I went through the check list that jrichker provided.I cleaned and lubed all of the connectors.All of the volt meter checks came into specs.I checked pin 50 it also was working in the sensor reading ranges. I checked the grounds and battery voltage.Unhooked the bat. for an hour.When I started the car up the light came back on .I checked the koeo and got a 66 .This car is stock except for the Mac infender cold air an h-pipe no converters .It is a GT stock 302.with 120000 miles on it .It has new plugs and wires about 2 months ago.The maf is stock Ford.for 19 pd injectors.Thanks for any info.jrichker said:Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.
There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.
The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).
The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.
At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt
Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.
There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
Clocking the MAF is useful when you have a cold air kit or some other modification to the air box or air inlet before the MAF.
Clocking is turning the MAF housing so that the sensor element is in a different position. It changes the airflow through the MAF to place the sensor pickup in the place where the airflow is the least disturbed.
Thank you for your reply.the old meter numbers were e92 f12b579-aa also afh55-03 plus a stamp with 8k07.The new meter numbers are f1zf 12b579-aa also afh55-03b plus a stamp code sk07 I do see that when you crank the car up after the cel is reset that the light will be out for a few seconds then the rpms will drop some like a power interruption.Then the light jumps on.Is there a relay that controlls the computer that could momentarily cut the power to the computer?If this is possible what code would be stored?Probably farfetched on my part but I am looking for anything that could be causing this problem.Thank you for your help. Georgevristang said:There is no logical reason why the CAI would trigger the CEL.
Do you still have the old MAF?
Is the new MAF identical to the old one?
What is the part number on the MAS (the black electronics unit on the MAF assy) ???
The MAS number should be F1ZF, F1SF, or similar.
jason
BLKBELT said:Thank you for your reply.the old meter numbers were e92 f12b579-aa also afh55-03 plus a stamp with 8k07.The new meter numbers are f1zf 12b579-aa also afh55-03b plus a stamp code sk07 I do see that when you crank the car up after the cel is reset that the light will be out for a few seconds then the rpms will drop some like a power interruption.Then the light jumps on.Is there a relay that controlls the computer that could momentarily cut the power to the computer?If this is possible what code would be stored?Probably farfetched on my part but I am looking for anything that could be causing this problem.Thank you for your help. George
Yes I have tried another meter assy. off of another GT that I have.The new maf meter is a rebuilt unit from Advance.Both of these units do the same thing run fine ,turn on the cel .It has me stumped.My wife won't drive the car with the cel on.I can't say that I blame her.I have always told her to watch the gauges and warning lights and to stop if they weren't normal.She says that this cel light being on is not normal. lol Thanksvristang said:When you start the engine the computer is using a strategy called "Open Loop", when you hear the rpms drop and see the CEL come on, the computer is going into "Closed Loop"
What you are seeing is normal, and just a function of how the computer works.
I don't recognize the SK07 or 8K07 stampings you listed for the MAS part numbers, so I can't help there.
Have you tried hooking up the old MAS to the new tube?
Perhaps the new MAS is incorrect, or simply bad?
Where did you get the new MAF?
New or Used?
jason
Thank you Jason for your help.Are you saying that you have to have a specific maf sensor for each year model?The parts store lists the same maf unit for all 89-93 5os..You can't just buy the eletrical sensor.You have to get the housing with the sensor bolted on top as a CALIBRATED UNIT is what they read to me in there application guide.The book also included v6 a Tarus's for this same part number.I changed the old maf because the plug was not fitting well and would try to come unplugged .It had been unplugged inproperly too many times and banged around by the guy that owned this car before me.If the sensor has to be matched to something besides the mass air housing you are on the right track with my cel problem. Please let me know.Georgevristang said:Do you get the same code when you remove the CAI?
Using a MAF assy from another car doesn't quite rule out the possiblity of having the wrong meter.
It could be that both meters are wrong for that car.
Why did you replace the old meter? Can the old meter be installed?
jason
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?