MAF Voltage
Thread Starter
Instructor
Joined: Mar 2010
Posts: 101
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From: Kissimmee Florida
MAF Voltage
I can now get the Code 33 to do it when its cold. I did a voltage check, and have 12V .. Coming out of the data line with it unplugged from maf got 5V whith it plugged in 0v when it starts at idle (3.5v) goes up when giving it gas.
These values seem right ?
Also want to know what MAF i have. Cant find a name just M-T and a pat number on the case.
These values seem right ?
Also want to know what MAF i have. Cant find a name just M-T and a pat number on the case.
Last edited by dlee425; Jul 3, 2013 at 07:18 PM.
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Thread Starter
Instructor
Joined: Mar 2010
Posts: 101
Likes: 0
From: Kissimmee Florida
From what i can tell from the fsm is all reading are done with the maf unhooked, If this is the case all seems great.
I have Winaldl but do not know what normal ranges are for the maf and how to save the raw data..
Any idea ?
Thanks,
Donnie
One other question. Is the 86 know for any problems in the firewall connector. This code seems to be related to temp as it dont do it when it gets hot.
I have Winaldl but do not know what normal ranges are for the maf and how to save the raw data..
Any idea ?
Thanks,
Donnie
One other question. Is the 86 know for any problems in the firewall connector. This code seems to be related to temp as it dont do it when it gets hot.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The MAF power relay supplies 12 volts to power the MAF.
The output of the MAF goes to the ECM. There is a pullup resistor in the ECM that connects to 5 volts, so you will see 5 volts if the MAF connector is disconnected or there is a bad connection at the MAF (a bad connection or open wire is usually what causes an error code 33).
The MAF output signal is proportional to air flow. It will be very low at idle and close to 5 volts at high RPM.
Your measured values look good.
This is what the bottom of my MAF looks like. It is the original one that came in my car when I bought it in 1985:
The output of the MAF goes to the ECM. There is a pullup resistor in the ECM that connects to 5 volts, so you will see 5 volts if the MAF connector is disconnected or there is a bad connection at the MAF (a bad connection or open wire is usually what causes an error code 33).
The MAF output signal is proportional to air flow. It will be very low at idle and close to 5 volts at high RPM.
Your measured values look good.
This is what the bottom of my MAF looks like. It is the original one that came in my car when I bought it in 1985:
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Thread Starter
Instructor
Joined: Mar 2010
Posts: 101
Likes: 0
From: Kissimmee Florida
So its an after night problem. II have winaldl and even looks good there cold and hot, I have the newest prom 1228109 in it.
Its not making any sence to me. I trace intermitt problems all the day but this one is nuts.
Iam goinf to do a datalog with winaldl and see if anyone can see whats going on.
Thread Starter
Instructor
Joined: Mar 2010
Posts: 101
Likes: 0
From: Kissimmee Florida
[QUOTE=Cliff Harris;1584325657]The MAF power relay supplies 12 volts to power the MAF.
The output of the MAF goes to the ECM. There is a pullup resistor in the ECM that connects to 5 volts, so you will see 5 volts if the MAF connector is disconnected or there is a bad connection at the MAF (a bad connection or open wire is usually what causes an error code 33).
The MAF output signal is proportional to air flow. It will be very low at idle and close to 5 volts at high RPM.
Your measured values look good.
This is what the bottom of my MAF looks like. It is the original one that came in my car when I bought it in 1985:
Mine just says M-T and patent number on it has one screen in the front. No thin wire, looks like its built into the boatd and thas a TIP120 on a heat sink. Been working for the last year and winaldl shows cold and hot it is working..
The output of the MAF goes to the ECM. There is a pullup resistor in the ECM that connects to 5 volts, so you will see 5 volts if the MAF connector is disconnected or there is a bad connection at the MAF (a bad connection or open wire is usually what causes an error code 33).
The MAF output signal is proportional to air flow. It will be very low at idle and close to 5 volts at high RPM.
Your measured values look good.
This is what the bottom of my MAF looks like. It is the original one that came in my car when I bought it in 1985:
Mine just says M-T and patent number on it has one screen in the front. No thin wire, looks like its built into the boatd and thas a TIP120 on a heat sink. Been working for the last year and winaldl shows cold and hot it is working..
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