Help with some fault codes

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JeZ3
Joined: Sun 24 Jan, 2016 16:14
Posts: 15

  Z3 roadster 1.9
Location: Milton Keynes

Help with some fault codes

Post by JeZ3 » Sat 15 Jul, 2017 17:20

Hi

I wondering if I can get some help with some INPA fault codes I ran a diagnostic this morning got an 10, 62, 52 & 51

I believe 10 is a lamda issue can this be either pre or post cat, not sure on 51,52 ignition issue on cylinders is this likely to be coil failure related.

Thanks for your help

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2119

  Z3 roadster 1.9

Re: Help with some fault codes

Post by Del » Sat 15 Jul, 2017 17:59

If you have a 1997 1.9 it will be the M44 engine as mine is. The INPA codes vary slightly depending on the version of the ECU (DME) you have in the car. The M44 has Bosch DME M5.2.
Code 10 is a generic (unspecified) pre-cat lambda error code. The diagnostics on these pre-OBD II cars is not as sophisticated as some later BMWs in terms of pinpointing problems. The M44 only has one pre-cate lambda.

The other codes are 51 (cyl 2 misfire), code 52 (cyl 3 misfire) and 62 (misfire on various cyls). Typically these pop up when there is a problem elsewhere and they are not usually the primary fault.

From the above I do not know exactly what is wrong with the lambda. Sometimes the lambdas struggle to fine tune the mixture because something like a large air leak in the vacuum system is causing a combustion mixture which is so far wrong that the lambda cannot correct it - in which case it is the air leak that is the problem and not the sensor. I would first check the rubber MAF bellows as they commonly split. If all seems fine it may be a faulty sensor. The OE equivalent is Bosch (as per the DME) and the last time I checked they were about £70 from Car Parts for less

peter2b
Joined: Sat 01 Nov, 2014 18:47
Posts: 949

  Z3 roadster 2.2i
Location: cheshire

Re: Help with some fault codes

Post by peter2b » Sat 15 Jul, 2017 18:55

as Del said check the inlet hose after the maf sensor there are 2 small hoses mine had the same and found there was a split sorted (thanks Robert t)
peterz3

JeZ3
Joined: Sun 24 Jan, 2016 16:14
Posts: 15

  Z3 roadster 1.9
Location: Milton Keynes

Re: Help with some fault codes

Post by JeZ3 » Sun 16 Jul, 2017 19:04

Thanks for the replies, I've had the bellows off and there was no visible split. I can't see air getting in any where, sprayed some gas it to see if it reved higher. Smells like its running a bit rich so I think it may be the sensor.

Looks like I'll have to get the part ordered.

I'll update once I've got it done, I'm busy the next couple of weekends.

Thanks again

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colb
Joined: Sat 05 May, 2012 23:46
Posts: 576

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Help with some fault codes

Post by colb » Sun 16 Jul, 2017 23:01

If you are certain you have no air leaks in the rubber components after the Maf, it might be an idea to monitor the lambda sensor with the engine running to see what it is doing. A healthy sensor should be seen to have a rising and falling voltage at idle. A bad Maf will have an effect on what the exhaust sensor is detecting and the ecu will be adjusting the mixture to whatever the lambda is telling it. As Del says the codes you are seeing will not necessarily point you in the right direction for a bad component. Its very easy to start replacing everything if your not careful. My money would be on a bad Maf not necessarily the exhaust sensor. The misfires are probably caused by the misfueling that's going on due to a bad sensor which I suspect is the Maf. See if you can find a known good used one to try before shelling out on a new one, they are not cheap. Do not buy the cheap ebay ones, they either don't work or don't last long, only use Bosch or Siemens brands which were oem.
Colb
1999 BMW 1.8 Z3
1998 Honda Deauville NT650V

JeZ3
Joined: Sun 24 Jan, 2016 16:14
Posts: 15

  Z3 roadster 1.9
Location: Milton Keynes

Re: Help with some fault codes

Post by JeZ3 » Thu 10 Aug, 2017 19:02

Update

I managed to get a genuine MAF off EBAY bit of a risk as it was only £15.00 I thought I would take a risk, I'm happy to report this has solved the problem scanned again with no errors. Running some much better lets hope the sun comes out for the weekend.

Thanks for the advice

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colb
Joined: Sat 05 May, 2012 23:46
Posts: 576

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: Help with some fault codes

Post by colb » Thu 10 Aug, 2017 20:36

Good news you fixed it with a replacement Maf. Del was right about the usual cause being an air leak from split rubbers, when I had similar running problems you had I couldn't find any leaks and changed the exhaust sensors as mine seemed very slow to respond when monitored using diagnostic live data. Finally put it all right with a new Maf plug in and play you might say as the difference was immediately noticeable even though no codes had been set pointing to a faulty Maf and watching it on live data didn't reveal anything untoward as it was registering the airflow through it.
Colb
1999 BMW 1.8 Z3
1998 Honda Deauville NT650V

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