Another insufferable maf code post

Ghostvette · 06-15-2017, 09:40 AM

Quote:

Originally Posted by Ommateal

Had codes done by a very nice scanner, It looks like since I changed the Mafs those have not shown back up, the Major codes I got this time were Lean Bank codes 1 and 2

P0171 Lean Bank 1 - This was stored when I ran the codes
P0174 Lean Bank 2 - This showed up after a clear -

Then my car died After letting it get hot for a while, We took a break, I went to leave, and it sputtered and stalled until sufficient time passed it cooled and was able to start.

We are possibly leaning twords a fuel issue now that maf codes are gone.

Failing pump?

Just to be thorough and for knowledge in the post, Here is a full list of codes that first pulled some may be redundant and coincidence from messing with stuff, most are my steering lock (pulled fuse) I think.

B2014 - Chain of Steering lock BCM
B2562 - Low Voltage
B2607 - Lock Relay
B2609 - Lock Status
B260A - Ignition Relay
B26E8 - Clutch Interlock Switch
B2109 - Lock relay off

Engine stuff

P0300 - random multiple Misfires
P0171 - Too lean Bank 1
Po174 - Too lean Bank 2

Thats all I got this time around.

Quote:

Originally Posted by Ommateal

No too sure about that battery exactly but I have used two different batteries so far since the issue has happened , they show consistent voltage. And no change of symptoms improving between either battery.

And Which relearn do you speak of exactly? Idle relearn?
Ala: 2003-2011 Nissan 350Z - 370Z Idle Air Volume Learning Procedure | Nissanhelp.com

Also lslightly off topic, but SouthArk or anyone, do you know What shape fuel Strainer we have? Is it the Moon/Half circle shape? Or square bag shape?

A lean condition is caused by 2 primary things, air & fuel. If the MAF sensor doesn't read the air flow correctly, the ECM compensates by altering the injector duty cycle (length of time open and size of aperture). Some common problems that are starting to appear on 09-11 models are the fuel pump 'hats' breaking off and the pump is laying in the bottom of the gas tank. Phunk (CJM) has a fix for that.

The pictures I've seen in the parts catalog from Nissan is that the strainer is a rectangular 'sock'. But they could be using a 'generic' picture.

Wilson2608 · 06-15-2017, 10:19 AM

Quote:

Originally Posted by Ghostvette

A lean condition is caused by 2 primary things, air & fuel. If the MAF sensor doesn't read the air flow correctly, the ECM compensates by altering the injector duty cycle (length of time open and size of aperture). Some common problems that are starting to appear on 09-11 models are the fuel pump 'hats' breaking off and the pump is laying in the bottom of the gas tank. Phunk (CJM) has a fix for that.

The pictures I've seen in the parts catalog from Nissan is that the strainer is a rectangular 'sock'. But they could be using a 'generic' picture.

My fuel pump hat broke off as well. It is very possible it has happened to OP as well, however I never had any of the issues OP posted about. I just had a messed up gas gauge but none the less still check it out

Ommateal · 06-15-2017, 03:45 PM

Quote:

Originally Posted by Wilson2608

My fuel pump hat broke off as well. It is very possible it has happened to OP as well, however I never had any of the issues OP posted about. I just had a messed up gas gauge but none the less still check it out

Thanks Both of you, can I visually see if it's broken easily after opening the fuel compartment behind the seats? My fuel Gauge hasn't shown any issues as far as Iv'e noticed.

I did The full CPU reset relearn procedures - not really any improvement.

Would any of this result in my symptoms of being driveable (but less power and a small stuter at 3krpm) Untill it gets hot and sputter/stalls (most common AFTER turning the car off for a few mins then trying to restart - usually fails to fully start till its cool again)

Wilson2608 · 06-15-2017, 07:34 PM

Yes once you take off all the bs to get to the fuel tank you'll see a white plastic piece. Just unscrew it and pull it out(this is the hat we're referring to it contains you fuel pump and some sensors). You will be able to see if it's broken, however since you said you haven't had any issues with your gas gauge I doubt it's the problem.

Wilson2608 · 06-15-2017, 07:42 PM

I would first start with getting a fuel pressure gauge to be sure you don't have a fuel pump issue. The initial codes were MAF codes so if your fuel is good I'd go back to the MAF sensors. I know you said you replaced them with brand new but cheap ones, were these oem maf sensors you replaced them with?

SouthArk370Z · 06-15-2017, 07:46 PM

Quote:

Originally Posted by Ommateal

... Would any of this result in my symptoms of being driveable (but less power and a small stuter at 3krpm) Untill it gets hot and sputter/stalls (most common AFTER turning the car off for a few mins then trying to restart - usually fails to fully start till its cool again)

If the engine is running lean (as per codes you gave above), there are a lot of things that could be the problem - vacuum leak, bad injector, weak fuel pump, bad sensor, faulty ECM, high resistance wiring, etc. Monitoring some of the engine params might give you a hint.

Ommateal · 06-19-2017, 11:56 AM

Almost thought it was fixed after a pretty long drive - But nope lol. Did an oil change and threw some injector cleaner in it just for the hell of it. It is running slightly better, but The issues are present and just feel more random though less impactfull....so thats a good thing I guess haha.

I will try to see if I can find a cheap way to test the fuel pressure. So far all I'm seeing is a gauge thats 50bucks. For that price I can basically just buy a new Walbro Pump.

Not sure what else to do other then take it to the dealer shop, and I'm deff not sure how I feel about my local nissan dealer... as far as skill level for problems with the car especially with it being out of warranty.

Ommateal · 07-02-2017, 04:06 PM

Any ideas on a way to test fuel pressure without buying the 50$ tester? Or should I just say F it and buy a pump cuz its the same price basically O.o ?

Ommateal · 07-07-2017, 05:46 PM

****Update****

Just got off the phone with the dealership - They said they think it's the Air fuel Sensor On the EXHAUST MANIFOLD, passenger side. Can anyone point me to exactly what part this is.

Someone from the dealer read me this part number 226931na0a is this correct?

This it in the pic and heres the one I might buy.

Ommateal · 07-11-2017, 09:30 AM

****UPDATE#2****

Replaced the AF sensor Bank 1 with a Denso.

Car is running much better but still not totally fixed.

It's pulling harder and as of right now almost no stumble - still a small stumble seldom at 3.5k rpm but its mostly gone.

After car is hot (200+ degrees) and turned off for a little bit apon restart it is still sputtering but not as bad.

I can't keep nickle and dime parts into this car... -.- Any repair suggestions? Should I replace the driver side AF as well?

Here is a pic of the recommended work from nissan - His tests ONLY showed Bank 1 issue af though recommends changing both banks.

Z_ealot · 07-13-2017, 01:30 AM

Quote:

Originally Posted by Ommateal

****UPDATE#2****

Replaced the AF sensor Bank 1 with a Denso.

Car is running much better but still not totally fixed.

It's pulling harder and as of right now almost no stumble - still a small stumble seldom at 3.5k rpm but its mostly gone.

After car is hot (200+ degrees) and turned off for a little bit apon restart it is still sputtering but not as bad.

I can't keep nickle and dime parts into this car... -.- Any repair suggestions? Should I replace the driver side AF as well?

Here is a pic of the recommended work from nissan - His tests ONLY showed Bank 1 issue af though recommends changing both banks.

just an update....after I changed out my pcv valves I now see my fuel trims in opposite positions at startup. before changing out the pcv valves on startup my LTFT would be at -10.94% with STFT trending towards +9%. once warm with the old pcv valves my LTFT would stay stuck at -10.94% with STFT at around +3% or close to 0%, when I would snap the throttle open LTFT would stay pinned at -10.94%. now with new PCV valves on startup my LTFT is now at +9% and STFT is at a -10% until warm up when LTFT seems to settle at around -8% and STFT seems to settle around 0%, interesting to note however is now when I snap the throttle open all fuel trims line up at 0% or close to it and go back to the previous figures when let back down to idle. not to jump to any conclusions, but to me at least the old PCV valves seem to have been the culprit when it came to the fuel trims seeing as everything is now lining up with the new PCV valves. oh and car now idles smoothly without the stumbles and drops in RPM I was seeing before.

Ommateal · 07-18-2017, 11:55 AM

****UPDATE#3****

Installed an oil cooler - can confirm it still has the same issues but now I can rule out that having 200+ degree oil temp has nothing to do with it.

They said i'm running a constant 30psi, but isn't that TOO low? The fsm says 51psi @ idle. And WHo knows how long he tested or if he tested at load or during the issue.

Issue with my Fuel pressure regulator maybe?

Is there anyone in North East Ohio area that can truly figure out this issue... ugh. I'm going crazy.

Ommateal · 07-22-2017, 02:17 PM

*** update # who cares...***

Nissan agreed that 30psi was too low and recommends replacing the fuel pressure regulator.

...can't seem to find them for sale anywhere.

From dream car to nightmare.

Z_ealot · 07-23-2017, 10:01 AM

Quote:

Originally Posted by Ommateal

*** update # who cares...***

Nissan agreed that 30psi was too low and recommends replacing the fuel pressure regulator.

...can't seem to find them for sale anywhere.

From dream car to nightmare.

Maybe this is the part they are referring to? Seems to come up a lot when you search for fuel pressure regulator.

https://www.z1motorsports.com/fuel-d...hr-p-9194.html

Edit: looks like the fuel pressure regulator is built into the fuel pump assembly so i guess time for a new fuel pump?

Ommateal · 07-24-2017, 09:31 AM

Quote:

Originally Posted by Z_ealot

Maybe this is the part they are referring to? Seems to come up a lot when you search for fuel pressure regulator.

https://www.z1motorsports.com/fuel-d...hr-p-9194.html

Edit: looks like the fuel pressure regulator is built into the fuel pump assembly so i guess time for a new fuel pump?

Thanks Z_ealot - Yeah this is just a pulse damper (they help regulate the pressure at the rails) there should be 2 of them and they are right in the engine bay one is seen easily near the left intake. They are cheap and I might replace just to see if it helps, but as far as nissan dealer is concerned they said im getting 30psi, which would point more to the pump/basket/regulator/lines as far as I know. . . THis issue is driving me nuts and obv Nissan is only shooting answers in the dark - feel like they cant really diagnose it correctly.

06-15-2017, 07:34 PM	#19 (permalink)
Wilson2608 Enthusiast Member Join Date: Dec 2014 Location: Nashville Posts: 301 Drives: Nissan 370Z Sport Rep Power: 11	Yes once you take off all the bs to get to the fuel tank you'll see a white plastic piece. Just unscrew it and pull it out(this is the hat we're referring to it contains you fuel pump and some sensors). You will be able to see if it's broken, however since you said you haven't had any issues with your gas gauge I doubt it's the problem. __________________ Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports.

06-15-2017, 07:42 PM	#20 (permalink)
Wilson2608 Enthusiast Member Join Date: Dec 2014 Location: Nashville Posts: 301 Drives: Nissan 370Z Sport Rep Power: 11	I would first start with getting a fuel pressure gauge to be sure you don't have a fuel pump issue. The initial codes were MAF codes so if your fuel is good I'd go back to the MAF sensors. I know you said you replaced them with brand new but cheap ones, were these oem maf sensors you replaced them with? SouthArk370Z and Ommateal like this. __________________ Stillen G3, z1 Intake Manifold, Stillen Headers, Z1 HFC's, Stillen Catback. 330whp 267 ft- lbs tuned at Z1 motorsports. Last edited by Wilson2608; 06-15-2017 at 07:46 PM.

06-19-2017, 11:56 AM	#22 (permalink)
Ommateal Base Member Join Date: Oct 2015 Location: Dover, Ohio. Age: 37 Posts: 209 Drives: 2010 370z sport 6m Rep Power: 10	Almost thought it was fixed after a pretty long drive - But nope lol. Did an oil change and threw some injector cleaner in it just for the hell of it. It is running slightly better, but The issues are present and just feel more random though less impactfull....so thats a good thing I guess haha. I will try to see if I can find a cheap way to test the fuel pressure. So far all I'm seeing is a gauge thats 50bucks. For that price I can basically just buy a new Walbro Pump. Not sure what else to do other then take it to the dealer shop, and I'm deff not sure how I feel about my local nissan dealer... as far as skill level for problems with the car especially with it being out of warranty. __________________ Red 370z Sport 6m Mods: Stillen 25 row Race Oil cooler\|FIXED ESCL\|Muffler delete\|TEIN Springs\|Tint\|Varrstoen ES2 Rims\|NRG Stealth Knob\|Kenwood touchscreen\|

07-02-2017, 04:06 PM	#23 (permalink)
Ommateal Base Member Join Date: Oct 2015 Location: Dover, Ohio. Age: 37 Posts: 209 Drives: 2010 370z sport 6m Rep Power: 10	Any ideas on a way to test fuel pressure without buying the 50$ tester? Or should I just say F it and buy a pump cuz its the same price basically O.o ? __________________ Red 370z Sport 6m Mods: Stillen 25 row Race Oil cooler\|FIXED ESCL\|Muffler delete\|TEIN Springs\|Tint\|Varrstoen ES2 Rims\|NRG Stealth Knob\|Kenwood touchscreen\|

07-18-2017, 11:55 AM	#27 (permalink)
Ommateal Base Member Join Date: Oct 2015 Location: Dover, Ohio. Age: 37 Posts: 209 Drives: 2010 370z sport 6m Rep Power: 10	**UPDATE#3** Installed an oil cooler - can confirm it still has the same issues but now I can rule out that having 200+ degree oil temp has nothing to do with it. They said i'm running a constant 30psi, but isn't that TOO low? The fsm says 51psi @ idle. And WHo knows how long he tested or if he tested at load or during the issue. Issue with my Fuel pressure regulator maybe? Is there anyone in North East Ohio area that can truly figure out this issue... ugh. I'm going crazy. __________________ Red 370z Sport 6m Mods: Stillen 25 row Race Oil cooler\|FIXED ESCL\|Muffler delete\|TEIN Springs\|Tint\|Varrstoen ES2 Rims\|NRG Stealth Knob\|Kenwood touchscreen\|

07-22-2017, 02:17 PM	#28 (permalink)
Ommateal Base Member Join Date: Oct 2015 Location: Dover, Ohio. Age: 37 Posts: 209 Drives: 2010 370z sport 6m Rep Power: 10	* update # who cares...* Nissan agreed that 30psi was too low and recommends replacing the fuel pressure regulator. ...can't seem to find them for sale anywhere. From dream car to nightmare. __________________ Red 370z Sport 6m Mods: Stillen 25 row Race Oil cooler\|FIXED ESCL\|Muffler delete\|TEIN Springs\|Tint\|Varrstoen ES2 Rims\|NRG Stealth Knob\|Kenwood touchscreen\|

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