Hella MAF - Warning (I think)

[Ruofdez]

When I bought my car the MAF was dead producing no reading so replaced it with a Hella MAF.

This MAF started causing problems a few months in. Acceleration had become jerky, like I was going on and off the power slightly at 3-4k revs, only fairly subtle but very irritating and if the pedal was held there it would almost kangaroo and it forced me to change my driving style. Stopped doing it once MAF unplugged. The eBay seller I bought it from was brilliant and gave me another no questions asked however 2 months later with the second one the same issue has returned. Once again if the MAF is unplugged it doesn't have this problem.

Is there any possible explanation besides the Hella MAF not being up to the job? Seems a real coincidence that both are causing the same problem after the same amount of time. Just wanted to check with you experts before I go back to the seller and try and get another replacement, hopefully another brand or pay the extra for the genuine.

Thank you.

--Update--
Turns out the MAF was not at fault so don't be put off by Hella. Sorry for the incorrect assumption.

[enuff_zed]

You don't have a K&N or other oiled filter do you?
Heard anecdotal stories of these getting muck on the MAF and causing issues.

[AndyBeech]

I would always go Genuine or at least OEM with air sensors, pretty crucial part in the intake chain and not worth risking problems with cheaper parts.
Pretty sure VDO is the OEM for that part, £170 or so new, not that much of an outlay in the scheme of things and should be the same part BMW would give you minus a BMW stamp on the part (and the cost).

I would recommend getting codes read if you can, might be a bit more accurate as to what the problem is if any are recorded as not necessarily the MAF. Unplugging it makes your car run a different map and doesn't always mean it's the problem, though in this case does sound like it is.

[mmm-five]

Strange that it drives fine without a MAF at all though?

You sure the previous owner hasn't mapped the MAF out?

[Ruofdez]

You don't have a K&N or other oiled filter do you?
Heard anecdotal stories of these getting muck on the MAF and causing issues.

I had heard the same and though it seemed unlikely to be the cause, to be safe after the first one went back I replaced the K&N filter with a standard filter so doesn't look like that was to blame. Thanks for the suggestion though.

I would always go Genuine or at least OEM with air sensors, pretty crucial part in the intake chain and not worth risking problems with cheaper parts.
Pretty sure VDO is the OEM for that part, £170 or so new, not that much of an outlay in the scheme of things and should be the same part BMW would give you minus a BMW stamp on the part (and the cost).

I would recommend getting codes read if you can, might be a bit more accurate as to what the problem is if any are recorded as not necessarily the MAF. Unplugging it makes your car run a different map and doesn't always mean it's the problem, though in this case does sound like it is.

I can see your point now! I thought by going for a decent brand in Hella that it would be ok but it would seem not and in future I'll go for genuine ones. I have a code reader so will confirm there's nothing else going on.

Strange that it drives fine without a MAF at all though?

You sure the previous owner hasn't mapped the MAF out?

Well it doesn't run perfectly without the MAF. Above 5,000 revs it doesn't have quite the same power/noise, presumably as it has to assume a worst case in terms of air intake and when pushing the brake pedal the revs rise, however the rest of the time when driving there's very little noticeable difference.

[g3org3y]

I fitted a Hella MAF to my M54 engined 330Ci. Not had any issues with it tbh.

[Ruofdez]

I fitted a Hella MAF to my M54 engined 330Ci. Not had any issues with it tbh.

I don’t think that’s quite the same one. I made the mistake of buying a genuine one from a 330 as I thought it would be the same and turned out it was a little smaller so had to send it back. I think the one for the Z4 is only shared with the 2004-2006 7 series and X5. However regardless it shows that they’re not all bad!

[g3org3y]

I fitted a Hella MAF to my M54 engined 330Ci. Not had any issues with it tbh.

I don’t think that’s quite the same one. I made the mistake of buying a genuine one from a 330 as I thought it would be the same and turned out it was a little smaller so had to send it back. I think the one for the Z4 is only shared with the 2004-2006 7 series and X5. However regardless it shows that they’re not all bad!

You are right though about the MAFs. RealOEM part number for the 330 M54 is 13627567451, for the Z4 M54 it's 13627566983

[Portlandit]

Hello Ruofdez,
I have the same problem as you:
“ Acceleration had become jerky, like I was going on and off the power slightly at 3-4k revs, only fairly subtle but very irritating and if the pedal was held there it would almost kangaroo and it forced me to change my driving style.”

Can you tell me how you solved the problem.

Sorry, my english is not very good

[Ranger527]

What ended up causing your jerky throttle response ?

[Ruofdez]

I’m afraid I never found out the cause. I have a different z4 now. I didn’t get rid because of that, but I’ve not had it on the two z4s I’ve had since. Not sure if it’s a potential issue prefacelift. Saying that I didn’t really find anyone else having the same issue. Have you got the same?