Idle Problem help??

[asecretfile]

87GT mass air converted, At first I had to unplug my mass air meter for the car to idle right or it would die so I though maybe dirty mass air meter so I cleaned with CRC mass air cleaner and then I got curious so I unplugged my IAC and plugged back in my mass air meter. With it this way with the IAC UNplugged, I can either plug in or unplug the mass air meter with no change to idle taking place. Revving somewhat skipping at low rpm but ok at higher rev with a very slow transition back to idle from revving. Almost like idle will only hold with one or the other unplugged

any ideas??

thanks

 

[jrichker]

See the "Surging Idle Checklist for help with all your idle/stall problems. The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes] for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[asecretfile]

Update...

Cleaned the IAC valve...when I have both the IAC and mass air sensor connected, if I pull the mass air sensor out of the housing the car will idle perfectly, but it stalls out when I insert the sensor back into the housing. I know the sensor works because I can lightly blow on it while its out of the housing and it will rev the engine

any ideas?

thanks

 

[jrichker]

What codes are you getting?

 

[asecretfile]

What codes are you getting?

It didnt give any codes, with both key on engine off and key on engine on...thats what was weird

trying to figure out what in the housing that would stall the engine, that open air wouldnt...and even me blowing on it didnt stall it, just caused it to breifly rev

thanks

 

[jrichker]

You should have gotten an 11, two single flashes in a row. That says the computer's inner workings are Ok and the wiring to put it into self test is good.

 

[asecretfile]

You should have gotten an 11, two single flashes in a row. That says the computer's inner workings are Ok and the wiring to put it into self test is good.

yea I got the 11 I just meant no trouble ones

strange that the car runs/idles fine with everything plugged up including MAF long as I take it out of the sampling tube. Maybe I have a blockage in the housing havent checked that yet

 

[1/4mile_runner]

Loosen up both sides, so you can turn/twist the MAF. Twist it both ways till the idle smooths out. It worked for me when I had a 75mm bullet.

 

[asecretfile]

Loosen up both sides, so you can turn/twist the MAF. Twist it both ways till the idle smooths out. It worked for me when I had a 75mm bullet.

Well, the problem I had was no idle at all with it in, it would just die altogether. I'll try seeing if by turning the MAF it will allow me to reinsert the sensor

thanks for the reply

 

[asecretfile]

What codes are you getting?

I got codes 85 (which Ive deleted my emission stuff)
and code 66 which I saw that means low mass air flow signal which Im not sure how to remedy

BTW I was filling with oil before my idle issue and a little dripped onto the MAF meter plugin harness which I wiped off and didnt think anything about...could it be maybe related? If so I have like 2 other ones I got from the junkyard

thanks

 

[jrichker]

Clear the codes by removing the jumper once they start to dump, or by pressing the button on your scanner. Run the car with the MAF connected and all the parts installed so you could drive the car. Dump the codes again: if you get code 66 again, you either have bad wiring or a bad MAF sensor.

Be sure to read the test path below for more help.

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).

Changes in RPM causes the airflow to increase or decease, changing the voltage output.. 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. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

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 wiring connector and ground. Make your measurement with the MAF disconnected from the wiring harness.


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

 

[asecretfile]

Clear the codes by removing the jumper once they start to dump, or by pressing the button on your scanner. Run the car with the MAF connected and all the parts installed so you could drive the car. Dump the codes again: if you get code 66 again, you either have bad wiring or a bad MAF sensor.

Be sure to read the test path below for more help.

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).

Changes in RPM causes the airflow to increase or decease, changing the voltage output.. 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. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

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 wiring connector and ground. Make your measurement with the MAF disconnected from the wiring harness.


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

10-4

I was reading low voltage on the meter with my digital meter and again this morning codes 85 and 66

could it be even though I blow across it and it revs the engine that it could still be defective?

thanks

 

[asecretfile]

I had 3 mass air meters here all 3 of which were bad. I got one at the junkyard out of a V8 Thunderbird for 7.00 and runs great now. Im surprised it still works. I got caught in pouring rain when I was pulling it out and had nothing to put it in except under my shirt lol

thanks for all the help :SNSign:

 

[jrichker]

The Mass Air meters are computer specific and will not always provide an output that matches the needs of your engine. The only one that will interchange without problems is 94-95 Mustang GT MAF - $40-$100. It is 70 MM instead of the stock 55 MM on regular stangs built prior to 94. It uses a slip on duct on the side that goes to the throttle body and a 4 bolt flange on the other. You need a flange adapter to fit the stock slip on air ducting that goes to the air box. Wiring plugs right in with no changes.

Metal flange adapter http://www.kustomz.com/cat3.html Buy the TR70 for $44.95. Or spend some time on eBay looking for one that may fit.
Try AutoZone and ask for 81413 - Spectre / 3 in. Aluminum Intake Mass Air Flow Sensor Adapter at $12.00. You may have to order it online.

The 94-95 Mustang 5.0 MAF & sensor is also found on:
1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A,
Evidently the –A1A, -A2A, AA, etc. on the end of the part number is a minor variant that did not change the operating specs. You should be able to ignore it and have everything work good.