New MAF questions
 

So I got the $93 Buyautoparts MAFand the Durametric numbers are great. The FRA and RKAT numbers and voltage are all right on the money,where with the old MAF the numbers were pretty far off. But the mass air flow still is off.The spec is 15 kg/h +/- 1.25, the old MAF read around 13 and the new reads about 19. I also got two error codes, MAF reading above upper limit and air intake temp reading above upper limit right after I installed the MAF but they haven't come back since driving around a bit.

Now it has a slight drivability problem. The idle is hunting, almost stalling when I first start the car but it gets better as it warms up. And the power felt down a little but it did seem to improve after a couple of full throttle runs.

So is this just the DME adapting to the new MAF or something else?

When I installed my new MAF I had unplugged the battery to clear any codes I had thrown. Might be worth a shot if you didn't do that already?

I think the clear codes function of the Durametric does the samething.

Good point..I knew it would clear the fault codes but wasn't sure if that was the same as resetting the ecu (I thought that's what a disconnected battery did but I may be way off)
When I swapped out my MAF and went for a drive it was night and day difference, no idle stumble or issues at all. Really woke the car up again instantly..I'm well over a couple thousand miles now with this cheap eBay MAF, someone with more experience with these cars I'm sure will chime in and help!

Well I diconnected the battery and I still have the hunting idle right at start up which gets better as I drive. I'll run it for a couple of hundred miles and see what happens.

The Durametric will clear the codes but disconnecting the battery will clear the codes AND the ECU learned parameters thereby forcing the ECU to start with the default maps and then learn again all over. Either way, the ECU should learn to adjust for the new ECU but disconnecting the battery is an easy and free approach to reset the ECU and let it learn from scratch.

Hunting idle is most often an intake air leak. The car runs lean under high vacuum which does not affect MAF readings.

I don't think its a vacuum leak because with the old MAF I had a rock steady idle.

A dirty throttle body will cause a hunting idle.

You should disconect the batterie for 10 minutes
switch on the ignition without starting the engine for 3 mins
switch off the ignition
and now you can go, your DME is going to learn the new values from your new MAF

When I replaced the maf the idle was rough for a short 3 minutes. And it took the car a couple hundred miles to learn and adopt to the new maf. I did reset using dura metric. I'm still not happy with the eBay maf as I feel it is not the regional power. However it might be some other issue. So going to do a compression and leak down. Then maybe return this maf and get the oem part.

Well this morning from a dead cold start, the car runs perfect. No hunting idle. I guess it just had to do an adaptation from cold to sort out the problems.

Back to square 1. The idle still hunts on a hot start up and it has thrown a MAF code again. I think I'll give it a week and then return the MAF if I still have problems.

I'm thinking of trying the Pelican Maf. Is the Pelican MAF the same one sold at Porsche dealers or just the same Bosch part?

Disconnect the MAF and run the car. If your idle smooths out, replace the failed MAF.

I believe Pelican sells the OEM part that works well. I have not tried one.

Alright, I'm returning the Ebay MAF. Today, it only got worse, I drove it over 75 miles, hoping it was just an adaptation problem but the idle is still hunting, the power is way down, its surging at 60-90 mph, and when I launch, it has stalled a couple of times, I have to rev to 3k + just to get off the line, with backfiring and honks from drivers behind me.

I get a stored MAF code at every startup and the straw the broke the camels back is a CELlight. I put the old MAF in and the car runs fine.

I don't know if its just a bad unit, but I don't care. I'm going to try the Pelican MAF and see what haappens.

You do know I have a table of Bosch MAFs on this page at the bottom. They are know to work, after all, Porsche buys em.

Thanks, I'm going to try Autohauz for $172.

Having owned Fiats, Alfas, Triumphs and Lancias - you must feel right at home with the way your boxster is currently performing ! :) Seriously, though, it may be that you were either sold a defective sensor or someone on the other end didn't cross reference it correctly.

Except for the Triumph, I had pretty good luck with the other cars. Boxster isn't too bad.

Anyway, the MAF is not a Bosch part, or if it was, its reman, because it has no Bosch numbering on it. I'm going to try a genuine bosch and see what happens.

Update- Buyautoparts refused to refund the purchase price, but sent me another MAF. This one seems to be working fine. Air flow is within spec right around 14 kg/hr at 700 rpm, rock steady idle, smooth power all the way to the redline.

The only thing I've noticed is that the RKAT adaptation value is right around +2. Is that a correct value? Anyone know the spec for RKAT?

Even though I felt the after market MAF was learning to adapt to the car, the power at the 3k= rpm that kicks in was missing. Buyautoparts would not refund my money either. Their return policy does say that they will replace the part (not refund). The guy at the other end of the phone wanted me to take it to a shop, do the diagnosis on the car and prove that the second MAF they sent me was bad. Which was ridiculous. Speaking to another person seemed do make some progress. I ordered the original Bosch part and dropped the price by 30 bucks. Still not low as ********************************az @170.

But no more aftermarket on things like this for me. Too much trouble trying to save a few bucks and all I went thru was frustration. Others may have a luck with this but not me. Now waiting to test the OEM MAF.

Interesting, when talking with customer service, the guy said they've NEVER had complaints about the MAF, when apparently, at the same time, you were having problems with your MAF.

The first guy wasn't of any help. The second did say that they have had good success rate.

The aftermarket I received is not malfunctioning per say - no errors or CEL light. It was very sluggish initially and then steadied out. But I'm totally missing the power kick at the 3k+ rpm. Which was there with my bad original MAF even though it was giving me error codes. Doesn't drive like an S. More like my minivan!

So I guess if I felt this was acceptable then they add me to the success rate statistics.

One thing my mechanic discovered is that you can get a MAF error and it's not really the MAF, but one or more of the 02 sensors that is fouled and it's throwing off the computer.

Your car is approaching 13 years of age. If you've not replaced the 02 sensors, I'm betting they're due. This might fix your problem.

BTW, I was not experiencing CE lights or any performance issues and I replaced my 02 sensors because I figured they needed replacement after 85k miles. The difference in power and performance was very noticeable. It was worth the $450 I spent on four new ones (bought mine from OxygenSensors.com). They've come down in price a lot since then...

http://www.oxygensensors.com/catalog.php?&pkey=1364385

Or is the strategy to replace the forward two since the rearmost pair only do some checking of the cleaned up exhaust? Mine got lazy at 60k or so but I only replaced the front ones. I used Bosch who makes em for Porsche and because there would be no doubt they would be the right ones.

I received a Bosch maf for replacement to the aftermarket that was not doing its job. They promised me it is a brand new one. The label seal on the box was cut and the maf was wrapped in some kind of oily paper. And then they stuffed brown packing paper into the Bosch box itself. And just as I had a gut feeling, the resistor was bent due to the way they packed it. I recall receiving the aftermarket ones on thermocol box like packing. Aren't the oem supposed to be as well? They are sending me another but it's been so frustrating and has been a waste of their time and money and mine as well.

What I advice fellow owners is that go for the oem part when it come to maf especially. The after market is 109 and Autohauz is currently selling the Bosch for 170. You will be chasing so many collateral issues potentially with the aftermarket. But, it has worked for some like JD. IMO it's not worth saving the 60 or so bucks.

Bala, if I had to do it again, I would definitely go with OEM. My second aftermarket seems to be working ok, the numbers have stabilized and they are pretty much on the money, and power seems ok, but in hindsight I would have gladly paid $70 more to avoid all the hassles I've gone through.

Will exchange of the two rear sensors do any difference to performance if they are worn out? I was under the impression that they only did some follow up on the efficiency in the forward cats and made no change the A/F ratio. Would be interesting to know before I pull the trigger on a new set of O2 sensors.

For the record, I neither advocate nor discourage the use of aftermarket parts. In the case of my maf sensor, since the seller offered me a no hassle return, I took a chance and gave it a try. As I said, the sensor that I received was identical in every way to the oem part. And, two years later (and with only $89.00 invested) it's still performing perfectly. Is this an exception to the norm ? Perhaps, but my only objective was to share my experience with the rest of the forum. It's clear that there has been a mixture of positive and negative results with regard to other members using these knock-off sensors.

JD,
Sorry if my post caused miscommunication in any way. Like I said it seemed to work for some. My point was that it is one part of the system that could throw off the troubleshooting process which was in my case. Your advice here is always valued. :cheers:

No offense taken my friend. You know I love ya ! :)

Likewise! :)

Curious about the O2 sensor thing myself. On that link you posted, were those plug and play from that site? It's only the "Pre-Cat" that is usually needing replacement right?

I've had really bad hunting at idle (cold and warm), and have been chasing it for some time now (1128 and 1130 showing). New MAF recently. Checked for vacuum leaks as well, but never considered the O2 sensors. Could these be culprit for bad idling conditions?

It is extremely rare for 02 sensors in both banks to fail simultaneously "1128 and 1130"
Failed MAF or vacuum leaks cause about 90% of these codes. A failed O2 sensor is usually revealed by "aging O2 sensor" codes. (P2096)

2000 MAF replacement
 

Just replaced my MAF on the Boxster. The car was missing on acceleration and idling rough with RPM variable. I tried removing the MAF and cleaning with CRC MAFS cleaner. It said in the manual that it "may" help to do that. It did - about half way.
Checked with the local Porsche dealer. On sale the "Porsche" MAF was $565. They said to be careful about aftermarket parts.
I ordered the MAF from Pelican Parts. $235 and guess what the part that I bought was the same Bosch as the original down to the last number and symbols. Took the car for a run after install and it did very very well. Too bad about speed limits (not that we pay too much attention to them).
The Forum has helped me a lot over the last few years so here is my suggestions for an easier MAF change: 1. Buy the Torx 20 tool for the MAF removal. I found one for $8 for the complete set. You will only use it maybe twice so the expensive one is not necessary. 2. Buy a 1/4" socket knuckle to reach the outboard bolt with the Torx tool. Just makes it the easier. 3. This is important! Roll up a towel and place it under the MAF on both sides. That way when you drop the bolt it won't drop under the MAF GOD KNOWS WHERE and take you an extra hour the find the thing again :eek:
. Oh yeh - I forgot the trip to the auto parts for the angled mirror that I could not find in my shop.
Other than that it went really well. Needless to say if the MAF is bad you should replace the air filter at the same time.

Update. Stay away from the BuyAutoparts MAF. Mine lasted less than a year.

I started having driveability problems a couple of weeks ago that seemed to be getting worse., stumbling acceleration, occasional stall at idle and hunting idle, occasional check engine light.

I pulled the codes and got an ageing o2 sensor behind cat (a stored code I've had for ages now), large leak in EVAP system and a secondary air injection fault. The faults are intermittent, not constant, sometimes I will have them all then a couple of days later none, or maybe one or two.

I was just about to dig into the EVAP and secondary air injection system, something I did NOT want to do and I said to my self "Self? whats the last thing you did to the car?" And myself replied "I changed the MAF."

So I stopped talking to myself and changed out the BuyAutoparts MAF with the 12 year old Bosch that I had replaced (which still worked but was throwing codes) and the car drives perfectly now. No driveability problems whatsoever, in fact, the butt dyno tells me its pulling stronger and smoother.

So I learned my lesson, off to source a Bosch MAF.

I just got one from amazon for around $135, Bosch part, the 125.01 part. I got the last one from that seller and the next price up was around $160
It shows that the $130'ish one should be back in stock soon. Haven't installed it yet though..

It was it a Bosch box with a brown wax paper wrapping protecting the part.

Steve

Edit: Here is the one I got, except I got the $133 one that is sold by Amazon.com; it currently reports a 2-3 week shipping time:

http://www.amazon.com/gp/product/B001CO317M/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1

Beware. The genuine BOSCH part MAF you find at third party sellers haven't passed the tests that Porsche have in place for screening out bad sensors.

BOSCH sells them to private sellers for cheap, instead of putting them in the garbage. It's not that they don't work, they are just not meeting specs for a Porsche Car. Often called aftermarket MAFs e.g. eBay MAF sensor or those you find at 200~300 here and there.

The reason the P dealership's is $500+ is because it is a 'sensor' that actually been scrutinised and works as it should ;)

Go ask them!

Thats my understanding too. Hmmm. So my dilemma is to pay about $450 from Suncoast for a real one, or take a chance on a $130 Bosch. I googlated the Bosch part no., (not the Porsche part no.) and all the hits refer to porsche applications, so it seems they are only made for Porsche, so the ones out there for sale outside the dealership are all rejects.

Well, for the time being, the old one works, so at least I have some time to decide.