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Discussion Starter · #1 ·
Well, just replaced my MAF for an OEM one from ECP and the problem is still present. I have no power at all. I fitted the new MAF and went for a drive and it is the same. So I stopped mid journey and unplugged it, then all power returned.

Will I have to 'run it in' as it were, or reset the error codes before it works? Since it is an OEM one, I shouldn't have to get it coded should I?
 

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A friend of mine experienced the same problem on his BMW made Rover Ray. Thought it was the MAF, replaced...still made no difference until he unplugged it. It turned out to be carbon/soot build up in the turbo intake. So he dismantled and cleaned that together with the EGR. His car sprang back to life.
 

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Just to be clear, are we discussing a genuine part or a fleabay special?

I have extensive experience in all things Maf, having had 4 in 1 year in my last car . . .
 

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Most ECUS recognise and learn a new component within 20 mins or so (maybe more, maybe less). I'm not familiar with this 'coding' thing that seems to be required on BMWS so that could indeed be your problem.
Of the 4 MAFS that I bought for my Alfa, one was a fake component mounted in a (cleaned up) Bosch housing [from mail order company], one was a terrible fake copy (from mail order company), the 3rd was a genuine Bosch component (from Alfa)that was intermittently faulty from day one and the 4th was fine (also from Alfa)

They are very tempramental peices of kit and you never know that yours is slightly duff until you fit one that is better and drive off with a smile on your face. Find out more about this coding thing - if it's not that, then consider sending the part back as defective.
 

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Discussion Starter · #6 ·
Well, I went back to the garage today and got the guy to erase the engine codes in the hope that this would finally fix my problem and make my MAF work. All codes erased and still no power.

This is really getting to me now. Surely it has to be the MAF sensor. When I unplug it, the car runs like a dream. As soon as it is plugged back in, it feels all bogged down and lacking.

Incase it throws any light onto it, the other codes that were present were:

MAF Sensor

Boost pressure too low

EGR flowrate (or something very similar)

and something to do with the air intake temp I think.

The guy said that all these are probably due to the MAF problem.

What do you guys think???
 

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well it seems to me that it cant be the maf as you have tried that, i would be more inclined to check out the egr valve / sensor as neil said earlier, you said the bmw codes came up as that as a fault and the symptoms are very similar to the maf fault
 

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Discussion Starter · #8 ·
I see what you are saying, but why when I unplug the MAF all works perfectly?
 

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When my Alfa's MAF was playing up, the OBD threw up 6 errors:

Boost pressure (overboost)
Boost pressure sensor
Intake air temperature sensor
EGR valve failure
Air flow sensor circuit failure (MAF)

and . . . .

Glowplugs ?????

In the end it was the MAF, the MAF and nothing but the MAF.

As you have rightly pointed out, logic would dictate that if you disconnect a faulty component and the car runs better - then that is the component at fault.

Don't rule out a dodgy EGR (in addition) but you could couldn't cure a stuck EGR by unplugging your MAF . . .

When your MAF in unplugged, the ECU runs on default settings which are based on engine speed, load etc etc to calculate the amount of fuel to inject. If this crude method works better than the actual MAF then I think that is clearly your problem.

There are ways that you can clean a MAF temporarily - which may improve the situation for a while - it'll cost you £3 and however long it takes to remove the MAF - don't bother if you intend to get a new one as a replacement/warranty claim etc.

Just ask if you're interested!

RP
 

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Discussion Starter · #10 ·
It's funny you should say that Ricepipe, as one of the other codes which I didn't think relevant was Glowplug Cylinder 3. Strange connection!!!

I did try cleaning my old MAF with IPA and it did seem to work for a week or so, then died completely. However, having just spent best part of £130 for a new MAF, I don't really want to try cleaning it. Do you think it is possible euro car parts supplied a duff one and if so, will they take it back? As there policy states 'no returns on electrical items'.
 

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It's funny you should say that Ricepipe, as one of the other codes which I didn't think relevant was Glowplug Cylinder 3. Strange connection!!!

I did try cleaning my old MAF with IPA and it did seem to work for a week or so, then died completely. However, having just spent best part of £130 for a new MAF, I don't really want to try cleaning it. Do you think it is possible euro car parts supplied a duff one and if so, will they take it back? As there policy states 'no returns on electrical items'.
No surprise really Ray - tha Alfa uses a BOSCH MAF and is a modern common rail diesel!

"No Returns" means when you order the wrong part - for example a 320i MAF for a 320d (hopefully you haven't done this)

BOSCH MAFs are very problematic from my experience. I'd offer the following advice.

1. Get BMW to confirm the Bosch part number (not the BMW part number - they will probably be different) and ensure you purchased the right product.

2. Somehow - if you can - find the same car as yours and swap the MAF over to provide concrete evidence that your part is faulty.

3. Even if you can't do (2) - Claim that you have done.

4. Send it back as faulty and get a replacement.

Like I said above, I had terrible trouble finding a fully functioning MAF and I purchased new from proper motor-factors. There are literally hundreds of convincing fake Bosch MAFS out there, and those that are real can easily be faulty. It's a nightmare!
 
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Discussion Starter · #12 ·
Luckily I still have the Bosch box that the MAF came in. I noticed a few numbers on the box. Will go and see if any of them match the old MAF that is in my boot. I should hope it is the correct one as I bought it from Euro Car Parts using the vin number as a reference.
 

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Discussion Starter · #13 · (Edited)
Just checked the part number on the box against the number on my old MAF housing. They are both the same numbers.

Is it fact, that I DO NOT need to have this new MAF sensor coded for it to work properly? Should it definately just work straight out of the box?

If this helps. First thing in the morning I can put my foot flat on the floor and there is absolutely nothing there. Takes an age to get to 20 - 30 mph. Yet when the engine has warmed up slightly, it seems to be a little better. Dont know if that will help anyone :confused:confused:confused
 

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Discussion Starter · #15 ·
Cheers Ronnie. I've just had a read through that. I have replaced my MAF with the exact same number 0 928 400 527 so I guess I do not need to get it coded.

Back to square one, lol
 

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Discussion Starter · #16 ·
Been to Euro's and they have replaced my MAF with another new one. Will fit this soon and hopefully that will cure the problem.

Had a chat to a tech at my local garage yesterday and he mentioned something about adaptation values. He said that after running for a while with a duff MAF, the ECU will automatically change its settings to cope. After fitting a new MAF he said the adaptation values may need to be reset. Has anyone heard of these values before and if so, do you think it could be the cause???
 

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Fingers crossed Ray.

Like I mentioned earlier, your ECU should adapt to a new component within a few minutes.
 

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Been to Euro's and they have replaced my MAF with another new one. Will fit this soon and hopefully that will cure the problem.

Had a chat to a tech at my local garage yesterday and he mentioned something about adaptation values. He said that after running for a while with a duff MAF, the ECU will automatically change its settings to cope. After fitting a new MAF he said the adaptation values may need to be reset. Has anyone heard of these values before and if so, do you think it could be the cause???
They will usually reset themselves, it is definitely worth doing though, you will need to find a good BMW specialist or main dealer to reset the adaptations as not all scanners/diagnostic equipment have the capabilities. :thumbsup
 

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Discussion Starter · #19 ·
Well, I've just fitted another new MAF. Although not running perfectly, I think I can notice a bit more power. I say think, because it has been that long since I it worked, I can't really remember how it should run :mad

However, it is still not as powerfull as it is when I unplug the MAF.

PS: Anyone live in the North London area who has 320d fancy taking mine for a spin and giving me their opinion on how it's running, because I seriously can't remember how it should be :confused
 
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