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air charged temp sensor

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Old Mar 26, 2004 | 07:39 AM
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Question air charged temp sensor

I have an 87 302 that is real sluggish on take-off and sort of pops also someone told me to check the air charged temp sensor along with a few other things what is this and how do I check it? thanks
 
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Old Mar 26, 2004 | 09:11 AM
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You can measure the resistance of the sensor to check it. A Haynes manual will have the resistance values - I can't remember them right off hand. The ACT is in the intake manifold between the fuel injectors for cylinders 5 and 6.
 
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Old Mar 29, 2004 | 05:26 AM
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Cool

Would this sensor be in the same place on a '94 F150 5.0 engine? is it actually threaded into the intake manafold itself?
 
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Old Mar 29, 2004 | 06:41 AM
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Possibly - I think Ford moved it to the airbox around that time, but I don't know for sure. It's in one of the two places.
 
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Old Mar 29, 2004 | 04:27 PM
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Please forgive my ignorance, but what exactly is the air box? I have looked on the intake manifold between the number 5 and 6 cylinder injectors, and it doesn't seem to be there.
I have bought a new sensor and it looks like the coolant temp sensor execpt it has an air gap kind of tip to it, I guess thats why they call it an air charged temp sensor.
 
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Old Mar 29, 2004 | 04:27 PM
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I don't think they moved it from the intake manifold because it is a resistor that changes value with engine temp. If it was in the air box it wouldn't be affected by engine temp. With the key forward you want about 5 volts at the connector. To check the sensor you want to check it cold first then warm the motor up to NOT and check it again. When it's cold the ACT sensor should have a high resistance. When the motor is hot it should have a low resistance.
 
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Old Mar 29, 2004 | 06:31 PM
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If your engine is mass air, then the air temp sensor was moved to the air filter box, it's on one side of it, just can't remember exactly where. Buy the way, it doesn't measure engine temperature, it measures incoming air temperature.
 
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Old Mar 29, 2004 | 06:47 PM
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Yes, the air filter housing is what I meant by airbox. It is actually better for the sensor to be mounted there because it isn't affected by engine temperature like it is in the intake manifold. It's an air temp sensor, so it should have a resistance that corresponds to the ambient air temperature when you test it.
 
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Old Mar 29, 2004 | 08:54 PM
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The Haynes manual tells you exactly what I said that the resistance will(should) change from a cold engine to a warmed up one. I'm sure it's because of the SD vs MAF. With MAF you're actually measuring the mass of the air flowing into the motor so it makes sense that you would want the act sensor close to the MAF sensor. SD is more of a calculation/estimate as to how much air is flowing. I assume that since the MAP sensor is measuring Manifold Pressure the computer needs to know the temp of the air in the manifold for an accurate calculation. Make sense to me but I don't for for sure. If anybody has a better explanation (or the right one if I'm wrong) I welcome it.
 
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Old Mar 29, 2004 | 11:05 PM
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Originally Posted by RLKBOB
I assume that since the MAP sensor is measuring Manifold Pressure the computer needs to know the temp of the air in the manifold for an accurate calculation
Maybe, but the air is under a vacuum, so air temp is not as critical of a measurement as manifold vacuum. 89-93 mustangs are mass air, and had the ACT in the intake manifold, same place as the trucks. The ACT should always read what the ambient temperature is - that's what it's for, and that's why Ford chose to move it to the air filter housing, away from engine heat, to get a truer air temperature reading.
 
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Old Mar 30, 2004 | 06:49 PM
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Guys, I found my sensor actually yesterday, it is in the air box in the side closest to the firewall, I've got a new one ordered and will report IF this happens to fix my hard start trouble as of late. Thanks!
 
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