Checking MAF without diagnostics tool

[Kogi]

Guys,

Turbo fluttering, limp effect after a tuning and power loss - leads me directly to a conclusion that it might be a crappy MAF sensor that playing a bad game with me ....

I have ordered a VAG-COM cable from the EBAY store and still did not get it, however I would like to check my MAF today , and maybe go to my workshop to show them the problem afterwards ..

The MAF sensor sensor should convert the amount of air into a voltage, means that I can disconnect a plug and connect my Volt-meter and measure the voltage within opening a throttle.
Will it work ? what should the voltage in case of normal operation of the MAF?

thanx !

 

[cordobabrendy]

try disconnecting the maf temporarily, if the car runs better you know you have a duff maf sensor.

 

[Kogi]

You are the expert ..... but doesnt it confuse the ECU ? i thought the ECU needs some info from the MAF in order to calculate a fuel amount to be injected into the engine, also the ECU shall manipulate with other components based on the MAF signals ... ??

thanx !!!

 

[cordobabrendy]

Temporarily this will prove the fault out , especially when the maf was giving degraded readings to the extent of noticeably bad running. Disconnecting the maf makes the ecu eventually learn to run on stock perameters.

 

[Kogi]

maybe bypass the MAF and re-program the ECU ...

Going downstairs to check it !!!

thanx for the advice !! I'v really got sad .. my car behaves differently from day to day, seems like someone remapping it every night and I can not recognize my car the day after .... completely weird situation ...

 

[DPJ]

Temporarily this will prove the fault out , especially when the maf was giving degraded readings to the extent of noticeably bad running. Disconnecting the maf makes the ecu eventually learn to run on stock perameters.

Without the MAF reading, the ECU does it's best with the readings it gets from the MAP sensor. But because it doesn't know how much air is going in, it doesn't know vehicle speed is right etc. Not ideal.

 

[cordobabrendy]

This is a temporary solution as it will probably slightly overfuel which in the long run isnt good for the cylinders and cat.

 

[longman]

Where abouts are you Kogi? I have VAG-COM if you would like some help?

 

[DPJ]

Where abouts are you Kogi? I have VAG-COM if you would like some help?

I think that might involve a trip out of the country for one of you.

 

[longman]

I think that might involve a trip out of the country for one of you.

He he....Did get that impression but thought i'd ask just in case.

 

[Kogi]

OK !! Ivgot back from experimental ride !
Disconnected a power plug from the MAF and immidietely got TCS warning lamp turn on ..

The results: no fluttering .... and no POWER anymore , connected back the MAF , the same story .... I can not feel a power pop at 3500rpm which should occur after a tuning ( I felt it before !) .... The car just keep running on 180HP maybe a bit more ... sooooo ... where is my 220HP promised by my workshop ?

Does ECU capable to reprogram itself somehow ?

thanx .. !

P.S. My location is Middle East (Israel) far far away ..

 

[longman]

Dave, you were right mate!!

Kogi, only wish i could help you with a diagnostic test.

Now you have done that, I would suggest resetting your ecu so it forgets your last drive with no MAF connected. You can search for how to do this as there are lots of posts about it.

Then, try driving again, if there is still a problem. It will hopefully flag up a real fault again that can be checked with VAG-COM. Is there anyone near you with it?

This might even

 

[Kogi]

Yeah .. will give an attempt to reset the ECU (disconnecting negative battery cable for a while) ...

The closest VAG-COM cable can be found only at my workshop, where my car has been tuned ... and its around 100km trip ... Well, I guess I have no choice and pack my bags and finally visit the guys who spoilt my car. I think the car just lost a boost somehow, I can not hear a loud voice from my open filter, prior to a MAF mess , it was generating some very interesting bawl - similar to vacuum cleaner ... now its just sucking air like an old man ...

Hope to get my VAG cable soon and get myself into the car's brain and understand WTH is going on ...

thanx for all you help and support

 

[longman]

Its probably best to go back to them anyway. Just explain that there is an issue and perhaps they need to have a look at it.

Good luck, I would be interested to hear the outcome Kogi!

 

[cordobabrendy]

after plugging the maf back in, try disconnecting the battery and leaving a door open for a min or two, this will reset the ecu and see ghow that goeso too. 60k round trip is nothing, my local revo dealer involves a round trip of 120 miles maybe more and I only live in a small country! haha

 

[Kogi]

Who said broken MAF ?!

Seems like it was the problem, after visiting my workshop, they have connected me to some weird diagnostics monster machine from Bosch and the guy told me that I have strange reading from the MAF sensor.
He said the readings are not linear in a full opened throttle (kick from 1000 to 6000rpm) or something, also we saw some error "Air filter low signal ... "

We've replaced the MAF with the new one and now it feels better, but I still not convinced, not sure that I'v got a full power ....

Next week I'm gonna receive a VAG-COM cable and get my readings ... any suggestion what I have to measure in order to have an estimate picture of how much power I currently have ?

BTW: My boost raises up to 18psi !! (Tested with the boost gauge)

thanx !!

 

[cordobabrendy]

I'll refer you to the very first post after your initial one regarding the problem

 

[Kogi]

Ok, my workshop claims that will cost me around £100 (new MAF) !!!!
Does it sound like a reasonable price or I can find something (Bosch made) cheaper ?! any links to the on-line shops ?

thanx !

 

[bbm]

Ok, my workshop claims that will cost me around £100 (new MAF) !!!!
Does it sound like a reasonable price or I can find something (Bosch made) cheaper ?! any links to the on-line shops ?

thanx !

It is the same price in Bucharest / Romania