Cleaning an Air Flow Meter on a 85 RX-7 GSL-SE?
06-30-10, 04:38 AM
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Cleaning an Air Flow Meter on a 85 RX-7 GSL-SE?
1985 RX-7 GSL-SE
I've had some idling and stalling problems, which (after testing & ruling out a bunch of ignition / fuel pump stuff) might be the AFM. There is a flapper door that regulates something somehow, and I think that it may be dragging on some crud.
Does anyone know about cleaning the AFM? Use Mass Air Flow Sensor Cleaner?
Does the flapper hinge pins need lubrication?
What is that little black plastic uvula that hangs down on the air filter side of the flapper? Is that a "don't touch that" kind of thing, like the two wires in a MAF sensor?
Does anyone know how the AFM actually works, and why the flapper doesn't oscillate, but apparently will go to the right degree of opening for the engine speed?
Is there a method of testing the AFM that I (who knows little about electronics) can do?
From Discount Auto Parts website:
Purpose: The Mass Air Flow sensor is used to measure (actually weight) the amount of air entering the engine. This measurement is used by the engine computer or ECM to calculate proper amount of fuel injected into the cylinders in order to provide optimum combustion and low emissions.
Maintenance Tips/Suggestions: MAZDA RX7 Mass air flow sensor requires no regular maintenance. On mass air flow sensors with a sense wire, this wire can become contaminated with dust particles. These particles can be removed with automotive solvents that are safe for the use on mass air flow sensors.
MAZDA RX7 mass air flow sensors are commonly misdiagnosed. Before replacing the mass air flow sensor check for air leaks in the connecting air ducts and intake manifold. These leaks can cause similar symptoms as a malfunctioning mass air flow sensor.
Failure symptoms: Problems with Mass Air Flow sensors are common. Bad or contaminated MAZDA RX7 Mass Air Flow sensor can possibly cause a wide range of various vehicle drivability problems such as stalling, especially when the engine is cold, misfiring, poor acceleration, etc. In addition, a problem with the Mass Air Flow sensor often causes the "check engine" or "service engine soon" light in the vehicle instrument panel to illuminate.
I've had some idling and stalling problems, which (after testing & ruling out a bunch of ignition / fuel pump stuff) might be the AFM. There is a flapper door that regulates something somehow, and I think that it may be dragging on some crud.
Does anyone know about cleaning the AFM? Use Mass Air Flow Sensor Cleaner?
Does the flapper hinge pins need lubrication?
What is that little black plastic uvula that hangs down on the air filter side of the flapper? Is that a "don't touch that" kind of thing, like the two wires in a MAF sensor?
Does anyone know how the AFM actually works, and why the flapper doesn't oscillate, but apparently will go to the right degree of opening for the engine speed?
Is there a method of testing the AFM that I (who knows little about electronics) can do?
From Discount Auto Parts website:
Purpose: The Mass Air Flow sensor is used to measure (actually weight) the amount of air entering the engine. This measurement is used by the engine computer or ECM to calculate proper amount of fuel injected into the cylinders in order to provide optimum combustion and low emissions.
Maintenance Tips/Suggestions: MAZDA RX7 Mass air flow sensor requires no regular maintenance. On mass air flow sensors with a sense wire, this wire can become contaminated with dust particles. These particles can be removed with automotive solvents that are safe for the use on mass air flow sensors.
MAZDA RX7 mass air flow sensors are commonly misdiagnosed. Before replacing the mass air flow sensor check for air leaks in the connecting air ducts and intake manifold. These leaks can cause similar symptoms as a malfunctioning mass air flow sensor.
Failure symptoms: Problems with Mass Air Flow sensors are common. Bad or contaminated MAZDA RX7 Mass Air Flow sensor can possibly cause a wide range of various vehicle drivability problems such as stalling, especially when the engine is cold, misfiring, poor acceleration, etc. In addition, a problem with the Mass Air Flow sensor often causes the "check engine" or "service engine soon" light in the vehicle instrument panel to illuminate.
06-30-10, 04:27 PM
#2
Interesting that Discount Auto Parts has such a thorough write up on our MAFs. As far as solvent cleaners, use brake cleaner. The FSM has further electrical tests you can perform. In order of priority, check for leaks post AFM, check the electrical connections in the plug, clean the MAF.
06-30-10, 05:23 PM
#3
Factory service manual can be downloaded here
http://wright-here.net/cars/rx7/85_manual.html
or here
http://foxed.ca/rx7manual/85_manual.html
I've attached page 4B-44 with the MAF info. In my experience, if the door moves smoothly its OK. The door is sucked open by the air drawn into the engine. More air goes in, more the door opens. The door is attached to a variable resistor so the resistance changes as the door opens and closes. The fuel pump switch comes on as soon as the door opens. Be sure to check the connection between the two large hoses (looks like one) that go from the throttle body to the MAF. The splice, halfway up, is clamped together with a metal clamp. Air leaks at this splice can cause problems.
http://wright-here.net/cars/rx7/85_manual.html
or here
http://foxed.ca/rx7manual/85_manual.html
I've attached page 4B-44 with the MAF info. In my experience, if the door moves smoothly its OK. The door is sucked open by the air drawn into the engine. More air goes in, more the door opens. The door is attached to a variable resistor so the resistance changes as the door opens and closes. The fuel pump switch comes on as soon as the door opens. Be sure to check the connection between the two large hoses (looks like one) that go from the throttle body to the MAF. The splice, halfway up, is clamped together with a metal clamp. Air leaks at this splice can cause problems.
07-01-10, 04:10 PM
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If that "crud" you speak of is like what I had, it is the rubber from your air filter. I do not know why, but the underhood temperature causes the rubber to melt and get sucked in. Mine was clear to the throttle body. As stated above, brake cleaner works great on cleaning it all up.
