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Old 10-27-2013, 12:06 AM   #41
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Hey everyone. This may seem like a stupid question, but is there any particular way of removing the engine cover? I tried simply pulling on it and feel like I'm going to break it.
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Old 10-27-2013, 12:18 AM   #42
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Originally Posted by ROM3000 View Post
Hey everyone. This may seem like a stupid question, but is there any particular way of removing the engine cover? I tried simply pulling on it and feel like I'm going to break it.
Just pull up on it, the studs resist you from pulling initially, but release their grip on the engine cover with enough force, without damaging the cover.
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Old 10-27-2013, 12:30 AM   #43
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Originally Posted by suss6052 View Post
Just pull up on it, the studs resist you from pulling initially, but release their grip on the engine cover with enough force, without damaging the cover.
Thanks. I'll give it a try again.
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Old 10-27-2013, 12:39 AM   #44
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Originally Posted by lovemyfucus View Post
The ST is speed density tuned and runs off of 3 MAP sensors unlike many cars that base their calculations off of the MAF.
What you said does not apply to the 2013 Focus ST so which ST are you talking about?

(I'm assuming that you're not just being a parrot that repeats misinformation)
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Old 10-27-2013, 12:59 AM   #45
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Quote:
Originally Posted by Kabigon View Post
What you said does not apply to the 2013 Focus ST so which ST are you talking about?

(I'm assuming that you're not just being a parrot that repeats misinformation)
Are you sure about that?

The 2013 Focus ST has three MAP sensors, one on the inlet of the charge air cooler which is denoted in the service manual as a MAPT (Manifold Absolute Pressure and Temperature) sensor, one in the intake manifold as a regular MAP sensor, and the third is incorrectly referred to as the MAF when it is in fact actually another Bosch MAP sensor.



Denoted as #3, 5 and 8 on the engine electronic controls component location for the left side of the engine block (front of car).

Ergo it is not incorrect to refer to the car as being a MAP based or speed density car vs the base MK3 which uses a mass air system to meter the incoming air into the engine. Where on earth did you get the idea that the ST is a MAF car?

https://accessecu.com/support/docs/t...scriptions.pdf

Even the tuning houses recognize this as being a MAP based car, not a MAF based one for purposes of tuning and calibrating it based on the tables being those used by a speed density car not a mass air one.
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Old 10-27-2013, 03:13 PM   #46
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Originally Posted by suss6052 View Post
Are you sure about that?
I'm going by the service manual and the IDS.



Quote:
Originally Posted by suss6052 View Post
Where on earth did you get the idea that the ST is a MAF car?
You are confusing me again as I made no such claim.

In any case, It's not uncommon for an engine to employ a MAF and MAP sensor.
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Old 10-27-2013, 03:58 PM   #47
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Quote:
Originally Posted by Kabigon View Post
I'm going by the service manual and the IDS.

You are confusing me again as I made no such claim.

In any case, It's not uncommon for an engine to employ a MAF and MAP sensor.
It would appear that the service manual incorrectly describes a MAP sensor as a MAF due to it's proximity to the air filter. This may have been copied and pasted from the base Focus section of the manual. The base number of the two exposed sensors (on the intake manifold, and at the filter) matches that of a MAP sensor and not a MAF.



Part number: CV2A-9F479-AA is seemingly incorrectly referred to as the mass air flow sensor.




Part Number AG91-9F479-AB

Yes the prefix and revision are different as it's not precisely the same sensor however in Ford's part naming convention parts with the same base number are generally the same type of part.

This is further evidenced by searching fordparts.com for this base number (9F479) and the only results that show up for the 2013 Ford Focus are all referred to as MAP sensors with all but one for the 2.0 L EcoBoost engine. No where in their parts descriptions does it call this a MAF sensor except for in the service manual.

Base number - 12B579 is used by ford for MAF sensors typically, and this is the case on the base Focus as well which is an air flow based air metering vehicle, vs the pressure based metering of the ST.

Essentially the base focus uses 1 MAF sensor to determine the mass flow rate of the air going into the engine, where as the ST uses three MAP sensors to determine the density and pressure of the air to figure out the velocity. This makes the MAP car less susceptible to modifications having a positive effect on performance without calibration changes where as with the base car within the limits of it's programming the MAF will compensate for increases in air flow more directly.

If I'm wrong I would like to know why they call what on the surface is a MAP sensor and call it an air flow sensor when it does not use the hot wire resistance technique of the regular MAF sensors.
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Old 10-28-2013, 02:26 PM   #48
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Suss - think about it...

What possible use would a MAP sensor have on the outlet of the air box (i.e. what exactly is being "measured")?

I could understand if it was used (only) as a intake air temperature sensor.
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Old 10-28-2013, 02:53 PM   #49
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Quote:
Originally Posted by Kabigon View Post
Suss - think about it...

What possible use would a MAP sensor have on the outlet of the air box (i.e. what exactly is being "measured")?

I could understand if it was used (only) as a intake air temperature sensor.
Directly it can only ever measure temperature and or pressure, the PCM would need to calculate from these values the incoming air flow assuming a standard density value stored in the tables.

It may act like a mass air sensor, but only after the computer has calculated the information from known information. It does not directly measure the flow rate of the air.

Quote:
Ideal Gas Law : PV= nRT (Pressure times Volume equals moles of gas times ideal gas constant times temperature)

Basically they are different methods of arriving at the same general conclusion, however the way they get there is different.

It would be important to know the temperature, pressure, and density of the incoming air in order to compensate for changes in environmental conditions.

It's pretty much just getting into semantics at this point, but the ST uses a MAP sensor to estimate the mass air flow rate from the temperature and pressure at three locations.
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Old 11-02-2013, 12:54 AM   #50
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Quote:
Originally Posted by suss6052 View Post
Directly it can only ever measure temperature and or pressure, the PCM would need to calculate from these values the incoming air flow assuming a standard density value stored in the tables.

It may act like a mass air sensor, but only after the computer has calculated the information from known information. It does not directly measure the flow rate of the air.




Basically they are different methods of arriving at the same general conclusion, however the way they get there is different.

It would be important to know the temperature, pressure, and density of the incoming air in order to compensate for changes in environmental conditions.

It's pretty much just getting into semantics at this point, but the ST uses a MAP sensor to estimate the mass air flow rate from the temperature and pressure at three locations.


Measure pressure (vacuum) before the throttle body (or turbo) has no meaning. Atmospheric pressure is measured directly by the PCM.

According to the OBD System Operation Summary, the sensor after the airbox is simply a temperature sensor. I believe that this kind of "standalone" temperature sensor does not exist so in that case a MAP or MAF sensor is used (both have temperature sensors in addition to their primary function).

A second sensor is mounted to the intercooler outlet to monitor boost air pressure and temperature and a third sensor (the "real" MAP sensor) is mounted to the intake manifold for the speed density function.

https://www.motorcraftservice.com/vd.../OBDSM1300.pdf
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