How to test MAF/Boost/EGR etc using VAG COM

[Loofer]

It's all nice and cosy checking for stored faults using VAG COM but I would like to know how to test the above and more using VAG COM.

Can't find much info on the RossTech site or the VAG COM manual.

In particular, it's myy car which has seen a siginifican drop in fuel efficiency. It's been consistent for over 6 months but deteriorated in the last 2 months.

Please can somebody write up a dummies guide and info as to what measurables/values we should be looking for based on the particular engine.

Or you could just point me in the right direction as to where I can find comprehensive instructions.

:o

[Col]

It all depends on what you need to look at.

The key function in vagcom that allows you to do this are the measuring blocks. These combined with graphing and saving the results (whilst on a run) are the most helpful.

If your down on performance, look at the boost and maf measuring blocks. These are quite helpful as you are provided requested (via ecu) vs actual (as measured) to enable a comparison to be made.

[Loofer]

It all depends on what you need to look at.

The key function in vagcom that allows you to do this are the measuring blocks. These combined with graphing and saving the results (whilst on a run) are the most helpful.

If your down on performance, look at the boost and maf measuring blocks. These are quite helpful as you are provided requested (via ecu) vs actual (as measured) to enable a comparison to be made.

Thanks... the exactly the kind of thing I want to do.
Any chance you can provide instructions on how to do this or tell me where I can find them?

Thanks

[Col]

As with most software, play about about with it to learn.

But basically, log into whatever module you need i.e. engine then select measuring blocks and then cycle through the channel numbers.

As you do this you'll see various values and usually a key / explanation of the readings you are observing.

[Loofer]

Well for the first time, I've used my VAG COM for logging.

Didn't cycle through all the channels but measuring block 003 appeared appropriate to measure MAF.

Still not sure exactly what I should be looking for or how I should perform the test.

I've plotted a graph in the spreadsheet so do please have a look at the attachment.

It appears the MAF actual meets the MAF required on most occasions (though maybe not sufficently)... but I'm not brilliant at anlaysis. Does it look like a duff MAF?

At the time of logging... The engine was warm and I drove it for about 30 secs from 1st gear to 3rd gear which is where I peaked at 2750rpm.

What other channels should I try?