I have a 1996 Q45, when I freeze frame the mass air flow what should the perimeters read on my code reader? I hope some one can help.
thanksrichard
Mass air flow sensor
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maxnix
- Posts: 22627
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- Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45
Re: Mass air flow sensor (richard nemetz)
Not sure what you mean by "freeze frame the MAF sensor"
What are you trying to determine/measure?
Modified by maxnix at 6:47 PM 8/16/2007
What are you trying to determine/measure?
Modified by maxnix at 6:47 PM 8/16/2007
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: Mass air flow sensor (maxnix)
The 4.5 liter engine can consume 10 to 230 grams per second depending on rpm and load [throttle position].
Obviously air weight changes with temperature , barometric pressure and humidity: 1% per 11F. 3% per 1000' AMSL or per 1" HG [non corrected].
OBD1 ecu and 1996 OBD2 report the MAF flow in volts an exponentially rising 1.1> 4.4 volts
From a serious air flow persepective things don't get interesting until you begin to exceed 3500 rpms at WOT.
A 274 ci engine could injest 137 ci per revolution.
1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs. or 37 grams.
By definition peak torque rpm is the rpm point where the engine is most efficient in injeseting air where the most air per cylinder filling occurs...where the volumetric efficiency is highest.
Idle rpm is the least efficient rpm where the smallest amount of air is consumed per rpm.
Obviously air weight changes with temperature , barometric pressure and humidity: 1% per 11F. 3% per 1000' AMSL or per 1" HG [non corrected].
OBD1 ecu and 1996 OBD2 report the MAF flow in volts an exponentially rising 1.1> 4.4 volts
From a serious air flow persepective things don't get interesting until you begin to exceed 3500 rpms at WOT.
A 274 ci engine could injest 137 ci per revolution.
1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs. or 37 grams.
By definition peak torque rpm is the rpm point where the engine is most efficient in injeseting air where the most air per cylinder filling occurs...where the volumetric efficiency is highest.
Idle rpm is the least efficient rpm where the smallest amount of air is consumed per rpm.
Re: Mass air flow sensor (Q45tech)
Heheh, gawd, ya just' gotta love Dennis's posts, doncha?
Like a mainframe dump or sumpin.
Once again, thank you, Dennis, for being NICO's Master of the FSM and other esoteric data.
I hope that answer's Richard's question, heheh.
Like a mainframe dump or sumpin.
Once again, thank you, Dennis, for being NICO's Master of the FSM and other esoteric data.
I hope that answer's Richard's question, heheh.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Re: Mass air flow sensor (96Qowner)
If you cannot do all those gram/sec calcultions in your head [with a calculator] you really cannot gleen much from a MAF voltage or even grams per second report because you don't know what the correct value would be.
Even FSM only give broad +- 100% variations for idle and cruise and nothing for WOT at any rpm.
Thinking in exponential curves ........[C+ X^3.5] = MAF voltage......... is not normal for non math experts.
Even FSM only give broad +- 100% variations for idle and cruise and nothing for WOT at any rpm.
Thinking in exponential curves ........[C+ X^3.5] = MAF voltage......... is not normal for non math experts.