Moving the Mass Air Flow Sensor

Long Term Report

It's been about 6 months since I moved the MAF right next to the throttle body housing and my gas mileage has been down about 4-5 mpg overall. I thought that it was because it was due to the cold weather (winter and spring) but it's because of the new MAF position. The engine has been incredibly loud resulting in comments like "is your engine going to blow up?" from my wife and daughter.

I figure that there is too much turbulence from the cylinders when the MAF is close to the throttle body. The MAF/ECU can't get a good read on what is happening because of the turbulence. The main purpose of the intake muffler is to smooth out the cylinder turbulence so the MAF can do its job. I re-installed the hollow intake muffler and gas mileage and performance are back to the previous settings and it doesn't sound like I have a broken exhaust system any more.

The extra snap in throttle response is not worth the noise and the loss in gas mileage for the little better throttle response.

The following has been left here for historical purposes:

Normally, the MAF is located next to the air filter with an intake muffler or pipe between it and the throttle body housing. For a better throttle response, move the MAF next to the throttle body housing. This will put the order of objects: air filter, intake muffler, MAF then throttle body housing. This eliminates the air mass from the intake muffler and let the MAF respond faster to throttle changes. This mod puts a little snap in to the throttle response.

Here's the MAF moved closer to the throttle body with teardrop shaped intake muffler.

Barrel shape intake muffler

On Ranger pickups, I've seen two styles of intake mufflers: tear drop shape and barrel shape. My truck has the tear drop shape. If you use one of the rubber hoses from a barrel shaped intake muffler, you can mount the MAF directly to the throttle body. Then use the remaining rubber hoses to connect the intake muffler (which I shortened) to fit the air filter on.

Here's a picture where I've moved the air filter directly next to the MAF

I've removed the tube between the cone style air filter and MAF. Now the throttle body connects directly to the MAF and the MAF connects directly to the air filter. Sorry for the picture, it was -20 degF when this picture was taken and I had routed the fresh air through some aluminum ducting to the exhaust manifold to help warm up the engine faster. At the tip of the cone filter, I had drilled out a hole and mounted the Intake Air Temperature sensor in it. You can see the wires going into the aluminum ducting.

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Copyright February 2011 Eugene Blanchard