Help!!! Code 56 Cant Find The Problem!!

[84/89 coupes]

Ok so I am new to this site so I will go over whats been going on.

89 lx coupe - 306, stock block, crank, rods, forged pistons, trickflow track heat top end w/ stg 2 cam, 75mm bbk throttle body, egr delete, bbk fender mount CAI, Pro-M 75 maf (calibrated for cai, 24# inj).... nothing crazy.

Problem: this is a fresh motor and setup. Car ran perfectly fine before with the stock 5.0 in it. I recently have been having a hell of a time trying to diagnose code 56. High maf voltage.
Previous to going for a tune I had a bbk maf on the car and it would throw code 66, and the car you buck and jerk violently while trying to drive.... so I swapped out the maf with an known working pro m from a friend. Seemed to get rid of code 66 but didnt try to drive it until tune. Went for a tune with a new Pro M bullet MAF and everything seemed to go fine.
Got the car home from the tuner (8 hours away) and tried to drive it. Car started to buck and jerk violently again and had no power and was popping out the intake tube. Pulled codes and now get code 56. Since then I have ran continuity test on some wires and seemed to find that at the 60 pin connector to Maf And Mafrtn wires were not working or hooked up.... ran 2 new wires and still no change. Have tested to the best of my knowledge voltages etc while car was running and at the maf they seemed to be within range, fyi I am not a wiring genius at all, honestly hate wiring.

So it worked fine on the dyno and now its a PAIN IN THE ASS and is causing nothing but a headache.

I have been told its probably a faulty wire, pegged maf, etc etc etc but I just cant seem to track this down. Has battery relocated to trunk with all new body/engine/battery grounds........ I am just stumped and am ready to ditch the efi and throw a carb on it or ditch the whole car and concentrate back on my race car.
This was supposed to be a basic setup/ daily driver to enjoy that lots have assembled similar to my setup.

Anyone have an idea??

 

[jrichker]

Code 56 MAF - output voltage too high. Failed MAF sensor, short between MAF sensor and heater or short in wiring between pin A (12 volts) and pins C or D.

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 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

Disconnect the MAF sensor, battery negative post and computer connector. The computer connector is located under the passenger side kick panel & is secured by a single 10 MM bolt. Do not make any resistance checks without disconnecting the connectors. You will get incorrect readings.

Check the resistance between the MAF signal wiring and power. Pin D on the MAF (dark blue/orange wire) and Pin A (red wire) should be 1 megohm or higher (meter shows infinite resistance or open circuit.). Pin C on the MAF (tan/light blue wire) and Pin A (red wire) should be 1 megohm or higher (meter shows infinite resistance or open circuit.).

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

 

[84/89 coupes]

I was debating running 4 new wires to the maf but after looking at the pinout I cant cut pin 37 or I will lose power to everything else but when I run a continuity test from "A" on the maf and pin 57 I get nothing...... I tested the ohm between "D" and "A" and got 116.6k
Between "C" and "A" I got 3.76k

Not sure what that even means

 

[84/89 coupes]

Everytime I go to look at the pinout I get confused. Because based on the diagram if I probed pin 57 and the "A" on the maf I should get some sort of reading, no?

 

[84/89 coupes]

Help??????

 

[jrichker]

Everytime I go to look at the pinout I get confused. Because based on the diagram if I probed pin 57 and the "A" on the maf I should get some sort of reading, no?

Pin 57 (A on the MAF connector) is power from the computer circuit. It only shows power when the ignition is in the Run or Start position. First test reading, use the body or engine for a ground, then use pin 40 (B on the MAF connector) for a ground.

 

[84/89 coupes]

Just so I dont mess up. I should be able to cut pin 57 and run a wire to the MAF? And same for pin 40 for a ground? I want to run 4 new wires.

Also what does it mean if I tested the ohm between "D" and "A" and got 116.6k
Between "C" and "A" I got 3.76k

 

[Detroiit]

I had a similar problem. Long story short is my car was in a accident and come to find out after lots of headaches it was several wires that connect to the kick panel ecu were severed and not even hooked up. Not sure if this helps but its something

 

[84/89 coupes]

Yeah I am leaning towards some bad wire somewhere....

 

[jrichker]

Just so I dont mess up. I should be able to cut pin 57 and run a wire to the MAF? And same for pin 40 for a ground? I want to run 4 new wires.

Also what does it mean if I tested the ohm between "D" and "A" and got 116.6k
Between "C" and "A" I got 3.76k

Was the wiring harness disconnected from the computer and MAF when you did the test of the wiring? Or were you testing the only the MAF's resistance?

 

[84/89 coupes]

Battery: disconnected
Harness from computer: disconnected
Maf harness disconnected from maf housing

 

[jrichker]

Battery: disconnected
Harness from computer: disconnected
Maf harness disconnected from maf housing

With both ends of the harness disconnected the resistance between any two wires should be infinite, an open circuit. Just be sure not to touch the probe tips when making resistance measurements, since your results will be incorrect.

 

[Anewjer00]

So what was the issue here ? FIXXED ?