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Discussion Starter · #1 ·
Here I want to share a successful experience about using a Porsche Piwis cable from China to troubleshoot MAF on 996T Turbo.

Begin I believed the car had a faulty mass air flow sensor. Turn out I was right. Replace the MAF and the issue is fixed. Below is the process that I determined the issue:

Fire up Piwis Durametric cable and find three parameters:

Mass Air Flow (HFM)

Mass AIr Flow (KG/H)

Hot Film MAF

Set the parameter Mass Air Flow (HFM).

This parameter should work in positive numbers. When you are running low speeds like 10mph, the value should be less than 100. When you increase speed it should increment. If you were running at say a constant 60mph. Then you should see around 100.

As soon as you open the throttle up, the numbers should start to shoot up. It would be normal to see something like this.

RPM 3500 maf = 285

4000 maf = 556

4500 maf = 800

However when you really start getting on boost, you would expect the numbers to be up in the 1300-1500 range etc and as soon as you come off boost, they should drop back.

Make sure you set the Throttle Plate Angle parameter so that you can record this position. So when you are at Wide Open Throttle (WOT) you should see value of TPA around 99.6 etc. At this point, the MAF should be around 1300-1500.

A MAF that is not working well will give inconsistent results. Typically, you might see the above results, but then you will see minus numbers, uneven numbers.

As long as you see something like I have described above, your MAF is fine. Don’t compare the exact figures I gave you above e.g. if you are 50 or 100 higher/lower, that is not an issue. It is the consistency that you should look for.

I got solid “3″ at Mass Airflow (HFM) and changed by RPM Mass air flow.

Hot film Maf is also very solid.

Run up to 6500 on boost and get the real-time data.

In my case, the MAF sure does look dead as a dodo.

I replaced MAF, please see below logs.

So theoretical if one value of MAF log is constant (solid) its means bad MAF. Get the MAF replaced and now car running good


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