DIY MAF/IAT Sensor Service

[Pubtym]

"Background: Mass Airflow/Intake Air Temperature Sensor

Operation:
Mass Air Flow (MAF) sensor measures the weight and rate of air moving through a passage of a known volume or size. MAF sensors utilize hot wire or thick film technology. Signals generated may be analog or digital depending on the manufacturer. As more air passes through the MAF sensor the voltage or frequency increases proportionally. The EMS uses this information to calculate injector pulse-width and spark advance. Performance issues from MAF sensor failures range from no-start conditions to stalling, hesitation, stumble and improper air/fuel mixtures.

The Intake Air Temperature (IAT) sensor is a variable temperature sensitive resistor. Sensor resistance will change based on air temperature. The higher the temperature, the lower the resistance. The Engine Management System (EMS) provides a reference voltage and monitors the voltage drop between a fixed value internal resistance and the sensor resistance. This is called a voltage divider circuit.

IAT sensor values are used by the EMS to assist with the calculation of idle speed, fuel mixture and spark advance.

Related Symptoms:

A faulty MAF sensor due to loose connections, bad grounds, high resistance in the circuit, or opens in the circuit can cause the following symptoms:

A no start condition
Stalls at idle
Surging idle
Extended crank time when engine is cold
Hesitation
Stumble
Chuggle
Poor fuel economy"

With this background, I collected related step by step process for me to again safely inspect and clean as necessary the MAF/IAT Sensor assembly on the 2006 Itasca 8.1L Vortec. I currently intend to inspect and service it.. as a minimum..every 20,000 miles or air filter change which ever comes first.

Caution:Use care when handling the mass air flow/intake air temperature (MAF/IAT) sensor. Do not dent, puncture, or otherwise damage the honey-cell located at the end of the MAF/IAT. Do not touch the honey-cell and sensing elements or allow anything including non MAF designed cleaning solvents and lubricants to come in contact with them. Use a small amount of a non-silicone based lubricant, on the air duct only, to aid in installation.

Caution: Read and understand the Cautions and First Aid labels on the MAF cleaner prior to use.

Caution: Use eye protection at all times...especially when spraying the cleaner on the MAF/IAT sensor internal surfaces. Blow back of the cleaner into the eye area is possible with serious consequences.

1. Remove the rear half of the air cleaner box outlet duct.
2. Pull out the gray connector position assurance (CPA) retainer.
3. Push down on the black clip in order to disconnect the MAF/IAT sensor electrical connector.
4. Disconnect the MAF/IAT assembly with the rear half of the air filter box by loosening the Screw-Clamp holding the MAF/IAT Sensor to the air duct leading to the engine.
5. Remove the MAF/IAT and rear half of the air filter box for shop service.
6. Carefully, spritz the MAF/IAT internal sensor wires and honeycell surfaces with the cleaner. Allow cleaner to completely drain and evaporate (20-30 Min).
7. Wipe clean the external MAF/IAT and the internal surfaces of the air filter box and air duct leading from the MAF/IAT to the engine.
8. Reassemble/reinstall all and insure all screw-clamps are tightened securely.

Photos of the MAF/IAT at my various stages of disassembly and cleaning are posted IRV2 Photo gallery under photos for Pubtym on "MAF".
http://www.irv2.com/photopost/showga...00&ppuser=1483

[Pubtym]

"Background: Mass Airflow/Intake Air Temperature Sensor

Operation:
Mass Air Flow (MAF) sensor measures the weight and rate of air moving through a passage of a known volume or size. MAF sensors utilize hot wire or thick film technology. Signals generated may be analog or digital depending on the manufacturer. As more air passes through the MAF sensor the voltage or frequency increases proportionally. The EMS uses this information to calculate injector pulse-width and spark advance. Performance issues from MAF sensor failures range from no-start conditions to stalling, hesitation, stumble and improper air/fuel mixtures.

The Intake Air Temperature (IAT) sensor is a variable temperature sensitive resistor. Sensor resistance will change based on air temperature. The higher the temperature, the lower the resistance. The Engine Management System (EMS) provides a reference voltage and monitors the voltage drop between a fixed value internal resistance and the sensor resistance. This is called a voltage divider circuit.

IAT sensor values are used by the EMS to assist with the calculation of idle speed, fuel mixture and spark advance.

Related Symptoms:

A faulty MAF sensor due to loose connections, bad grounds, high resistance in the circuit, or opens in the circuit can cause the following symptoms:

A no start condition
Stalls at idle
Surging idle
Extended crank time when engine is cold
Hesitation
Stumble
Chuggle
Poor fuel economy"

With this background, I collected related step by step process for me to again safely inspect and clean as necessary the MAF/IAT Sensor assembly on the 2006 Itasca 8.1L Vortec. I currently intend to inspect and service it.. as a minimum..every 20,000 miles or air filter change which ever comes first.

Caution:Use care when handling the mass air flow/intake air temperature (MAF/IAT) sensor. Do not dent, puncture, or otherwise damage the honey-cell located at the end of the MAF/IAT. Do not touch the honey-cell and sensing elements or allow anything including non MAF designed cleaning solvents and lubricants to come in contact with them. Use a small amount of a non-silicone based lubricant, on the air duct only, to aid in installation.

Caution: Read and understand the Cautions and First Aid labels on the MAF cleaner prior to use.

Caution: Use eye protection at all times...especially when spraying the cleaner on the MAF/IAT sensor internal surfaces. Blow back of the cleaner into the eye area is possible with serious consequences.

1. Remove the rear half of the air cleaner box outlet duct.
2. Pull out the gray connector position assurance (CPA) retainer.
3. Push down on the black clip in order to disconnect the MAF/IAT sensor electrical connector.
4. Disconnect the MAF/IAT assembly with the rear half of the air filter box by loosening the Screw-Clamp holding the MAF/IAT Sensor to the air duct leading to the engine.
5. Remove the MAF/IAT and rear half of the air filter box for shop service.
6. Carefully, spritz the MAF/IAT internal sensor wires and honeycell surfaces with the cleaner. Allow cleaner to completely drain and evaporate (20-30 Min).
7. Wipe clean the external MAF/IAT and the internal surfaces of the air filter box and air duct leading from the MAF/IAT to the engine.
8. Reassemble/reinstall all and insure all screw-clamps are tightened securely.

Photos of the MAF/IAT at my various stages of disassembly and cleaning are posted IRV2 Photo gallery under photos for Pubtym on "MAF".
http://www.irv2.com/photopost/showga...00&ppuser=1483

[DonavonP]

Nice presentation Pubtym!! Pictures too. Thank you! Is this work on your Winnebago? I assume so, the air tubes look familiar.

Let me know how it feels to blow by that parked Corvette.

[Pubtym]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DonavonP:
Nice presentation Pubtym!! Pictures too. Thank you! Is this work on your Winnebago? I assume so, the air tubes look familiar.

Let me know how it feels to blow by that parked Corvette. </div></BLOCKQUOTE>

Thanks for positive feedback....and recognition of effort made to assist others in same.

It is my 2006 Itasca 35U...21,000 miles.

[FrontRangeRVer]

Ah....never mind....

Good post Pubtym. Thanks!

[Gregg]

Excellent post,
Thank You.

[Pubtym]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by FrontRangeRVer:
Ah....never mind....

Good post Pubtym. Thanks! </div></BLOCKQUOTE>

Thank you.

[rickandcheryl]

Good post. Old Corvette (same MAF) performance trick is to remove the screen and do a little very careful triming on the wire support. Ran my 2000 Vett for 15K miles like this with no problems. Rick

[Joe Gilbert]

Nice report but I'm somewhat confused (not unusual). If my memory, from a year ago, when I last cleaned my MAF, is correct my MAF doesn't look like this. I thought my MAF only had two wires and those were 90' apart. Also I could remove the screen to better clean the MAF.

Is this a MAF from an 8.1L Workhorse? Perhaps newer models are different than mine or perhaps my memory really is bad.

Again, nice work.

Joe

[Pubtym]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Joe Gilbert:
Nice report but I'm somewhat confused (not unusual). If my memory, from a year ago, when I last cleaned my MAF, is correct my MAF doesn't look like this. I thought my MAF only had two wires and those were 90' apart. Also I could remove the screen to better clean the MAF.

Is this a MAF from an 8.1L Workhorse? Perhaps newer models are different than mine or perhaps my memory really is bad.

Again, nice work.

Joe </div></BLOCKQUOTE>

Thanks Joe,
It is the OE MAF from my 2006 Itasca. Could be a
different series MAF from your 2004.

[Pubtym]

Update: I have completed MAF/IAT cleaning on all three of my vehicles..one (2006 Itasca) is process posted here. The other two vehicles all had OE MAF/IATs. 99 Ford F-150 5.4L Auto, 107,000miles. 98 Geo Tracker, Manual, 117,000 miles. Summary: All demonstrated enhanced drive ability/performance...especially in the lower rpm applications (1000-2000) where even slightly fouled MAF/IAT can produce too rich fuel mixture. On auto tranny vehicles...initial accel (first 1 inch throttle application) engine accel was consistent/smooth with shift points velvet.

Simply put...in my opinion, MAF/IAT cleaning can-does work @ routine service intervals eventhough most manufacturers do not currently list it as a routine service.

About $7/can for three vehicles. Best $7 I ever spent on routine auto service.

You be the judge...