Severe idle problem after MAF upgrade

[CManT1914]

I just switched out my stock MAF meter with a 73mm C&L one, and now the car will not idle. It cranks, bucks like a freakin bronco and then dies after a few moments. Is there some special way I need to line up the filament in the MAF with the O2 sensor in the intake tract? Ideas?

 

[shttygtstang]

did you unplug your batt. then let it learn it has a new maf .

i allways unplug my batt when changing somthing

did it do this before

 

[CManT1914]

Yea I unplugged the battery, and I've tried rotating the MAF different ways and the O2 sensor different ways and it aint doing nothing. What the heck is the matter with this?

 

[runningmole]

Are you sure it's calibrated for the correct injectors?

 

[5.0Droptop]

try cleaning the meter wires.

 

[jrichker]

Of all the people posting problems with an aftermarket MAF, almost all of them are C&L. I have not heard from many guys who bought a new Pro-M and had the type of problems that C&L MAF's have.

Now I will get down off my soapbox and offer some contructive help...

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

To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp

 

[CManT1914]

I dunno what the heck was the matter with it, but I'm giving it back to the guy I got it from tommorow. He has another one, an 80mm Pro-M calibrated for my 19 lb injectors, would it be worth it to pick it up instead? He's asking $125.

 

[5spd GT]

I dunno what the heck was the matter with it, but I'm giving it back to the guy I got it from tommorow. He has another one, an 80mm Pro-M calibrated for my 19 lb injectors, would it be worth it to pick it up instead? He's asking $125.

I'm assuming that isn't $125 more right? Just $125 straightup? How much for that C&L...

Ask the guy why he is getting rid of the C&L...did he have problems...what car did it previously come off of?

Good Luck

 

[CManT1914]

I'm assuming that isn't $125 more right? Just $125 straightup? How much for that C&L...

Ask the guy why he is getting rid of the C&L...did he have problems...what car did it previously come off of?

Good Luck

No the Pro-M is just $125 straight up. I talked to the guy this morning and he said that the C&L still had the 30 lb injectors sample tube in it. He said the Pro-M was the one calibrated for 19 lb injectors. I guess I should pay more attention next time. lol The C&L came off his last project car, I don't know what it was.

I put my stock MAF back in for now, I'm picking up the Pro-M in about 30 minutes.

 

[Michael Yount]

Unless you're gonna make other mods to your car, the meter is going to make little difference in peak performance. Your 94 car already has a stock 70mm maf in it. Why are you upgrading? The stock meter will flow plenty for your mods, and even some future mods.