Mechanics

MASS AIR FLOW SENSOR

1997 Ford Ranger • 4.0L V6 RWD Automatic • 149,000 miles

I have 97 Ford Ranger 4.0L. Less than a year ago I replaced the mass air flow sensor. About a month ago it started humming like the old one. Is it possible that I just got a defective one or is there something causing the mass air flow sensor to fail? Other then the humming the truck is running fine and the check engine light has not come on. My air conditioning quit this year because it has a leak some place. Would that have any effect on the mass air flow sensor?

Thank You
Todd Miller
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Worthin52
August 5, 2014.




What do you mean by humming? Does it sound like a honk or buzzing sound? Has the check engine light come on? If it is more like a honking sound especially when coming to down to idle it is usually the idle air control valve that makes this sound. If it is different then get a scanner and monitor your fuel trims. If they long term is around +20% then check your pcv hose for a leak. They usually collapse and the air been sucked in is making that humming noise. Also monitor your mass air flow sensor at idle. Your grams per second should be around 4 grams per second.

JIS001
Aug 5, 2014.
I should have used the word buzzing its not a honking noise. It only happens at idle in gear and in park. I have also replaced the idle air control valve in the past year. The pcv and hose have also been replaced in the last year. The check engine light is not on and I have used my scan tool and dont get any error codes. I have had this truck for just over 2 year and have replaced almost everything related to emissions system.

Thanks Todd
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Tiny
Worthin52
Aug 5, 2014.
Sorry I am getting back late. I had an issue once where the camshaft position sensor synchronizer was making that same noise you are describing. Get a stethoscope or a long screwdriver and listen to see if the sound is coming from the Camshaft Position (CMP) sensor synchronizer. If it is replace the synchronizer assembly. Good luck and keep us posted please.

JIS001
Aug 7, 2014.
The problem was the idle control valve. What I m not sure of is why it failed. I replaced it less than a year ago. Was the one I purchased defective or did something else make it fail?

Tiny
Worthin52
Aug 7, 2014.

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