Motor Vehicle Maintenance & Repair Stack Exchange
Motor Vehicle Maintenance & Repair Stack Exchange

Questions tagged [maf]

Anything related to MAF (Mass Air Flow) sensors.

Mass Air Flow corresponds to a measurement of the mass air flow rate entering a fuel-injected internal combustion engine measured by the MAF sensor. This sensor precedes the intake manifold/throttle body and typically follows the air snorkel just after the air filter. https://en.wikipedia.org/wiki/Mass_flow_sensor

61 questions
17
votes
3 answers

What is the difference between a MAP and a MAF sensor

Generally a car uses either MAP or MAF to determine the air flow index the engine is getting and that older cars used to have MAP and newer ones often use MAF and cars like the Mitsubishi EVO uses both of them. I would like to know how they operate…
Shobin P
  • 8,966
  • 14
  • 41
  • 74
12
votes
1 answer

How is it advantageous for fuel management to detect negative mass air flow?

Here is the flow-voltage mapping for the Bosch sensor utilized by my E39 M5. I find it curious that readings below 0.9 V correspond to negative flows. Questions Is it possible that air can flow the other way (maybe through some sort of pressure…
Zaid
  • 39,276
  • 50
  • 151
  • 294
10
votes
3 answers

Mass Air Flow Expected Values

I have a 2002 Audi A4 Quattro 3.0. I have a Vagcom USB cable and I am trying to diagnose the MAF sensor. I had a friend get some readings from an OBD2 scanner, which indicated that both precat O2 sensors (passenger side and driver side) had negative…
SSH This
  • 237
  • 1
  • 4
  • 10
10
votes
2 answers

Power loss in truck - triage options?

I've asked at least one question about my specific situation earlier, but at this point, I'm looking for information on how to operate in triage mode, my primary goal is to get my truck working well enough to run without issue for two weeks, because…
Paul
  • 509
  • 3
  • 6
  • 14
8
votes
1 answer

Anyone have experience with a faulty fuel press? Regulator?

I've been dealing with a car that starts and then suddenly dies. I replaced the MAF (Mass Air Flow) sensor with a new one, and now it stays on until I press the gas pedal. The throttle body is clean. Before the car acted up, the spark plugs had a…
Spenser Hicks
  • 81
  • 2
8
votes
3 answers

Calculating MPG from MAP sensor (or converting MAP data to MAF data)

My 2002 Honda Accord V6 has a Manifold Absolute Pressure sensor (MAP). I understand that this sensor gives out information in pressure units (psi or equivalent). After doing a bit of research, I realized that my car does not have a Mass Air Flow…
NewGradDev
  • 181
  • 1
  • 2
7
votes
4 answers

Sputtering while driving & idling

[My car: 2004 Mazda 3] So, my wife came home from running some errands and told me the check-engine light was on and that the car was sputtering and felt like it was going to stall while stopped at stop lights. I went to check it out, maybe 5…
Trev
  • 255
  • 2
  • 4
  • 9
7
votes
1 answer

Should you replace the MAF sensor housing when replacing the MAF sensor itself?

When I search for a MAF (mass air flow) sensor on a parts website, I see some that are sold with the housing and some without. A mechanic gave me a quote that correlates price-wise with the full sensor + housing part. Is there any reason why I'd…
user453441
  • 275
  • 2
  • 3
  • 8
6
votes
1 answer

Why do modern PCMs prefer MAP over MAF

Why do modern PCMs prefer to use pressure sensors to estimate the air charge going into an engine instead of air flow meters. Eg they typically use a MAP sensor and complex software to estimate air charge based on current cam positions when a simple…
rollsch
  • 193
  • 1
  • 8
6
votes
1 answer

Is this a right MAF signal?

I've just bought this MAF sensor for the injection setup I'm going to build, and first I was struggling to figure out how to connect it. It's used for several BMW cars.(E38,E39,Z3) On the connector it says "3 2 1" and the letters Sn and Ag. No idea…
Bart
  • 2,964
  • 1
  • 13
  • 28
6
votes
1 answer

1998 V6 Mustang -20+ LTFT on both banks

I just finished doing a bunch of work on my Mustang (replaced all gaskets down to head gaskets on engine, had the heads milled and a valve job done, replaced all the fuel injectors, new fuel injector, new plugs, wires, coil pack, new radiator, and…
OPcorki
  • 63
  • 4
5
votes
1 answer

How to clean the MAF sensor on a 1997 Nissan Altima?

I have a 1997 Nissan Altima sedan. I’ve been told the issues I’m having with my car is from the mass air flow sensor. I was wondering how to clean/repair this sensor and contact points the best? What would be the best way to do this besides replace…
user377
  • 91
  • 1
  • 2
5
votes
3 answers

Engine shudders when tachometer falls to idle RPM from around 2K RPM

We're talking about a 2005 Volvo S80 2.5T 5-cyl engine vehicle here. Back in late September was the first time I experienced this engine shudder/stutter behavior when the tachometer dial went from say something around 2k RPM and dropped to round…
jxramos
  • 1,880
  • 10
  • 34
  • 49
4
votes
1 answer

Chevy 2007 Trailblazer Sputtering in the Morning. Code P0171 has come up in the past

For a little over a month, the P0171 (System too Lean) code has been coming up. My brother has cleaned the throttle and the MAF (Mass Air Flow) sensor. It then worked fine for a few weeks, then the code came up again and the sputtering started. …
T.A
  • 41
  • 2
4
votes
1 answer

Calculating AFR using injector flow rate and mass air flow

Is injector flow rate = Mass fuel flow? If so then AFR = MAF/Injector flow rate. Can someone please confirm this?
Soumya Sen
  • 1,521
  • 3
  • 24
  • 47
1
2 3 4 5