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Discussion Starter · #1 ·
Hi all,

1999 EF V6 GLS A/T. I've never been able to find a separate MAP sensor, so have assumed it's combined with the IAT or MAF sensor. Then I stumbled across this...

GOSS MAP Sensor MP155 | Sparesbox (Australian/RHD)

I'm pretty sure the 4cyl has a separate MAP sensor because I see them for sale on many sites, and they look exactly the same as this one, but this is the only place I've seen that actually lists them as fitting the 2.5 V6. Can anyone confirm whether this vendor has it wrong, and if not, can you tell me where it is located on the engine? I can't see anything that looks like it in the obvious place (eg. anywhere between the MAF and the IAT....).

Thanks in advance :)
 

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Generally when an engine is fitted with a MAF sensor it won't have a MAP too. You only need to measure the air once, so it'll have one or the other.

If I helped you fix it, why not...

Your support is greatly appreciated
 

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Discussion Starter · #3 ·
Generally when an engine is fitted with a MAF sensor it won't have a MAP too. You only need to measure the air once, so it'll have one or the other.

If I helped you fix it, why not...

Your support is greatly appreciated
Thanks - yes that's kind of the conclusion I'd come to until I stumbled across this MAP sensor that supposedly fit my car (which already has a MAF sensor). I also recall reading some info from Hyundai Manual somewhere that indicated that the some of their cars have both, but it is incorporated into the air temp or MAF sensor. Not sure why they'd have both, but what would I know - I'm just an amateur learning as I go :)
 

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The 2.5L V6 has only the MAF sensor.
 

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Thanks - yes that's kind of the conclusion I'd come to until I stumbled across this MAP sensor that supposedly fit my car (which already has a MAF sensor). I also recall reading some info from Hyundai Manual somewhere that indicated that the some of their cars have both, but it is incorporated into the air temp or MAF sensor. Not sure why they'd have both, but what would I know - I'm just an amateur learning as I go :)
They use it for Atmospheric (Baro) pressure and not for load, MAF is for that. The Baro sensor is part if the MAF.
 

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The Baro sensor is part if the MAF.
WHAT!!
I imagine me not knowing that after all these years of diagnosing Hyundai engine management systems. Everyday is a school day...I guess :)

If I helped you fix it, why not...

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Discussion Starter · #7 · (Edited)
WHAT!!
I imagine me not knowing that after all these years of diagnosing Hyundai engine management systems. Everyday is a school day...I guess :)

If I helped you fix it, why not...

Your support is greatly appreciated
Yeah I read something along those lines from manual I mentioned earlier, but they didn't refer to it in the same way - just that in some models the MAP sensor is combined with either the MAF or Air Temp sensors... In short though, looking at my original question, it's looking highly likely that the seller in this case has erroneously referred to it as fitting my V6. Either way, I've already replaced both the air temp & MAF sensors anyway, and I sure can't see anything anywhere else that looks like it could be a MAP sensor.
:).
 

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The Baro sensor is part if the MAF.
What? No... The MAF sensor is actually pretty rudimentary. Two resistors in a measuring bridge, one of a calibrated value, the other one is a hot metallic wire that gets cooled by the mass of air blowing past it, so it's resistance changes proportional with the mass of air (velocity). The temperature of intake air is taken at the air filter box.
There is no pressure reading in the MAF.


A more detailed explanation:
MASS AIR FLOW SENSOR (MAF) (autoditex.com)

Operation of MAF is based on the principle of constant temperature. Heated platinum wire, suspended in the engine’s air stream (3), is one of the legs of a Wheatstone bridge. Constant temperature of approximately 100 ºС is maintained by increasing or decreasing the electrical current flowing through the circuit while the incoming airflow cools the wire.
By increasing the airflow, platinum wire gets cool and its resistance decreases. The Wheatstone resistor bridge is asymmetrical and a voltage appears which is submitted to an amplifier and directed to raise the wire temperature. This process continues until the temperature and resistance of the conductor does not lead to system balance. The current range is 0.5A – 1.2А.
This current also flows through a calibration resistor and forms a voltage drop which enters the onboard controller for calculation of the quantity of the injected fuel. Changes of temperature are compensated by the resistor (4), which is a platinum ring, suspended into the air stream. The temperature changes simultaneously influence both the heated resistance conductor (2) and the temperature compensation resistor (4), and thus the Wheatstone resistor bridge remains balanced.
During operation the platinum wire inevitably pollutes. To prevent the pollution after turning off the engine, the wire is heated to a temperature of 1000 º C for 1 sec. Thus all the dirt stick to the wire is burned. This process is controlled by the onboard controller.
 
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My note: Using an oil separator on the PCV hose that goes to the intake air hose, will extend the life of the MAF sensor - because less oil will be burned on that hot wire.
 
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There is no hot wire in the MAF type used on the Delta engine. It is a conductive film (layer) on an insulator (silicon substrate). Wire based MAF is 1980s technology. Crankcase ventilation gases enter manifold downstream of MAF (that sits between air cleaner and surge tank /throttle), so deposits are negligible. Most film MAFs die from ageing (cracks in the film), not from contamination.
DOHC/I4 engine uses MAP, V6 uses MAF.
 

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At least in US looks like it's wire type, same like on BMW 2.0-2.5L from 2000 era:

Auto part Circle Metal Font Fashion accessory





This is a film type:
 

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in some models the MAP sensor is combined with either the MAF or Air Temp sensors
The air temperature sensor is often combined with whatever sensor is used to measure the air entering the engine. So the IAT sensor is usually built into the MAF or MAP sensor.

I've never, ever heard of a MAF sensor having a baro sensor combined with it. I'm not saying that there isn't some engine out there with that arrangement. It's just not one I've personally come across, so it wont be a Hyundai engine.

If I helped you fix it, why not...

Your support is greatly appreciated
 
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