Mechanics

FUEL INJECTION PROBLEMS RANOUT OF GAS

Mazda Protege

I have a 1991 Mazda protégé (fuel injected) which was a perfectly running car until I let myself run out of gas. On my way to the pumps it hesitated stalled jumped and the rest. Once the fuel was in. It drove perfectly for 1.5 days and then shut down whenever I stopped or came to a stop or turned a corner. I changed the distributor cap and cleaned the plugs. The car acted like it wanted to start but did not (“CATCH”). I took it to a mechanic who informed me that the computer was sending a signal of “too much gas to the engine” or some such nonsense. I just received this bill and estimate. What do you think? And what the heck is a mass air flow thingamajig and what does it have to do with my fuel injection


ALREADY BILLED
Timing belt change notice $
Tow $ 50.00
: CHECK NO START – $140.00
REINSTALLED PARTS
& REPLACED IGNITION
ROTOR - R& I SPARK
PLUGS, CLEANED AND
ADJUSTED – TEST FUEL
PRESSURE & IGNITION
SPARK – CHECKED
MASS AIR FLOW METER


ESTIMATE
D222 ignition rotor $ 9.60
Waste disp $ 4.50
7420029 mass flow sensor $294.90
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MsSnooty2SHus
June 4, 2007.



A mass airflow sensor is used to determine the mass of air entering an electronically fuel-injected engine. The air mass information is necessary for the engine control unit to calculate and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the vehicle's operating environment, and this is an ideal application for a mass sensor.
There are two common types of mass airflow sensors in usage on gasoline engines. They are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.

Both approaches are used almost exclusively on EFI (electronic fuel injection) engines. Both sensor designs output a 0 - 5.0 volt signal that is proportional to the air mass flow rate, and both sensors have an IAT sensor (intake air temperature) incorporated into their housings.

When a MAF is used in conjunction with an exhaust gas oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the engine's ECU, and the EGO sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.

Tiny
DanCarlson
Jun 5, 2007.