chrismon

At about 68kmi I replaced the MAF in my 2001 c320 with one from Germanstar.net. My orig part was throwing P0170s, etc., although it still ran fine. I put the new one in and no codes. Yay, right? Wrong. Throttle response was crap. When the car is shut off, and then restarted while still warm, it bogs and dies unless I give it 5-10 seconds at 3500RPM in neutral. It generally responds poorly to the throttle on anything but gentle throttle increases.

Today, I bought some of that new(ish) CRC MAF cleaner and cleaned the old MAF. I put the old MAF back in and the car was responding great again. Though I had no codes after 5 or so minutes of driving, I hooked up the reader and it said I had a P0170 pending. So, at least I know one thing, the old MAF isn't just dirty, it has gone bad. But it performs well.

I called up Germanstar and the person I spoke with said, "We sell hundreds of them... and... that's the strangest story I've ever heard." Perhaps I was foolish to start the conversation saying I wasn't expecting a refund or anything since it had been a few months...but I wasn't expecting a complete lack of sympathy, heh. At any rate. The part number is PBT-GF30, though it has none of the BOSCH emblems like the OEM part. Anyone else replace their MAF from Germanstar with this part # and had any troubles?

Could there be something else I am missing here? Something else gone wrong in combination that makes for good behavior with the old MAF and bad behavior with the new? Seems super odd to me. All I can think of is that I've got a bad MAF At this point I'm tempted to go to the dealer and buy the insert... if I can even get it without the whole collar

Yacht Master

China Knock off?

mleskovar

Many posts about failing new MAF. I don't understand the operation of it as well as some members here but it seems there's more to it in certain failure modes than just putting a new one in. Somebody jump in and correct my understanding if I'm wrong..... many sensors give input to the ECU to optimize engine output. Different parameters are changed - over time - as parts wear or conditions vary. So to make up for a MAF (or anything) going bad other conditions (timing/air/fuel/durations/etc.) are changed. When you put a new/good MAF in the ECU is expecting the old one and gives conditions for it that aren't good for the engine. Some posts say it takes X starts or X running time for the ECU to recalibrate the system and some say the ECU needs to be reset (via STAR) to start the 'learning' cycle over. When you put the old one back in it was happy again. Probably nothing wrong with the new MAF. If the engine all of a sudden starts crapping and throwing MAF related codes putting a new one in probably would fix it. Did I make sense?

chrismon

As far as the ECU re-learning, yes you made sense. I'm not unaware of this, and I had the new MAF in for at least 2 months. Within minutes of putting the old MAF in, as I said, throttle response is fine, and the CEL is back. The only thing I can think of is that I need to reset the ECU via a battery disconnect/drain. But I would think two months is good enough to provide the same learning effect?


I do not care where it comes from as long as it works properly. As far as what Germanstar says, they've had no problems with these. I'd love to hear about other peoples' experiences.

chrismon

Btw, sorry for the duplicate thread... I just realize I had started this conversation months ago here: https://mbworld.org/forums/c-class-w203/186385-2001-c320-warm-stalls-maf-replacement.html

I never did find a vacuum leak...

mleskovar

So much for that being a factor

xvvvz

So does your car run better when the GermanStar MAF is installed but you disconnect it? If so, that points to the MAF doesn't it?

I have read a number of posts in regard to GermanStar. At first, they seemed like they may be a good alternative. Over time, I have started to see more negative posts. I know I have read more than one post from people who got a bad MAF from GS. When they called to get a replacement, GermanStar said they had a very high failure rate with the sensors that were sold by themselves. GermanStar replaced it. Don't they come with a one year warranty? If it works better with the old one and better when the new one is installed but unplugged, then I think GS should send you another or allow you a credit on a brand new Bosch unit. Autohausaz.com also has good prices if you want a whole new unit.

Ausmbtech

As stated before, the ecu takes time to relearn the "long term" (stored) mixture adaptions. If with the new MAF/AMM you need to rev it for a bit in before it works ok then its probably using that to adjust the short term mixture adjustment so that it's drivable.

If the difference between the short term and long term mixture adjustments is quite large then the ECU recognises this as a fault and doesn't learn the new mixture adjustment when required too.

The fuel mixture needs to be reset for it to learn the new adjustment with the new MAF/AMM.