Nissan primera P12 F9Q intake temperature sensor |
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petterg
NPOC Guest Joined: 01 Jun 2014 Location: Norway Online Status: Points: 396 |
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Posted: 18 Aug 2017 at 9:17pm |
For the past 10 months I've been having a mystic performance issue with my 2004 P12. It starts to perform well after about 300km with injector cleaner on the tank, but after 300km without injector cleaner in fuel the problem returns. Also, on cold days (temp below 0C) the idle fluxes when engine i warm, but not when it's cold.
In the warm days this summer, the engine has randomly got more power, even without injector cleaner on the tank. When I say it gets increased power, it is shown in ODB2 live readings as increased values of turbo pressure, intake pressure, mass air flow and fuel rail pressure. However the performance does not feel as much better as the numbers indicates. Lately I realized there is something called "intake temperature" available through the ODB2 interface. I compared this data between my cars, and noticed that in the car performing well, the "intake temperature" is about the same as outside temperature, while in the car with low power the "intake temperature reads about 10-20C warmer than the outside temp. Coolant temperature has been a part of my standard live data monitoring since before the performance issue started. For normal driving the coolant temperature of the low performing engine is about 2C warmer that the well performing engine. Under heavy load the coolant temperature of the low performing engine is about 10C warmer than the well performing engine. This indicates that the engine temperature is not as much warmer as the intake temperature say. Where is the sensor for "intake temperature"? Is it a part of MAF? I've swapped MAF between the cars, but nothing changed. If the intake temperature sensor is part of the MAF, and the sensor is based on measuring circuit resistance, this probably indicates increased resistance in the cables going to the sensor? Will a faulty intake temperature reading cause the engine power to drop? Could the higher reading indicate some cooling issue with the engine even though the coolant temperature does not indicate it's that much warmer? (My other car, with well performing engine, is a 2005 P12 also with the F9Q engine, but it has a improved turbo.) |
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p11primeragt
NPOC Guest Joined: 29 Jul 2011 Online Status: Points: 18750 |
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The intake temp sensor if faulty could lead to loss of performance if it's reading hotter than normal.
I cant remember weather it's part of the maf or not on these. |
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petterg
NPOC Guest Joined: 01 Jun 2014 Location: Norway Online Status: Points: 396 |
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Thanks.
I bought a wireless outdoor thermometer and placed the sensor in front of the battery, just above the air filter inlet. This showed about 5C warmer in the low performing car. How can that be? The only differences I can tell is that the battery of the low perfoming car is AGM, 80Ah and is a bit larger in size (the well performing car has the cheapest 50Ah battery in store). Also the low performing car is missing the under engine isolated plastic cover. There is a sensor placed behind the radiator, near the top. Probably a temp sensor. Does anyone know what it's called? What could it called in ODB2 readings? Any suggestions how to move on with debugging? |
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p11primeragt
NPOC Guest Joined: 29 Jul 2011 Online Status: Points: 18750 |
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Get me a pic of the sensor you mean and it location and I'll might be able to tell you which one it is.
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petterg
NPOC Guest Joined: 01 Jun 2014 Location: Norway Online Status: Points: 396 |
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Here are two pictures of it. It's in the center of both pictures.
https://drive.google.com/file/d/0B2AaZQHY1mPaaG9HTTFsWVlZMTA/view?usp=sharing https://drive.google.com/file/d/0B2AaZQHY1mPaWG9SZUV1VjJ0TUE/view?usp=sharing |
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p11primeragt
NPOC Guest Joined: 29 Jul 2011 Online Status: Points: 18750 |
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I cant get the links to work.
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petterg
NPOC Guest Joined: 01 Jun 2014 Location: Norway Online Status: Points: 396 |
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p11primeragt
NPOC Guest Joined: 29 Jul 2011 Online Status: Points: 18750 |
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Is that not just the power supply for the fan/s?
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petterg
NPOC Guest Joined: 01 Jun 2014 Location: Norway Online Status: Points: 396 |
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No, the fan motor is further down. Inside the plastic is a thick steel wire/tube shaped like a coil.
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