Low Boost Issue Involves MAF sensor

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Yesterday | 01:33 PM

Eliasd

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3rd Gear

Joined: May 2026

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Low Boost Issue Involves MAF sensor

I have a 2004 early model 6.0 PowerStroke with the 2003 engine in it. It has the Icp by the turbo. I am having an issue where I will only make 10 lbs of boost unless I unplug my MAF sensor. My Map sensor is reading correctly. I can't remember what my EPB sensor reads; however, it is new, and the line has been cleaned out.
When I unplug my MAF sensor, it seems to go to default values and makes 25 lbs of boost. The truck has a new turbo and all-new boots.
My question is, does unplugging the MAF sensor default the ECU strategy not to monitor any values? If so, what tests can I do to see what is going on and why it is that when I unplug the MAF sensor, the truck runs as it should?
Also, the MAF sensor is brand new, and it has the same readings as the previous sensor.

Yesterday | 02:46 PM

bismic

Fleet Owner

Joined: Nov 2003

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Do you have the "Inferred EBP" flash?

Do you have a PID labeled "EBPInf" or EBP-Inf"?

Where did you get the new MAF sensor?

Last edited by bismic; Today at 04:37 AM.

Yesterday | 03:42 PM

Eliasd

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3rd Gear

Joined: May 2026

Posts: 3

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Quote:

Originally Posted by bismic

Do you have the "Inferred EBP" flash?

Do you have a OID labeled "EBPInf" or EBP-Inf"?

yes I do here are my values at idle. And I was wrong my boost with it plugged in shows 17 psi full throttle.

Last edited by Eliasd; Yesterday at 03:48 PM.

Yesterday | 03:58 PM

bismic

Fleet Owner

Joined: Nov 2003

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With the "Inferred EBP flash" (used only in the '03 engines), the PCM relies on the MAF and MAP.

Make sure you thoroughly inspect your MAP sensor hose for leaks and tears and loose fit.

Yesterday | 04:41 PM

Eliasd

Thread Starter

3rd Gear

Joined: May 2026

Posts: 3

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Quote:

Originally Posted by bismic

With the "Inferred EBP flash" (used only in the '03 engines), the PCM relies on the MAF and MAP.

Make sure you thoroughly inspect your MAP sensor hose for leaks and tears and loose fit.

thanks it has a brand new hose on it. The clamps are tight but old so maybe… I will try putting on a new clamp to see if it’s leaking out the side under load.

Yesterday | 08:14 PM

LEEDSnDeed

Mountain Pass

Joined: Dec 2025

Posts: 104

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It has to relearn when they are inferred... Clear all codes.. Let it idle. There is a pid for "ok to learn VGT" and a pid for "VGT inferred learned" . It will idle up and down for a little while. If there are no issues with the map, mass air, or VGT then it will learn and give you boost again.... Ah, the good old days, back when International was trying all kind of stuff to 'fix' things on the 6.0l