Thread: MAF questions

I think you have pretty much answered your own question. 1x new VDO MAF on the shopping list.


Its not money wasted if you have never changed it before and if the kms are up there....

vote 2 for replacing with vdo unit

Originally Posted by simpin68

My td5 is behaving badly and surging when I floor the accelerator. At 3/4 throttle it is fine. Following advice from this forum I unplugged the MAF and wow the car ran like it was new again. I cleaned the MAF with contact cleaner , plugged it back in and the car is back to surging again.

My questions are:

What does it actually do?

Why does the car run better without it?

Does this mean it is stuffed or is it masking something else?

Where is a good place to get a new one?

Hi Simpin68,
I think the other answers are:


What does it actually do?
Measures the rate of air inflow at / near the air filter, and provides this info to the engine ECU

Why does the car run better without it?
I think that it would not do so if the MAF was OK.
So the fact that it does indicates that it needs replacing.


Cheers, AndrewMilne

Originally Posted by turbopsi

I think you have pretty much answered your own question. 1x new VDO MAF on the shopping list.


Its not money wasted if you have never changed it before and if the kms are up there....

I just had a quick look at prices and I can see why you wouldn't get an original.

Wow

According to other threads on here, the general consensus is Siemens/VDO are OEM.

I bought the VDO unit around 3 years ago and no issues.

Originally Posted by simpin68

Why does the car run better without it?

The ecu has default values so it can run without a MAF. Not as good as getting real values but good enough to get home.
If it runs better without it, the MAF needs replacing. So it also helps to fault find.

Speaking from experience......

Your MAF is measuring the the amount of air entering and mixing with your fuel. Too much and it restricts the airflow, too little and it adjusts the fuel flow. All done (I stand to be corrected here) by your ECU.

If the readings from your MAF are wrong (either way), it will trip the ECU into a limp home mode which will restrict RPM to about 2,500 from memory. It does this by shutting off fuel and thus, the turbo doesn't cut in.

You now have a TD5 with bugger all power!

I cleaned mine a couple of times but the positive effect you have noticed is temporary. Just bite the bullet and replace it. It's about $240 and 2 minutes. You wont have to worry about it again for a number of years.

That's my 2 bob's worth..... I've read sooo many posts here about cleaning etc and really, its just not worth the trouble

Just got a new VDO/Siemens (made in Germany) MAF from Karcraft in Sydney ... $185.60 + $11 postage.