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10
votes
1answer
71 views

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 ...
9
votes
2answers
3k views

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 ...
7
votes
1answer
52 views

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. ...
7
votes
3answers
743 views

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 ...
7
votes
2answers
9k views

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 ...
6
votes
4answers
83k views

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 ...
6
votes
1answer
37 views

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 ...
5
votes
3answers
17k views

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 ...
5
votes
1answer
3k views

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 ...
4
votes
1answer
141 views

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?
4
votes
1answer
168 views

Can I use the same AFR sensor on both banks (bank 1 sensor 1 and bank 2 sensor 1)

Have 1mzfe (skip this paragraph if you don't want backstory) codes p1135/p1130/whatever the ones for the other bank are/ all showed up at the same, perfect time. ie when I was broke. Since then car ...
3
votes
1answer
24 views

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 ...
3
votes
1answer
202 views

How can one calculate volumetric efficiency without a MAF sensor?

I am completely new in the field of OBD2 sensor; I am looking for a method (or a formula) to calculate Volumetric Efficiency of: Diesel Car Petrol Car which do not have a MAF sensor. Can anyone ...
2
votes
2answers
52 views

1996 Ford E350 (5.8L) Mass Air Flow Sensor - where is it?

I can't find the MAF sensor on my 96 Ford E350. (Been googling for hours :)) In case a picture helps: Like I said, I've been looking for quite a while, and I can't find anything. Thanks!
2
votes
4answers
119 views

Check engine lights came up after Air filter change?

Yesterday I changed air filters in my car (Nissan supper saloon N16 - model year 2000). After installation the check engine light came on when I started the engine and the engine seemed to be running ...
2
votes
1answer
2k views

What exactly is OBD Calculated Load?

OBD Calculated Load is defined as: LOAD_PCT = [current airflow] / [(peak airflow at WOT@STP as a function of rpm) * (BARO/29.92) * SQRT(298/(AAT+273))] But when I am in neutral and I open the ...
2
votes
1answer
45 views

What does the OBD error code P0100 mean?

What does the OBD error code P0100 mean? I have an engine misfire with the check engine light on in my Nissan N16 Supper Saloon -1300cc - 2000 model year. The engine started to produce less power. An ...
1
vote
1answer
458 views

MAF sensor output signal vs. RPM?

I read that the MAF sensor output voltage increases as RPM increases. The ECU uses this voltage to determine other things, like idle RPM, ignition timing, fuel injectors, etc. Where can I find the ...
1
vote
2answers
1k views

Where is the MAF Sensor on a Peugeot 207?

I'm getting loss of power when idling and spluttering and the OBD is telling me the engine is running rich. I want to try cleaning or replacing the MAF sensor, but... I'm no mechanic and I'm just not ...
0
votes
2answers
4k views

Why does RPM jump between 1000 and 2000 at standstill (2002 Mercedes-Benz CLK 200 K)?

My car has a kind of a rough idle and it's like it gives a bit of gas, meter goes between 1000 and 2000 rpm at standstill. Same if I shift up to 1 or 2nd gear. If I then take it for a drive, car jerks ...