question about maf sensors

phunk · 07-08-2017, 07:11 PM

Quote:

Originally Posted by Z_ealot

Shouldnt there be no oil in the pcv hose though if the valve is functioning correctly?

Oil coming through the PCV and into the intake is completely normal. The PCV system does not discriminate oil and vapor from clean air.

Z_ealot · 07-08-2017, 07:21 PM

Quote:

Originally Posted by phunk

Oil coming through the PCV and into the intake is completely normal. The PCV system does not discriminate oil and vapor from clean air.

What would you suggest is causing the lean condition then? Fyi LTFT is considtently over negative 10% with STFT going up to over 15%

phunk · 07-08-2017, 07:31 PM

if long term and short term are opposite but the final product is a satisfactory AF, I'd figure perhaps varying blends of ethanol in the fuel just making the fuel trims do their job.

Z_ealot · 07-08-2017, 07:38 PM

Quote:

Originally Posted by phunk

if long term and short term are opposite but the final product is a satisfactory AF, I'd figure perhaps varying blends of ethanol in the fuel just making the fuel trims do their job.

So what about the hesitation and stumbling at idle?

phunk · 07-08-2017, 07:48 PM

Quote:

Originally Posted by Z_ealot

So what about the hesitation and stumbling at idle?

I haven't seen that yet so cannot really comment. Sounds normal in the PCV video though.

jchammond · 07-08-2017, 08:42 PM

Someone is selling a nice pair of catch can's for around 3k on here.

Z_ealot · 07-08-2017, 09:46 PM

Quote:

Originally Posted by jchammond

Someone is selling a nice pair of catch can's for around 3k on here.

Are they made of gold? lol

jchammond · 07-08-2017, 09:50 PM

Quote:

Originally Posted by Z_ealot

Are they made of gold? lol

Not Sure-It's Top Secret Brand.

jchammond · 07-09-2017, 05:42 AM

Would not be bad to install a pair;as long as they are functional.
over time the sucked oil (blow by from engine) will gum up in the combustion chamber.
unsure your milage on engine or fuel type/quality being used,,,but i've seen lot's more harm than good from the 10% ethanol blended fuel's.
Ethanol fuel (e-85 etc.) work's great when all supporting components are in place for it & the car is tuned for it.....unsure the shelf life or how long you would want it sitting in your tank;as conventional 10% ethanol gas will begin separating as soon as 1 month (+ or - a bit).
I pay more; but continue my ethanol free93 fuel without problems.
The factory fuel system on these car's don't have a return fuel line-as there was one occasion that i had a stumbling under hard load & not accelerating,,,i checked all known connection's from electrical to vacuum & then removed fuel line to rail & purged out some fuel....thinking maybe got some bad gas-but was all clean.
Car ran perfect ever since.
There are way more skilled & knowledgable people on here that have valid input's.
A little more maintenance is required,but catch can's may be a start to prevent gumming up inside the intake system.
Also a failing or clogged fuel system can cause it to go lean & even show mis-fires.

Z_ealot · 07-10-2017, 08:10 AM

Quote:

Originally Posted by jchammond

Would not be bad to install a pair;as long as they are functional.
over time the sucked oil (blow by from engine) will gum up in the combustion chamber.
unsure your milage on engine or fuel type/quality being used,,,but i've seen lot's more harm than good from the 10% ethanol blended fuel's.
Ethanol fuel (e-85 etc.) work's great when all supporting components are in place for it & the car is tuned for it.....unsure the shelf life or how long you would want it sitting in your tank;as conventional 10% ethanol gas will begin separating as soon as 1 month (+ or - a bit).
I pay more; but continue my ethanol free93 fuel without problems.
The factory fuel system on these car's don't have a return fuel line-as there was one occasion that i had a stumbling under hard load & not accelerating,,,i checked all known connection's from electrical to vacuum & then removed fuel line to rail & purged out some fuel....thinking maybe got some bad gas-but was all clean.
Car ran perfect ever since.
There are way more skilled & knowledgable people on here that have valid input's.
A little more maintenance is required,but catch can's may be a start to prevent gumming up inside the intake system.
Also a failing or clogged fuel system can cause it to go lean & even show mis-fires.

Gonna pick up a couple of pcv valves today just as preventative maintenance. I do recall when i had the upper intake manifold off the the chambers on the lower intake manifold leading to bank 2 had quite a bit of oil built up on them while oddly enough the chambers leading to bank 1 barely had any oil build up at all. Not sure if that indicates anything, but still the pcv valves on this car are the originals and the engine has close to 157,000 miles on it. As a side note i have run a couple of cans of fuel system cleaner through the tank before just on the off chance that there was a clog somewhere in the lines back when this all started, but didnt seem to help much

Z_ealot · 07-10-2017, 10:14 PM

Quote:

Originally Posted by phunk

I haven't seen that yet so cannot really comment. Sounds normal in the PCV video though.

does this sound normal to you....

Z_ealot · 07-10-2017, 10:53 PM

Quote:

Originally Posted by phunk

Yes? Who cares what it sounds like when you shake it? See the service manual for details on how to test it. You originally asked if its supposed to flow under vacuum at idle, and the answer is yes. Thats exactly what its supposed to do. I also showed you a screenshot from the service manual stating the same thing. As for your video, both the new and the old one sound identical... so I am not sure what its supposed to prove. But I have some valves here off a perfectly running Z and they dont make that noise at all. So you tell me what sound is normal.

I dunno, but the fact I had to shake the old one pretty vigorously in order to get it to rattle like that says a lot to me compared to the new one which I barely had to put any force into In order for it to rattle like that. in any case I would rather have new pcv valves than ones with almost 157,000 miles on them and no history on the car of whether the oil was changed on a timely basis to prevent the valves from gumming up in the first place if they ever had.

phunk · 07-10-2017, 10:54 PM

Quote:

Originally Posted by Z_ealot

I dunno, but the fact I had to shake the old one pretty vigorously in order to get it to rattle like that says a lot to me compared to the new one which I barely had to put any force into In order for it to rattle like that. in any case I would rather have new pcv valves than ones with almost 157,000 miles on them and no history on the car of whether the oil was changed on a timely basis to prevent the valves from gumming up in the first place if they ever had.

SouthArk370Z · 07-10-2017, 11:07 PM

Quote:

Originally Posted by Z_ealot

... I would rather have new pcv valves than ones with almost 157,000 miles on them and no history on the car of whether the oil was changed on a timely basis to prevent the valves from gumming up in the first place if they ever had.

At 30K miles, I might just spray some carb cleaner through them. At almost 160K miles, it's time to replace them.

Ommateal · 07-11-2017, 08:45 AM

Quote:

Originally Posted by Z_ealot

So what about the hesitation and stumbling at idle?

Welcome to the 'messed up, hesitant, impossible to diagnose, Z club"

You can check out my post as well... Another insufferable maf code post

07-08-2017, 07:31 PM	#33 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,654 Drives: 370 Rep Power: 944523	if long term and short term are opposite but the final product is a satisfactory AF, I'd figure perhaps varying blends of ethanol in the fuel just making the fuel trims do their job. Z_ealot likes this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

07-08-2017, 08:42 PM	#36 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 57 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684394	Someone is selling a nice pair of catch can's for around 3k on here. Z_ealot likes this. __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

07-09-2017, 05:42 AM	#39 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 57 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684394	Would not be bad to install a pair;as long as they are functional. over time the sucked oil (blow by from engine) will gum up in the combustion chamber. unsure your milage on engine or fuel type/quality being used,,,but i've seen lot's more harm than good from the 10% ethanol blended fuel's. Ethanol fuel (e-85 etc.) work's great when all supporting components are in place for it & the car is tuned for it.....unsure the shelf life or how long you would want it sitting in your tank;as conventional 10% ethanol gas will begin separating as soon as 1 month (+ or - a bit). I pay more; but continue my ethanol free93 fuel without problems. The factory fuel system on these car's don't have a return fuel line-as there was one occasion that i had a stumbling under hard load & not accelerating,,,i checked all known connection's from electrical to vacuum & then removed fuel line to rail & purged out some fuel....thinking maybe got some bad gas-but was all clean. Car ran perfect ever since. There are way more skilled & knowledgable people on here that have valid input's. A little more maintenance is required,but catch can's may be a start to prevent gumming up inside the intake system. Also a failing or clogged fuel system can cause it to go lean & even show mis-fires. __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

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