I have been sorting some ABS and SRS faults on my Z3. While looking at the scanner, code 8 came up for the MAF sensor even though the car seems to be running fine. I thought I may as well replace it. I bought a cheap one from eBay just to see what it was like. This was a big mistake because while fitted, the engine is rough during idle and although code 8 has gone, 170 and 173 have appeared! I'm putting the old MAF sensor back in for now. Maybe I'm behind the times with discovering this but thought it would be worth warning people. A new MAF sensor from BMW direct is 300 quid so that isn't happening either.
Cheap mass airflow sensors!
- Thread starter NickUK
- Start date
Lesson learned, thanks for sharing your experience! 
You can run without the MAF plugged in for diagnostics. Clear all the codes and run it unplugged. As for the cheap parts, you can sometimes find legit parts comparatively cheap. Managed to find a genuine Hella MAF for my Z4 for about £90 and was sceptical it was going to be a pattern one with no markings on it (frustratingly for me it wasn't actually my problem!)
I won't tell you how cheap the MAF I bought was.
Without looking at the diagnostics, the car runs best with the old MAF, second best with it unplugged (but still sounds alright) and dog rough with the new, cheap as chips MAF. My slight concern was that there was another issue with those separate codes (170 and 173) but they don't come up when the old MAF is plugged in or nothing at all is connected. It's amazing how a 'new' part can make things worse regardless of how cheap it is.
- Joined
- Nov 25, 2012
- Points
- 178
- Location
- Newport, South Wales,UK
- Model of Z
- Z3 M43 1.8 (1999) and Z4 E85 2.0i (2007)
Lesson learnt like a good many of us over the years, cheap ebay sourced pattern parts rarely work or work for long this applies not only to the Maf, camshaft sensors and crankshaft sensors should be added to the list of pattern parts to be avoided. You can't go wrong with puka BMW spares but your wallet will always take a hit. I always try and use Bosch or Siemens oem brands, I have had good results using HAAS camshaft sensors. Well known brands like Hella are also worthy of consideration. Same for replacing Exhaust sensors go Oem.
As to your Maf setting a code they are known for not setting a code in some cases, I had this with a bad Maf, sent me off chasing other sensors before I took the plunge and fitted a new Bosch Maf. Cure was instant when fitted, car transformed. Might be worth getting your car plugged in and viewing the live data from the Maf just to see what it is doing if anything. The flow of air through it is measured and compared with what the exhaust sensors are seeing passing by them. If the Maf is under reading or over reading the ECU will be adjusting your fuel trims as in most cases it thinks the engine is running lean, tells the injectors to put more fuel in to richen the mixture it will do this until it reaches about 20% more fuel then gives up and as a sulk it lights the EML on your dash as well as setting codes for fuel trims. An episode like this is usually down to leaks in the vaccum system after the Maf and before the exhaust sensors so worth checking for any split rubber hoses and intake bellows across the whole engine. I did try spraying Maf cleaner on my duff one but all that did was kill it completly so not a fan of cleaning them.
As to your Maf setting a code they are known for not setting a code in some cases, I had this with a bad Maf, sent me off chasing other sensors before I took the plunge and fitted a new Bosch Maf. Cure was instant when fitted, car transformed. Might be worth getting your car plugged in and viewing the live data from the Maf just to see what it is doing if anything. The flow of air through it is measured and compared with what the exhaust sensors are seeing passing by them. If the Maf is under reading or over reading the ECU will be adjusting your fuel trims as in most cases it thinks the engine is running lean, tells the injectors to put more fuel in to richen the mixture it will do this until it reaches about 20% more fuel then gives up and as a sulk it lights the EML on your dash as well as setting codes for fuel trims. An episode like this is usually down to leaks in the vaccum system after the Maf and before the exhaust sensors so worth checking for any split rubber hoses and intake bellows across the whole engine. I did try spraying Maf cleaner on my duff one but all that did was kill it completly so not a fan of cleaning them.
It's definitely a case of buy cheap, buy twice. I usually learn the hard way but will be getting a refund on that part.
I bought my Z3 as a low cost project and done alright with that so far replacing a handbrake cable, blower resistor, seat kebabs and a few other bits. I'm also repairing some nasty bodywork damage myself. I appreciate a few costs for proper parts will pop up though if I want to keep it on the road!
I have an Autel ML629 because it's the cheapest one I know of that can also deal with SRS / airbag codes and ABS along with the usual OBDII. It needs a 20 pin adaptor to plug into my Z3 but they all need that.
Non BMW handbrake cables are a false economy I feel. BMW are barely any more expensive - £20/£22 I think. And don’t need fettling to make flats to go through the holes in handbrake lever.
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I dunno, there is no performance for the handbrake, just needs setting up correctly. It's a cable. I paid £7: summat
It's just a cable pulling some old school shoes onto the inside of some modern discs innit?
These guys are good. £4 on the whole order and they'll pick up for free, n questions, anything you change your mind about. 7 days max
www.onlinecarparts.co.uk
Wait for fri sat sun to order, and it goes to 28% at least most weekends.
It's just a cable pulling some old school shoes onto the inside of some modern discs innit?
These guys are good. £4 on the whole order and they'll pick up for free, n questions, anything you change your mind about. 7 days max
Cable, parking brake A.B.S. K19995 for left-/right-hand traffic buy cheap online
A.B.S. K19995 Cable, parking brake for left-/right-hand traffic for MERCEDES-BENZ, FORD, BMW, VW, AUDI - a wide range and high quality Cable, parking brake spare parts online.
Wait for fri sat sun to order, and it goes to 28% at least most weekends.
Nope but I’d rather trust BMW to produce something that won’t crack the outer sheath and seize up. But at £7 if the flats are pre machined that’s a lot cheaper than the £18 ish I’ve paid for aftermarket before.I dunno, there is no performance for the handbrake, just needs setting up correctly. It's a cable. I paid £7: summat
It's just a cable pulling some old school shoes onto the inside of some modern discs innit?
These guys are good. £4 on the whole order and they'll pick up for free, n questions, anything you change your mind about. 7 days max
Cable, parking brake A.B.S. K19995 for left-/right-hand traffic buy cheap online
A.B.S. K19995 Cable, parking brake for left-/right-hand traffic for MERCEDES-BENZ, FORD, BMW, VW, AUDI - a wide range and high quality Cable, parking brake spare parts online.
Wait for fri sat sun to order, and it goes to 28% at least most weekends.
Rest assured my handbrake cable came from a BMW dealership
I just ordered a new water pipe from a dealership too because it's only 4 quid more than buying it online from Lithuania!
Most of my cost-cutting is through doing the labour myself. I remember you or somebody else advising to buy a BMW handbrake cable back when I fitted it so the advice does sink in. Thanks.