sounds normal, Manifold to turbo, s15 gasket, studs, nuts tack wleded, with locking tabs ahaha(I had problems previously with that).

I did have an exhaust leak where the DP meets the Cat when I was on the dyno.
When we upped the fuel pressure to 85psi, when building boost it showed rich about 10afr, then as started to climb to about 15afr at 5500rpms. I know an exhaust leak would show lean, but I wouldn't think it would get worse exponentially(ish) like that(especially starting off rich).

[KiLLeR2001]

The fact that you're telling me it starts to act up after the car warms up leads me to believe this may have something to do with your fuel ventilation system. Do you have the vent blocked off? If not, your fuel check valve may have gone bad. If too much pressure builds up in the tank it can affect your pump. There shouldn't be a swoosh of air after removing your gas cap. My friend had an issue with this because he blocked off his gas tank vent. Killed one of his pumps like this. He got a new pump and unblocked his vent and he hasn't had a problem since.

[di-devol]

I don't know what's going on anymore lol, I need to start over step by step.

[rcdad123]

put a fuel pressure gauge on it and go for a drive. watch the fuel pressure gauge while driving. if the fuel pressure goes lower than 3 bars where you set it under load/boost, the fuel pump might be going bad.

[di-devol]

On the dyno, we upped the pressure to 85psi, at WOT, the pressure did go down to 65psi.. I don't know if a walbro could hold 85psi anyway lol. BUT, 65-psi it should still not cause it to run lean.

[di-devol]

Getting the logs from teh dyno runs I did, maybe it will shine some light on what's going on.

[di-devol]

Ok, wtf is going on? I replaced the wideband sensor with a new bosch replacement, old one that came out was covered in black soot. Calibrated it in open air with a reading of 22.1afr.

Idle is still lean, I have intermittent lean light throttle. RICH AS HELL in boost now, 9:1-10.5:1.

Oh, lord, sounds like a boost leak now.

[KiLLeR2001]

Sounds like a boost leak. I would start double checking everything. How's the intake manifold gaskets (upper and lower)?

[di-devol]

Sounds like a boost leak. I would start double checking everything. How's the intake manifold gaskets (upper and lower)?

I'll check them.
I'll boost leak test when I get off work, I appreciate the help from everyone!

[di-devol]

Nope, no boost leaks. When it does idle correctly vacuum is at 19-20. Light throttle seems good right now, boost is good as well. I just dunno.

[di-devol]

Only lean at idle intermittently, light throttle seems to hesitate rarely. Boost seems very good, starts of rich at 9.5 then hits 10.8 and holds there.

When it does idle lean, it idles at 22.1 for about 10 secs then richens up to 14-15 for about 15 secs, then goes back to lean.

Why the hell is it intermittent?

[KiLLeR2001]

I'm starting to think something with the tune at this point.

[di-devol]

I'm starting to think something with the tune at this point.

If it was the tune, it wouldn't run great half the time. If it was running lean from the tune, it would never run great, there are times when it bloody perfect. Something is up.

I have to find it.

[waxball88]

I have the same issue man. I'm KA-T though. Idles fine on first start up/after sitting. Once its warmed up/start driving most often boosting and i come to a stop it will slowly lean out til max, then starts with the shitty idle. Or it will try and stumble, sometimes die if i dont blip the throttle.
Other times it will sit and idle like a fucking champ.
After i boost leak tested/fixed my car, response was better but the lean issue was more pronounced. Hesitation on tip-in throttle, runs fine if i'm dogging it (although rich) which implies boost/vac leaks.
I'm about to go back outside and replace more lines and see if anything can rid me of this forsaken problem.

[rps_jrdn]

I'm starting to think something with the tune at this point.

i agree.... 9.5 10.8 is quite rich when boost hits.... should be at 11.6-12.1... i'm surprised your not shooting black smoke out the tail pipe from running that rich on full boost.

perhaps it maybe the idle air control valve too thats causing the lean idle...

[KiLLeR2001]

Try another MAF that is known to be working correctly... But before that check the MAF wiring ALL the way through. Make sure the signal wire is shielded so theres no interference.

[di-devol]

i agree.... 9.5 10.8 is quite rich when boost hits.... should be at 11.6-12.1... i'm surprised your not shooting black smoke out the tail pipe from running that rich on full boost.
perhaps it maybe the idle air control valve too thats causing the lean idle...

I'm struggling to think it's the tune, I figured if it was the tune it would NOT be intermittent, ya know?
lol, I try to look for smoke but there is always too much tire smoke. I can't hook up at full boost. I unplugged the IACV, idle just became more rough. The idle screw on the IACV works correctly as well.

Try another MAF that is known to be working correctly... But before that check the MAF wiring ALL the way through. Make sure the signal wire is shielded so theres no interference.

I am going to try a known working MAF on Thursday, I can trace wires when I get home tonight.

Thanks guys!

[ultimateirving]

did u completely reset your innovate unit when installing the new sensor. read the manual from innovate and make sure to completely reset the unit.

[towlie]

I may have missed it, what exactly are your afr readings at idle?

Did you try calling jwt and explaining your situation? Maybe they could give you some pointers

[di-devol]

did u completely reset your innovate unit when installing the new sensor. read the manual from innovate and make sure to completely reset the unit.

Yup, but I can try it again just to be sure.
I may have missed it, what exactly are your afr readings at idle?

Did you try calling jwt and explaining your situation? Maybe they could give you some pointers

Watch the videos man. 22.1afr

I've been in contact with JWT, being intermittent, it something with my set-up.

[towlie]

Yeah, what the fuck?

Try that MAF and see what happens. I have a brand new stack w/b we can hook up to make sure your innovate is working correctly if u need to. I'm lost otherwise lol

[di-devol]

That would be awesome if it comes to that man lol.

[towlie]

No problem u have my number. I just got it wired up today, My car idles at a 13.9-14.1 @ 850 so it's dead on

[di-devol]

Alright, I re-wired the maf last night, and for the hell of it I re-wired the injectors. I went for a drive to the airport to pick up my wife. Big difference!

No hesitation on light throttle whatsoever, but boost was 7-8 afr lol. I replaced the new bosch sensor with another, did a sensor calibration, heater calibration and cleared the settings on the controller.

On the way to work this morning, light throttle is fantastic, boost is 11.2-11.5!!

Still lean at idle, though it's different. Coming to a stop, it runs rich for a sec(open BOV) then idles lean for 1-2 secs(18-19afr) then settle to 14-15 for about 30 sec then climb back up to 17-18, sit there for a bit then lean out off the chart at 21.7. If I blip the throttle, it does the same cycle again. Guessing the IACV for that issue.

Over-all a lot better.

[KiLLeR2001]

Now that you've fixed the wiring try another MAF!!!

[di-devol]

I am!

lol, thanks alot man.

[di-devol]

Tried a different maf, no dice.

[KiLLeR2001]

Redtop SR? Skinny O2 sensor? How does AFR change if you unplug it?

[di-devol]

Red top, skinny O2. Trying that next, unplugging it does not change anything. My JWT tune states O2 feed back is turned on. Always thought that caused a rich condition though?

[KiLLeR2001]

Red top, skinny O2. Trying that next, unplugging it does not change anything. My JWT tune states O2 feed back is turned on. Always thought that caused a rich condition though?

Mostly, but if you unplug it, it should definitely get richer. If nothing changes then it's possible bad O2 wiring or the O2 sensor itself.

[rps_jrdn]

Red top, skinny O2. Trying that next, unplugging it does not change anything. My JWT tune states O2 feed back is turned on. Always thought that caused a rich condition though?

nah O2 feedback on is leaner... O2 feedback off is rich.... there fore unplugging the O2 should make it richer.

[di-devol]

Back from the dead. I could never figure out the lean idle. Car drifted fine, as always it's good in boost. I developed a really bad rich condition in boost over the season though. So I re-did alot of stuff.

Installed a new harness
New o2 sensor
Injectors are not leaking
Maf is good
No boost leak, no vac leak.
Moved the maf out more.
No exhaust leaks.
No change when unplugging the O2 sensor. Wiring checks out though.

Car runs perfect when cold. Well, it runs how it should when it's warm, when cold. Warm up enrichment table makes it run about 14-15 arfs when COLD.

Once warmed up, it leans out to 18-19 afrs. Still runs but makes a lope sound, kinda like a v-8. car is still good in boost.

I've done everything, I'm starting to think it's the JWT tune :/

[codyace]

To have it 'run away' sort to speak is odd, and would be something (IMO) car/harness related that is causing the ECU adjust the fuel. The tune itself isn't going to be setup to just 'keep going lean', something obviously will be telling it to do so.

[waxball88]

Ended up sending my ECU back to Enthalpy, new ecu runs a little rich at idle, no more stalling on decel, or leaning out condition

[codyace]

Ended up sending my ECU back to Enthalpy, new ecu runs a little rich at idle, no more stalling on decel, or leaning out condition

The only reason your car would ever stall on decel is due to unrecirculated BOV. Sounds like the 'fix' is masking an underlying issue.

[di-devol]

It's really weird, cold start is 14-15afr, but idles great at 19-20 vac, once warming up the vac will drop to 15 and lean out. If I try to hold it up at 3k rpms it will drop down to 2k lean out and start to what sounds like a mis-fire.

Yesterday, we tried another o2 sensor, another cts sensor.

I just talked to Ben at JWT, gonna try and move the maf farther away as a test. Also picking up the consult stuff and some software to see what's going on.

[di-devol]

Well i moved the maf ridiculously far away from the turbo with no change. I noticed in boost i started to throw black smoke. Checked the fuel pressure and was around 50psi with no vacuum. Set that back and now no more smoke.

Working on getting a consult cable to use Nissan data scan to see what we can find.

[di-devol]

I've been searching forever on this topic and found numerous people with the same problem one time or another, but never with an answer. So here is an update.

I installed stock ecu, injectors and maf, car ran perfect. cold start was 10ish warming up to 13-14 when warm. Cam sounding lope is gone, I can hold the rpms with good afr's.

Putting the JWT ecu, z32 maf, and the sards back on, car leans out to 21-22 and just stays there. I'm out of stuff to check, and since it ran good on stock stuff, I have to say it's the tune :/

The fuel pressure is odd. With a stock fpr fuel pressure was 50ish, installed a nismo fpr put it down to stock. Now, the car is lean in boost as well at 13-14. So with stock fuel pressure the car is undrivable now.

Just waiting to hear from JWT now.

[waxball88]

The only reason your car would ever stall on decel is due to unrecirculated BOV. Sounds like the 'fix' is masking an underlying issue.

It's not impossible, but Martin had me go through his whole bag of tricks before sending it back. I can boost leak to 30 psi and don't hear a peep, all note worth vac lines have been converted to pushlok an. I tried 4 different knock sensors/sub harness combos to no avail. I was running a shitty greddy knock off bov but I tried simply running no bov. I have an apexi bov now, and plans to make it to Martin to have him put his hands on the car in person
Also took apart and cleaned 2 iacvs(told these can cause stalling) Also plan on moving to blow through soon.

[towlie]

Weak, sounds like u narrowed down the problem tho

[di-devol]

I dunno yet. I'm checking everything for the 11th time.

[di-devol]

Updating just for that fact that no one updates.

We had the car tuned on AEM ems, lean issues persisted.

Either the engine hated life, or it was cursed.

Going to blame wiring, bad grounds, something fishy. Motor blew, so end of story.

[towlie]

Looks like you lost then.

:D

[bmxer882x]

Revival time!

All summer I have been dealing with this exact same issue. Except my wideband only reads to 18 so I'm not sure how lean I really am at idle. It runs great until warmed up then goes lean on idle and cruising. Boost and normal driving is great. Holds 12.1 at wot.

Things I have done
Checked grounds for z32 maf
Tps voltage at .45
New cts
Fuel pump hotwire
New fuel filter
Timing at 15
Boost leak test held to 25 where I stopped
No vac leaks found with carb cleaner
New bov (synapse dv)
New 02

Any advice would be appreciated. Going to try to get another z32 maf to borrow soon. It's ran through the stock Sr intake pipe.

One thing I have noticed is my maf voltage stays at 1.32v on idle and will randomly drop to 1.08 for a split second then raise back to 1.32.