I will tell you two magnificent stories that are directly related both to this sensor and to such a concept as: “The influence of the character of a Russian person on the performance of components and assemblies of a Japanese-made car”.
(. amazingly said by its initial incomprehensibility. )
I have nothing against Forums and Conferences on the Internet.
But I want to say that if you listen to the advice, you must do this selectively and carefully.
But the best thing, as Life itself shows, is to “listen to the advice of Professionals”.
We have talked about this many times..
And we’ll still say, still remind, because there is a constant “bumping into a rake”.
Came to arid (see note) a man on a NISSAN car, the problem is: “Does not go”.
Indeed: we press the gas, and the engine does not develop revs.
The malfunction history is ordinary: the client was “sentenced” by the previous MAF sensor and advised instead, put another, but. three-pin (the old one was 5-pin).
As you know, now many have the words on their lips and in their minds: “NO AUTO CAR SERVICE”!
And man I decided to do everything myself, all the more – “business something”!
It’s not difficult:
1. Listen to tips
2. Remove the “old” “flow meter” and put “new” (“and reconnect the wires a little.”)
3. Ride further.
The man did everything “wisely,” he made all connections with preliminary checking of the circuits with a multimeter, but his car.
That’s right – “did not go”.
There is nothing to do here, the question of “distrust” in car services was immediately forgotten.
Went to a car service.
They lifted the hood, looked, and this is the picture that opened:
Okay – “snot”,
okay – “may close”,-
“DOES NOT WORK!”, That’s the most important thing.
The scanner showed a voltage of more than 2 volts.
However, if there are “right hands” and “sharpened brains”, then the malfunction can be “cured”.
We look at photo 1: if contacts 2 and 3 (“read” from left to right) are interchanged, then what will happen?
That’s right, the engine will work fine.
All the fuss for troubleshooting and troubleshooting took 10 minutes, no more.
Everything is simple?
Everything is “so simple”.
But this is “external simplicity”, behind which Knowledge + Experience.
To do this, and go to a car service – “for brains”.
What can be concluded?
Can I say: “Trust the professionals” – ?
It’s good that it ended so easily.
But judging by the “appearance” of the contacts (how the electrical tape was wound), judging by the fact that the issue of “shorty” between the contacts was resolved at the “high school” level. things could end up much worse.
so what? Do it yourself or go to the professionals?
You can change MAF 5-pin to 3-pin.
But do not abuse such alterations, do not experiment “just like that”.
There is no inlet air temperature sensor on the 3-pin “flow meter”.
It seems to be a “trifle”?
It seems that if you do not take into account the fact that the incoming air temperature sensor is directly involved in calculating the “mass flow of passing air” – it is he who informs the ECU about the air temperature, which is directly related to the air density.
Without such a correction, a mistake is possible that subsequently affects the fuel correction.
Okay, let’s leave this car and look at another, the same Nissan, “European”, 2002 model year with 3.0 liter engine.
This story is worthy of entry in the “tablet”.
Although the case is quite ordinary.
The client was also “sentenced” by the MAF sensor and he immediately bought a new one, set it and continued to rejoice and “untwist” the engine up to 6.000.
The car “flew”.
But not for long.
After a while, she again “got up”.
During this time, the Client managed to find himself in Moscow and, having heard about the high level of technical services, went to a specialized store and purchased a “branded” MAF sensor there .
The car again “flew”, but again not for long.
And the client was a person with claims and ambitions.
He arrived at the store and promised to “sue” everyone if he was not given a “normal” sensor.
Gave him a sensor.
Just to get rid.
What was next?
The story repeated, I will not bore the description of the same effect called “does not go”.
There are already in the store thinking.
They could count money and do a little analysis.
And sent the client!
. in car service.
Arid is a calm person, but he restrained himself, because the Client and he began to suspect him of something and make some complaints.
Sorted out long enough.
But figured out.
Below is a test circuit for this sensor. (BOSCH HFM5)
1 – intake air temperature sensor
2 – supply voltage +12 volts
3 – Mass
4 – 5 volt reference
5 – “DATE” – measured signal
(Airflow direction (arrow on the sensor):
left to right, from pin 1 to pin 5)
– securely close the inlet and outlet channels of the sensor
– apply voltage to the sensor
– measured voltage: 0.98 – 1.02 volts
– open the inlet and outlet channels of the sensor
– direct a stream of air to the “input” of the sensor
– measured voltage (increases with the intensity of the air flow): max = 4.5 volts
If the values of the measured voltages do not correspond to the above data, it can be assumed that the sensor is defective (dirty).
You can really check the pollution issue in this way:
Gently pry and remove the sensor cover:
Visually or using an optical instrument, determine the degree of contamination:
photo 2 – “good”, the sensor is clean, workable
photo 3 – “faulty”, the sensor is dirty, inoperative
You can read more information about this sensor in an article by Khabarovsk Diagnost Vladimir Bekrenyov at: link
“I’m not so rich that I would buy cheap things!”
Yes, it is in this expression that the whole trouble of our Client lies.
And not only him.
The whole cause of the malfunction, the cause of the failure of one “flowmeter” first, then the second, third – the reason was.
Who works in a car service, he will understand me and be sure to remember such cases.
Remember the appearance of such “left” air filters.
He will remember how much time was “killed” to determine the malfunction, but, most importantly, to try to prove to the Client about the need to replace the air filter and then purchase only “branded” products!
First, look at photo 4:
The red arrows indicate the “garbage” that may remain on the protective grille of the MAF-sensor .
These are “large fractions”.
And imagine how much “small” debris literally flies through the sensor!
It will fly through that HOLE, which is called the “air filter” of the left “manufacture”.
Diagnostic from the Sakhalin Island Mark Nikolaevich Fialkovsky shared a very valuable remark on the diagnosis and verification of the MAF sensor (see note):
“. According to my statistics, 99% of the MAF sensor failure occurs after an unprofessional replacement of the air filter.
When replacing, none of these 99 percent removed the sensor before replacing it, as I do now and give advice to all Clients. And no one cleared the entire airway to the damper.
And the following happens.
When the engine is running on the old filter, dust particles still penetrate through the filter and through leaks between the housing and the filter. And part of them settles inside the air channel to the damper on the walls.
When removing, we bend, as a rule, the air duct and some dust particles are released.
When removing the air filter from its seat, a lot of dust flies out from leaks between the filter and the housing.
And here the main thing: If everything is left like this, then a certain percentage of this “shnyaga” will fall on the sensor, and the rest – in the engine.
And do not forget about crankcase ventilation, which also contributes to the “killing” of the MAF.
It is written: “A man came to Arid, the problem is this:” Does not go “.
Arid – a person who deals with issues of diagnosis and repair
cars. For a long time and successfully resolves issues on the “variators”.
You can’t definitely say that “he likes to deal with the Nissan, but
cars of this brand are “registered” in front of the gates of his workshop.
In our Forum ( http://forum.autodata.ru ) his nickname is SKYLINE77.
Fialkovsky Mark Nikolaevich.
Diagnostic, lives and works on Sakhalin Island.
He is a Man and a Professional in his business, is my First
A teacher in the diagnosis and repair of Japanese cars.
I owe him a lot.
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