Bad MAFS?

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NoStickers
Posts: 840
Joined: Tue Jun 17, 2003 5:00 pm
Car: 1991 240sx w/ sr (RIP)
1989 240sx w/ ka
1996 240sx donor car (coming soon)
Location: Ft. Bragg

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Ok this is the third time I've posted this due to the hacking, etc. but bear with me b/c I never got a chance to read any posts.

I can't shift past 2500 and have heard that is a symptom of a bad MAFS. I think it may be bad but not totally sure if my wiring has been shorted. Can anyone check the resistances on their MAFS and compare it to mine? :help

The pins in the MAFS are labeled A (empty spot), B, C, and D.

B - C 10.15 Mega Ohms

B - D 10.14 Mega Ohms

C - D 4.01 Kilo Ohms

A - No Connection

What else can I test? Thanks for any help I can get.


User avatar
NoStickers
Posts: 840
Joined: Tue Jun 17, 2003 5:00 pm
Car: 1991 240sx w/ sr (RIP)
1989 240sx w/ ka
1996 240sx donor car (coming soon)
Location: Ft. Bragg

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:help

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SpeedRacer1
Posts: 3144
Joined: Fri Jul 26, 2002 7:44 pm
Car: 1990 240SX, G35

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First thing to check when you have a bad MAFS issue is to locate your ground wire. Make sure the MAFS is properly grounded.

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NoStickers
Posts: 840
Joined: Tue Jun 17, 2003 5:00 pm
Car: 1991 240sx w/ sr (RIP)
1989 240sx w/ ka
1996 240sx donor car (coming soon)
Location: Ft. Bragg

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All three wires go to the ecu and the ecu should be grounded. We did a continuity check and there were no shorts from the ecu to MAFS.

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NoStickers
Posts: 840
Joined: Tue Jun 17, 2003 5:00 pm
Car: 1991 240sx w/ sr (RIP)
1989 240sx w/ ka
1996 240sx donor car (coming soon)
Location: Ft. Bragg

Post

Ok I bought a SOHC MAFS and the plugs are different. Has everyone who uses the SOHC MAFS had to rewire the plugs?

robbbby
Posts: 585
Joined: Thu Sep 26, 2002 12:41 pm

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Here is a little test you can do to test the MAF but it requires you cutting the harness off your car.

Take your MAF sensor off you car along with the harness and strip the three wires

You need a battery charger that has a 2A charge to do this. Plug your battery charger in and connect the positive to the +12V wire of the MAF connector harness. Connect the ground to the ground wire on the harness. Take a electrical tester, put the ground lead to your ground which is connected to the charger and the positive to the third wire of your MAF which isn't hooked up to anything, this is your MAF signal. You should get a reading of around 0.4V, now blow through the MAF, you should see the voltage go up, if it is working right it will go up more in voltage the harder you blow through. The MAF reads from 0-5 volts. If you blow through and get like 1.5-2V your MAF is most likely in good working condition.

User avatar
NoStickers
Posts: 840
Joined: Tue Jun 17, 2003 5:00 pm
Car: 1991 240sx w/ sr (RIP)
1989 240sx w/ ka
1996 240sx donor car (coming soon)
Location: Ft. Bragg

Post

Ya I might try that... didn't want to cut my harness up though...


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