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Model specific boards => Golf mk2 => Topic started by: Bigdunc on 02 November 2011, 16:38

Title: Testing a maf unit
Post by: Bigdunc on 02 November 2011, 16:38

As title says,

Need advice on testing my maf unit, I read about the resistance test in the Haynes manual

Now I get a good reading on pin 2-3 and when open flap the reading does fluctuate

Now on pin 1-4 I get a quick reading for a second when conect the multimeter then after that I don't :(

Could this be a sign I have a dead unit??

Any more advice maybe testing conector on the car loom

Thanks in advance

Title: Re: Testing a maf unit
Post by: Wayne on 02 November 2011, 23:47

Does it run better with it disconnected.

Title: Re: Testing a maf unit
Post by: Bigdunc on 03 November 2011, 10:02

The sensor is built in to the maf, the car won't run without the maf plugged in surely

Title: Re: Testing a maf unit
Post by: the flying mantuan on 03 November 2011, 19:57

Dunc,

if its any help I disconnected my AFM when doing some work on my digifant and forgot to plug it back in. Car would turn over briefly start and then die. 10 minutes of head scratching later I noticed it was not connected, plugged it back and the car started first time.

 :smiley:

Title: Re: Testing a maf unit
Post by: Wayne on 03 November 2011, 23:55

Quote from: Bigdunc on 03 November 2011, 10:02

The sensor is built in to the maf, the car won't run without the maf plugged in surely

It should do, if it runs better it is a sure sign it is knackered.

Title: Re: Testing a maf unit
Post by: clipperjay on 04 November 2011, 15:55

Quote from: Wayne on 03 November 2011, 23:55

Quote from: Bigdunc on 03 November 2011, 10:02

The sensor is built in to the maf, the car won't run without the maf plugged in surely

It should do, if it runs better it is a sure sign it is knackered.

Wayne is right the car should go into a safe mode i.e a stock map of what the sensor should be doing if that part fails.
So by unplugging it the ECU should just kick in a standard heat mapp to compensate, if not more rich to be on the safe side of things.

Title: Re: Testing a maf unit
Post by: Bigdunc on 04 November 2011, 19:54

The sensor is in the unit do I just take top off maf unit and unplug the 2 white wires?

Having serious problems getting my golf started its been sat on road for 2 weeks now :(

Title: Re: Testing a maf unit
Post by: Bigdunc on 04 November 2011, 21:56

ok just thought, when i went to have my fuel set the guy said he couldnt get it very accurate and it was comming out to lean so could this also be a problem with the maf(afu) unit?

Title: Re: Testing a maf unit
Post by: clipperjay on 04 November 2011, 22:22

Well unplug the thing it will run ok in the winter its the summer when it overfuels the most to compensate for hotter ambient air flow temps.
The winter time is the only time you should run it without a MAF (more oxygen denser air flow to burn up fuel) for three months or can't be arsed to change it on time  :grin:

All you have to remember is go for a genuine VAG part (Usually Bosch) when it comes to MAF I've tried loads of aftermarket and they are sh!t! Waste of money!
Reasons for a MAF is purely to save on fuel on idle and it helps to stop unburnt fuel going to the CAT and killing one.

Remind me what engine this is on again?

Title: Re: Testing a maf unit
Post by: Bigdunc on 06 November 2011, 10:09

It's on a mk2 8v digi, I've never been able to start engine with the mass air flow unit unplugged,
But I notice the air flow sensor is built in to this unit, along with the fuel mixture screw,

I shall try unplugging the unit and see if car will run but I never had any luck befor without it plugged in