Oxygen sensor (smoking sensor)
1. It's a cold-start issue. So that ruled out a lambda/oxygen sensor issue as a cold engine running on choke bypasses the Lambda/oxygen sensor.
2. Can't be Intake leaks as the problem disappears when the engine warms up.
3. On cold starts immediate high throttle (>4k rpm) often prevented the issue from occurring. But its not good for the engine at all.
Thus, i figured it could be an air flow issue but not a leak. It could also be temperature related. Somehow the ECU was getting wrong info about either the air flow or the air temp and either over compensating or not compensating for the actual conditions. And AFAIK the 1.6 Duratech has a MAP instead of MAF sensor, it seemed a likely enough culprit here.
What's a MAP sensor?
The MAP or Manifold Absolute Pressure Sensor measures the absolute pressure in the intake manifold and compares it with a reference vacuum to enable the air mass to be precisely defined.
It then sends the appropriate voltage signal to the vehicle’s computer which decides whether to increase or decrease fuel supply to the engine and adjust spark advancement accordingly. Issues with MAP sensor can lead to various problems from excessive fuel consumption, miss fires, erratic idle, reduced engine performance, etc. A malfunctioning MAP sensor will almost always also result in the Engine Check warning light to come on. And before I start appearing like some amazing engineering whiz, i'd like to confess here that a lot of this is info gathered from various sources on the indispensable world wide web
Thus, I set about locating the MAP on the Fusion engine and to my horror discovered that it was almost inaccessible, buried deep beneath the Air Cleaner Outlet Pipe! The Air Pipe would have to be removed to access the sensor - not an easy job, especially the 'putting the pipe back on' part, as the Ford clamps that tighten the pipe ends are the clip types and not the screwed on ones. It was time for professional help and so, armed with all this info, a good Electrical Contact Cleaner spray, and a by now obsessive zeal I headed to my local mechanic.
The subsequent process of removal, cleaning and the results i am describing below:
The engine bay
Location of the MAP sensor and Throttle body
2. Can't be Intake leaks as the problem disappears when the engine warms up.
3. On cold starts immediate high throttle (>4k rpm) often prevented the issue from occurring. But its not good for the engine at all.
Thus, i figured it could be an air flow issue but not a leak. It could also be temperature related. Somehow the ECU was getting wrong info about either the air flow or the air temp and either over compensating or not compensating for the actual conditions. And AFAIK the 1.6 Duratech has a MAP instead of MAF sensor, it seemed a likely enough culprit here.
What's a MAP sensor?
The MAP or Manifold Absolute Pressure Sensor measures the absolute pressure in the intake manifold and compares it with a reference vacuum to enable the air mass to be precisely defined.
It then sends the appropriate voltage signal to the vehicle’s computer which decides whether to increase or decrease fuel supply to the engine and adjust spark advancement accordingly. Issues with MAP sensor can lead to various problems from excessive fuel consumption, miss fires, erratic idle, reduced engine performance, etc. A malfunctioning MAP sensor will almost always also result in the Engine Check warning light to come on. And before I start appearing like some amazing engineering whiz, i'd like to confess here that a lot of this is info gathered from various sources on the indispensable world wide web
Thus, I set about locating the MAP on the Fusion engine and to my horror discovered that it was almost inaccessible, buried deep beneath the Air Cleaner Outlet Pipe! The Air Pipe would have to be removed to access the sensor - not an easy job, especially the 'putting the pipe back on' part, as the Ford clamps that tighten the pipe ends are the clip types and not the screwed on ones. It was time for professional help and so, armed with all this info, a good Electrical Contact Cleaner spray, and a by now obsessive zeal I headed to my local mechanic.
The subsequent process of removal, cleaning and the results i am describing below:
The engine bay
Location of the MAP sensor and Throttle body
Close up of the Throttle Body and MAP sensor location, with air outlet pipe removed and the MAP also removed. Sorry the pic of the MAP sensor while it was in position didn't get saved.
Also notice the dirty throttle body. I spray cleaned it as well.
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