FYI: Fresh Air Temp Sensor
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Junior User
Joined: Feb 2003
Posts: 96
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FYI: Fresh Air Temp Sensor
I am new to the board, and I'll be asking for help momentarily, however, I thought I would share something if it hasn't been covered already.
My wife's 2000 Expedition (I expect other years are similar) began running rough at an idle, and it seemed to lack power. No warning lights (fault codes) were set, but she knows when something isn't right with the beast.
I have a good scan tool, so I ran all the tests. I ran through the sensors after it warmed up, and here is what I found...
The intake air temp sensor was showing a constant 64 degrees, and at the time, the air temp was 20 degrees lower.
Therefore, even though the sensor was kaput, the computer didn't flag it because the reading was within a "normal" temp range, and (I assume) it set the mix too lean. Replacing the sensor (~$15) cured the problem.
I hope that this helps someone out there who might be scratching their head over a similar problem, and for any Ford software engineer who might be listening, perhaps you might want to put this temp value in persistent memory and compare it in a running list of... oh, say... 20-30 starts? If the value never deviates, then I think it's safe for the ECU to report that there is a problem.
My wife's 2000 Expedition (I expect other years are similar) began running rough at an idle, and it seemed to lack power. No warning lights (fault codes) were set, but she knows when something isn't right with the beast.
I have a good scan tool, so I ran all the tests. I ran through the sensors after it warmed up, and here is what I found...
The intake air temp sensor was showing a constant 64 degrees, and at the time, the air temp was 20 degrees lower.
Therefore, even though the sensor was kaput, the computer didn't flag it because the reading was within a "normal" temp range, and (I assume) it set the mix too lean. Replacing the sensor (~$15) cured the problem.
I hope that this helps someone out there who might be scratching their head over a similar problem, and for any Ford software engineer who might be listening, perhaps you might want to put this temp value in persistent memory and compare it in a running list of... oh, say... 20-30 starts? If the value never deviates, then I think it's safe for the ECU to report that there is a problem.
Thread Starter
|
Junior User
Joined: Feb 2003
Posts: 96
Likes: 2
FYI: Fresh Air Temp Sensor
Hi Bob.
I didn't drive it normally being a.... um... Chevy Man, but my wife was indeed complaining about it all the time.
So, to answer your question... I don't know for sure. As soon as she reported it to me, I was out there running diagnostics and pulling my hair out until I solved it.
We expect that the computerized systems will be able to report all the problems, but when things like this appear, they fall into the "twilight zone."
And, in all fairness to Ford, I recall a problem I had with a Pontiac with TB injection... GM chose to have the charcoal canister purge valve vacumn-driven instead of solenoid-driven to save money. A pinhole in the diaphram drove the ECU nuts as it tried to compensate for the ever-changing mixture due to the vapors being drawn through the diaphram and into the base of the throttle body.
Of course, both manufacturers have indeed come a long way... and that concept mustang is starting to look nicer than a vette!
AJ
I didn't drive it normally being a.... um... Chevy Man, but my wife was indeed complaining about it all the time.
So, to answer your question... I don't know for sure. As soon as she reported it to me, I was out there running diagnostics and pulling my hair out until I solved it.
We expect that the computerized systems will be able to report all the problems, but when things like this appear, they fall into the "twilight zone."
And, in all fairness to Ford, I recall a problem I had with a Pontiac with TB injection... GM chose to have the charcoal canister purge valve vacumn-driven instead of solenoid-driven to save money. A pinhole in the diaphram drove the ECU nuts as it tried to compensate for the ever-changing mixture due to the vapors being drawn through the diaphram and into the base of the throttle body.
Of course, both manufacturers have indeed come a long way... and that concept mustang is starting to look nicer than a vette!
AJ
