again, How to cure code 66 (maf below minimum voltage) ????

HAITHAM · 11-08-2001, 03:51 AM

????

------------------
94 COBRA # 926/5009
TFS track heat heads (ported), Cobra intake (ported), 24# Injectors, 3/8" Phenolic spacer, E303 Cam, TFS 1.7 rr
BBK 1 5/8" headers, BBK 65mm TB, Pro-M 80mm MAS, PIH kit w/ A9L computer, FMS 3.55 ratio
BBK 190 lph fuel pump, Paxton fpr, MSD'S, March Pulley's, Pro-5 tower power shifter, Autometer shift light (5600),
Intellitronix Air/Fuel gauge, Eibach Sportline Springs, Tokico 5-way adjustable, Granatelli Motorsport Subframe

PKRWUD · 11-08-2001, 05:02 AM

You're going to have to break out your DMM and spend the day checking circuits. 99% of the time, a code 66 is caused by one of the following:

Open MAF circuit,
Open VPWR circuit to MAF sensor,
Open PWR GND circuit to MAF sensor,
MAF circuit shorted to ground,
Faulty ECA or MAF sensor,
Air leak before or after MAF sensor,
MAF sensor disconnected.

Those are the things you have to check.

Take care,
-Chris

------------------
Retired Moderator
MustangNet

My site: Peckerwoods Pit Stop

My teams site: Jim Porter Racing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

HAITHAM · 11-08-2001, 06:33 AM

How to check the circuit ?

2FastLX · 11-08-2001, 06:41 AM

I got the same code when I first got my car back together, along with some EGR codes, and a couple others. I don't know if the O2's were what was causing the problem, but before I changed the O2 sensors I cleared the codes and it kept coming back. I replaced my O2 sensors and reset the computer and cleared the codes again and it never returned. That was the only thing I did to the car.

------------------
Gunning for 12's!

Buy your parts here
ICQ# 42269241

PKRWUD · 11-08-2001, 10:23 AM

The correct way to check them is with a break-out box, but since you probably don't have one, you will have to disconnect the harness at the ECM, and determine which wires are which, in relation to the MAF sensor wires, and check them for continuity, short to ground, or an open. You also must inspect the intake tubing before and after the MAF sensor, and make sure there is no air leaking in.

Take care,
-Chris

------------------
Retired Moderator
MustangNet

My site: Peckerwoods Pit Stop

My teams site: Jim Porter Racing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

HAITHAM · 11-12-2001, 07:27 AM

How to check MAF voltage, there are 4 pin. in the MAF harness ?

PKRWUD · 11-12-2001, 09:10 AM

MAF wires, and what they are, what to test and what you should find:

A: Red wire, VPWR. This wire supplies battery voltage to the MAF. There are two tests to perform. First, check the wire for continuity from the MAF harness connector to the ECM. Second, check for battery voltage between the Red wire and ground, with the harness disconnected from the MAF, and with the Key On and the Engine Off (KOEO).

B: Black wire, PWR GND. This wire is directly connected to the battery ground. There are also two tests here. For both tests, disconnect the harness from the MAF. With the key OFF, check for continuity between the Black wire and the negative battery post. For the second test, check for battery voltage between the Black wire and the positive battery post.

C: Tan wire with a Light Blue tracer, MAF RTN. This wire delivers a signal back to the MAF from the ECM. It is a ground signal, but it is controlled by the ECM. Do not confuse this wire with battery ground, as it will not always be able to complete a circuit with another positive battery source. Test this wire for continuity between the MAF harness connector and the ECM.

D: Dark Blue wire with an Orange tracer, MAF SIG. This is the wire that sends a signal from the MAF to the ECM. There are several tests for this wire. First, check this wire for continuity between the MAF harness conector and the ECM. Second, connect the DMM to this wire and to the Black wire, and check for infinite resistance. Third, connect the DMM to this wire and to the Tan wire with the Light Blue tracer, and check for infinite resistance. Finally, with everything connected and the engine running, use the positive DMM lead to back-probe this wire at the MAF harness connector , and touch the negative DMM lead to the negative battery post, and make sure that the DC voltage is between .2vdc and 1.5vdc.

Take care,
-Chris

11-08-2001, 03:51 AM	#1
HAITHAM Registered Member Join Date: Jun 2000 Location: Saudi Arabia Posts: 130	again, How to cure code 66 (maf below minimum voltage) ???? ???? ------------------ 94 COBRA # 926/5009 TFS track heat heads (ported), Cobra intake (ported), 24# Injectors, 3/8" Phenolic spacer, E303 Cam, TFS 1.7 rr BBK 1 5/8" headers, BBK 65mm TB, Pro-M 80mm MAS, PIH kit w/ A9L computer, FMS 3.55 ratio BBK 190 lph fuel pump, Paxton fpr, MSD'S, March Pulley's, Pro-5 tower power shifter, Autometer shift light (5600), Intellitronix Air/Fuel gauge, Eibach Sportline Springs, Tokico 5-way adjustable, Granatelli Motorsport Subframe

11-12-2001, 09:10 AM	#7
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	MAF wires, and what they are, what to test and what you should find: A: Red wire, VPWR. This wire supplies battery voltage to the MAF. There are two tests to perform. First, check the wire for continuity from the MAF harness connector to the ECM. Second, check for battery voltage between the Red wire and ground, with the harness disconnected from the MAF, and with the Key On and the Engine Off (KOEO). B: Black wire, PWR GND. This wire is directly connected to the battery ground. There are also two tests here. For both tests, disconnect the harness from the MAF. With the key OFF, check for continuity between the Black wire and the negative battery post. For the second test, check for battery voltage between the Black wire and the positive battery post. C: Tan wire with a Light Blue tracer, MAF RTN. This wire delivers a signal back to the MAF from the ECM. It is a ground signal, but it is controlled by the ECM. Do not confuse this wire with battery ground, as it will not always be able to complete a circuit with another positive battery source. Test this wire for continuity between the MAF harness connector and the ECM. D: Dark Blue wire with an Orange tracer, MAF SIG. This is the wire that sends a signal from the MAF to the ECM. There are several tests for this wire. First, check this wire for continuity between the MAF harness conector and the ECM. Second, connect the DMM to this wire and to the Black wire, and check for infinite resistance. Third, connect the DMM to this wire and to the Tan wire with the Light Blue tracer, and check for infinite resistance. Finally, with everything connected and the engine running, use the positive DMM lead to back-probe this wire at the MAF harness connector , and touch the negative DMM lead to the negative battery post, and make sure that the DC voltage is between .2vdc and 1.5vdc. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

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11-08-2001, 05:02 AM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	You're going to have to break out your DMM and spend the day checking circuits. 99% of the time, a code 66 is caused by one of the following: Open MAF circuit, Open VPWR circuit to MAF sensor, Open PWR GND circuit to MAF sensor, MAF circuit shorted to ground, Faulty ECA or MAF sensor, Air leak before or after MAF sensor, MAF sensor disconnected. Those are the things you have to check. Take care, -Chris ------------------ Retired Moderator MustangNet My site: Peckerwoods Pit Stop My teams site: Jim Porter Racing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.

11-08-2001, 06:33 AM	#3
HAITHAM Registered Member Join Date: Jun 2000 Location: Saudi Arabia Posts: 130	How to check the circuit ?

11-08-2001, 06:41 AM	#4
2FastLX The Photoshop Guru Join Date: Feb 2001 Location: Mecca, Indiana Posts: 1,419	I got the same code when I first got my car back together, along with some EGR codes, and a couple others. I don't know if the O2's were what was causing the problem, but before I changed the O2 sensors I cleared the codes and it kept coming back. I replaced my O2 sensors and reset the computer and cleared the codes again and it never returned. That was the only thing I did to the car. ------------------ Gunning for 12's! Buy your parts here ICQ# 42269241

11-08-2001, 10:23 AM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	The correct way to check them is with a break-out box, but since you probably don't have one, you will have to disconnect the harness at the ECM, and determine which wires are which, in relation to the MAF sensor wires, and check them for continuity, short to ground, or an open. You also must inspect the intake tubing before and after the MAF sensor, and make sure there is no air leaking in. Take care, -Chris ------------------ Retired Moderator MustangNet My site: Peckerwoods Pit Stop My teams site: Jim Porter Racing RACECAR spelled backwards is RACECAR HEY !!! Are you ASE Certified ??? If you are, ask me about iATN.