MAF: What's missing from this picture?

MAF: What\'s missing from this picture?



That's Aaron's MAF sensor. (The former Sprocketsmobile.)

Error code: "MAF sensor implausible result", or something like that.

Isn't there supposed to be a resistor of some kind between those two copper terminals? If you look closely you can see there is a sort of diagram molded into the plastic, showing what appears to be a resistor between the two terminals.

The symptoms match a "limp home mode", and this is the first time I've seen an ECU say, straight up, that the MAF is faulty. Seems pretty cut and dried.

If there is a resistor missing, what value is it supposed to be? A 50 cent Radio Shack resistor would be much better than buying a $200 MAF sensor.

-mickey

p.s. I'm also a little curious about where the resistor went. Kind of scary!

Re: MAF: What\'s missing from this picture?

Nothing is missing. I just pulled mine out (perfectly good MAF). It doesn't have one.

Re: MAF: What\'s missing from this picture?

Hi,

Mine's a '99 A4 and the MAF looks exactly like your picture. Empty contacts and a picture of a resistor.

I think the turbo would have objected to a resistor had it been fed one.

Dan

Re: MAF: What\'s missing from this picture?

Hmmm. That's not good news.

Too bad the ECU doesn't tell you exactly what "implausible" means.

-mickey

Re: MAF: What\'s missing from this picture?

Dude, just set it up so that the MAF wire always reports maximum airflow and pull the sensor. Now you're talking a smoke show. At least you won't have to worry about the car running lean

Coop

Re: MAF: What\'s missing from this picture?

As if we didn't need more clarification..............drumroll..............I am holding my old MAF in my hand and it looks exactly the same. By the way someone asked the serial number in another thread, and mine is PBT-GF30. Everything is written in German, it is a Bosch part, there is a code of 816 in a circle to th right of the "made in germany" logo. My new MAF is inscribed in English.

Re: MAF: What\'s missing from this picture?

Bora TDI that's just the group parts #. If you look on the outside of MAF housing you'll find the same #. What is important for this research is a # that will be something like 962 13 1B or maybe 183 19 2A What are some other series out there?

Mickey, thank you so much for that pic. I've been trying to post mine but have had nothing but frustration and gave up.
That is the first step in MAF failure I believe. I believe it is corroding or burning up. My newest one lasted a month. I don't know if it's related but I found it missing after a series of heavy rains and extended driving on the hi-way. I know that's weak but it's something to chew on.

Re: MAF: What\'s missing from this picture?

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by 2GreenTdi's:
Mickey, thank you so much for that pic. I've been trying to post mine but have had nothing but frustration and gave up.
That is the first step in MAF failure I believe. I believe it is corroding or burning up. My newest one lasted a month. I don't know if it's related but I found it missing after a series of heavy rains and extended driving on the hi-way. I know that's weak but it's something to chew on.<HR></BLOCKQUOTE>

I believe in a couple of other posts, you mentioned you had a wire or resistor on your new MAF and now it is gone. Where did it go? Only logical answer is that it is sucked into the intake, right? <Gulp!>

Mickey, my MAF is exactly like yours--blank terminals.

Re: MAF: What\'s missing from this picture?

It's not mine. It's Aaron's. This pic is from tonight's episone of "mickey's garage."

My original MAF sensor is A-OK, thanks! A little TOO good, actually. Too much smoke.

-mickey

Re: MAF: What\'s missing from this picture?

Thanks for the consensus everybody! I guess I'll be out buying a new MAF now anyway. Lets see . . . who had that group sale again . . . ?

Thanks!

Aaron

Re: MAF: What\'s missing from this picture?

Just a hunch on the MAF resistor. I am sure that the wire grid which air passes over and cools is a very high precision device, and that if it does not quite fall into tolerance after manufacturing, this resistor port gives them one more chance to "trim" the resistor wire, or perhaps scale the device readings to fall into proper tolerance range. Therefore, they salvage more parts from the batch of MAF's produced.

If I had a MAF with a resistor on it, I would feel that the part was probably at the extreme range of being "within specs". On the other hand, with the resistor in, the part was probably recalibrated by a human, and if they took the time to properly trim it by adding a resistor, it is probably calibrated within tolerance.

Just my theory on the resistor thing.

Also, a while back someone posted a link to the german site which had a PDF on the MAF, talking about the hot-film anemometry. Good reading for the EE's. The same company has an office near Detroit, and maybe we should covertly try to make a friend over there and weasel some info. Any opinions?

Re: MAF: What\'s missing from this picture?

I'mm thinking that perhaps the 'missing' component may be used to alter the MAF so it may be used for another application. My 2k MAF does not have this component either.
As an aside, I just noticed that Venom performance shows, what appear to be, some sort of electrically adjustable MAF that are 75mm. It may be too oversized for our app., butmay be worth looking into. Note: it would require substantial adaptation for our 65mm piping, but would also remove the largest (in in/H2O) restriction before the turbo intake. BRAIN Cramp!!!! Could the problem w/our MAF be related to the rapid rise in intake volume (VNT), cooling the thin film so quickly that thermal fatigue is causing the creeping failure most of us w/ failures, are seeing? O'h APR (Audi Perf. Research) also carries bigger MAF I think. Good chance there since their family you know. Any more info on adapting the earlier MAF to the A4's?

Re: MAF: What\'s missing from this picture?

There's nothing missing - that's a MAF for a TDI. If it were a MAF for a 2.0 gasser, you would find a thermistor at that location, used by the ECU to measure intake air temperature (IAT). If you look at a wiring diagram, you'll see this. The TDI measures IAT after the intercooler, so one on the MAF would be useless.

I suspect that the gasser MAF would work fine in a TDI, but obviously not the other way 'round.

Re: MAF: What\'s missing from this picture?

OHHHHHHHHHHHHH!!!!!!! I see, now! OK. That makes sense. It would also explain why there are so many wires hook up to what is really just a "variable resistor." For ease of manufacturing they probably use a common MAF plug and harness for both TDI and 2.0.

Sorry, Aaron. Looks like you'll be making a purchase. That STILL might not solve your problem, but I'm fresh out of ideas. Perhaps the OBD-II is actually "diagnosing" something for a change, eh!

If you want to make another road trip out here we could install my MAF into your housing and see if it breathes new life into your car. (Should have thought of that last night, actually. But it was late.)

-mickey

Re: MAF: What\'s missing from this picture?

Did anybody catch this thread on MAFs?
http://forums.vwvortex.com/zerothread?id=89460

Hopefully it means that "improved" MAFs are starting to enter the supply chain.

Re: MAF: What\'s missing from this picture?

My theory has always been that there was a bad batch out there. For the record, these are failing in Audis, on both 1.8t and V6 twin turbo cars.

I have a fresh order of MAFs on hand if anyone needs em, see the classifieds.
I am also looking into a lower cost solution to our problems (please don't ask, I can't get into it just yet but I will post when I'm ready).

Re: MAF: What\'s missing from this picture?

msuave, the thermistor theory is good and I guess the dealer would throw one in my TDI if that's what they had. However, within a month it's vanished and there aren't many options for which way it went.

I don't appreciate amatuers putting parts on my car that might have adverse effects on it's durability.

Re: MAF: What\'s missing from this picture?

in the latest C&D, there was a tuned up MB AMG car that toasted it's MAF on the first or second run.. (presumably a Bosch unit as well?)

it is good to be precise, but not at the expense of being fragile.

Re: MAF: What\'s missing from this picture?

http://www.kemparts.com/tt06/tt06.html

Re: MAF: What\'s missing from this picture?

I read that about the MB.
Pretty embarrasing, and all for a MAF...

Re: MAF: What\'s missing from this picture?

This article is good but realize that MAFs can fail with no codes shown at all.

One thing I wonder more about is temperature - the MAF in my car was pretty hot, as was the rest of the engine when I removed it. And most of the MAFs going bad seem to be in turbo cars. Perhaps trying to keep heat off the MAF would extend its life?

Re: MAF: What\'s missing from this picture?

I posted this in another thread, but I'll post it here just to spread it around. I checked the MAF on my 2002 Golf GL and that wire was not there, nor was it branded. Pictures to come in a few days.