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When MAF's go wrong!!!!

Menace

Hockenheim
Joined
26 May 2009
Messages
699
Hi guys,

Sounds like a crappy TV show right? So here's my little tale.
I usually work in Central London, so don't get to drive my car as often as i'd like, on some occasions i work in our offices in Chiswick or Reading.
So last week i was working in Chiswick, i got quite excited, first thought was, i get to drive to work, woohoo..
Monday morning, get in the car, ready to grab the shades as it's been real hot of late and...and...Um, nothing, engine turns over, goes to start then dies,
had to get to work so i head off for the day, absolutley s@#$%ing my boxers. I spent the following evening trying and searching the internet for more options to no avail.
I had to meet friends on saturday and fairly fed up, i decided to book the car in on monday morning and have a play on sunday.
Whilst out on saturday night, the other half sends me a text to say that she has researched the problem it she thinks it is the MAF, no two points here, the MAF was on the list to check and she is just not a car person, just like Googling problems.
Anyway, sunday afternoon, pull the MAF plug, as she said, lol, guess what?? You know the rest..
New MAF being fitted today.... Not the cheapest things in the world either, once you find the suuitable one for your model but i'll be paying with a smile, as it has been a stressful week.

Regards

Vinny
 
PS, had a lovely drive to work all week in my mum's KA :x
 
MAFs - they certainly can be bastards! :lol:

I clean mine once a month
 
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.
 
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...
 
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Does a turbo not have a maf then and does the map do the same job/suffer from the same problems?
 
chriscoates81 said:
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Does a turbo not have a maf then and does the map do the same job/suffer from the same problems?

A turbo has a MAF (Mass Air Flow) sensor and a MAP (Manifold Absolute Pressure) sensor; the Bosch MAF is a "hot-film" type sensor which has a voltage applied to it to heat the element to a certain fixed known temperature, air then passes over it (from the air intake - the MAF sits in the air flow just after the air-filter) which causes a temperature differential across the measuring fields of the element - the ECU then interprets this as the mass of air per second (g/s) available to the engine - the ECU then fuels accordingly.

The MAP sensor simply measures the amount of air-pressure (i.e. atmospheric pressure + boost pressure) entering the throttle body - it sits in the air flow just in front of the throttle body. N/A cars don't have MAP sensors.

MAFs due to the slightly delicate nature of their construction can fail/degrade (which is why I give mine a good clean with IPA once a month), whereas MAPs are a more robust device and are less prone to failure.
 
DeathStar said:
chriscoates81 said:
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Does a turbo not have a maf then and does the map do the same job/suffer from the same problems?

A turbo has a MAF (Mass Air Flow) sensor and a MAP (Manifold Absolute Pressure) sensor; the Bosch MAF is a "hot-film" type sensor which has a voltage applied to it to heat the element to a certain fixed known temperature, air then passes over it (from the air intake - the MAF sits in the air flow just after the air-filter) which causes a temperature differential across the measuring fields of the element - the ECU then interprets this as the mass of air per second (g/s) available to the engine - the ECU then fuels accordingly.

The MAP sensor simply measures the amount of air-pressure (i.e. atmospheric pressure + boost pressure) entering the throttle body - it sits in the air flow just in front of the throttle body. N/A cars don't have MAP sensors.

MAFs due to the slightly delicate nature of their construction can fail/degrade (which is why I give mine a good clean with IPA once a month), whereas MAPs are a more robust device and are less prone to failure.

Ahh i see. Is maf a bit of an arse to get to then as i feel it should become part of the cleaning ritual.
 
IPA really good stuff !! Indian Premium Ale , I just love it. Will try it on the MAF mate !!!

Let's get serious again where do you get the IPA Jules ?
 
chriscoates81 said:
Ahh i see. Is maf a bit of an arse to get to then as i feel it should become part of the cleaning ritual.

No, not really - you just need the right security torx bit to undo the 2 bolts used to attach the MAF sensor to the air-box (it sits in the tube that extends from the rear half of the air-box ... on a turbo anyway, might be different for a carrera?)

@Steph - spray can of 99.9% IPA from Maplins for £7.99 :thumb:
 
You just spray it on the element and leave to dry or do you wipe it with coton or tissu aftetward ?
 
quattrosteph said:
You just spray it on the element and leave to dry or do you wipe it with coton or tissu aftetward ?

Just spray the sensor elements using the straw provided with the can - the pressure of the spray in conjunction with the IPA cleans the elements. Don't touch them with a tissue or cotton bud ...
 
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Yes I know but I will be able to run just off the MAP sensor but it will be a 5 bar one that we use with the standalone ecu :D Might even run a woosh bang dump valve then for good measure !!!!
 
JohnnyDangerous said:
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Yes I know but I will be able to run just off the MAP sensor but it will be a 5 bar one that we use with the standalone ecu :D Might even run a woosh bang dump valve then for good measure !!!!

Ah I see ... :thumb:

Not so sure about the dump valve though ... :nooo:
 
DeathStar said:
chriscoates81 said:
DeathStar said:
JohnnyDangerous said:
Cant wait to get my new ecu so I can run a MAP sensor and get rid of the MAF.

You've already got a MAP (Manifold Absolute Pressure) sensor on a turbo - it sits on top of the Y-pipe just before the throttle body ...

Does a turbo not have a maf then and does the map do the same job/suffer from the same problems?

A turbo has a MAF (Mass Air Flow) sensor and a MAP (Manifold Absolute Pressure) sensor; the Bosch MAF is a "hot-film" type sensor which has a voltage applied to it to heat the element to a certain fixed known temperature, air then passes over it (from the air intake - the MAF sits in the air flow just after the air-filter) which causes a temperature differential across the measuring fields of the element - the ECU then interprets this as the mass of air per second (g/s) available to the engine - the ECU then fuels accordingly.

The MAP sensor simply measures the amount of air-pressure (i.e. atmospheric pressure + boost pressure) entering the throttle body - it sits in the air flow just in front of the throttle body. N/A cars don't have MAP sensors.

MAFs due to the slightly delicate nature of their construction can fail/degrade (which is why I give mine a good clean with IPA once a month), whereas MAPs are a more robust device and are less prone to failure.

Which is why any car with a MAF will have to run a recirculating dump valve (diverter valve) as a vent to atmosphere BOV loses some of the air that has already been measured , therfore the ECU would get somewhat confused as its adding fuel for X amount of air and theres only Y amount actually there :bye:
 

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