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Discussion Starter #1
Hi,

Bosch no longer make new MAF sensors for the 164 so can I ask what other owners are doing when theirs get tired/die?
 

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I've found numerous good used ones on Ebay or from my local Alfa guy. Never had an issue finding one.
 

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the MAF can actually be 'refurbed' pretty easily without changing the calibration. If youi take the cover off, you will see a wiper arm and a carbon track it follows. The carbon track can get worn in spots -- if you carefully mark the arm/pivot position, loosen the arm allen holding setscrewm and simply push the arm down a tiny bit, (without changing the rotational relationship to the air flap) you will find it moves the contact a bit outward-- toward fresh virgin carbon. 1mm is enough.

At least I;ve done that twice on 24V AFM and it worked great.
 

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I know I am resurrecting a very old post, but my MAF needs replacement. My mechanic had to set it too lean to get it to work. I get a gas smell when it is idling and the check engine light comes on. The light goes away when I start driving. Has anyone had any luck with replacement MAF's? He has told me that he has done just about all he can with the current one.

Let me know and thanks.

Jeff
Dallas

1994 LS
 

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Jeff you have a Air Flow Meter (AFM) not MAF on your 164. Mass Air Flow sensor is used on 164 Q4 and on many other newer cars and trucks.

There is one on AU ebay now for Alfa Romeo 164 V6 3.0 24 valve Bosch 0 280 203 026 air flow meter AFM.


Check your part nmber on your 164LS If it is a 026 looks like Porche 944 uses same AFM.


Here is repair service in Boca Rotan FL listed on ebay:
https://www.ebay.com/itm/0280203026-Porsche-Air-Mass-Meter-Porsche-944-Turbo-951-Bosch-Mass-Air-Flow/272268128400?_trkparms=aid=222007&algo=SIM.MBE&ao=1&asc=20131003132420&meid=398d36c20dff49aab914ec1850824e1b&pid=100005&rk=1&rkt=2&sd=362546374625&itm=272268128400&_trksid=p2047675.c100005.m1851#viTabs_0
 

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Discussion Starter #7
the MAF can actually be 'refurbed' pretty easily without changing the calibration. If youi take the cover off, you will see a wiper arm and a carbon track it follows. The carbon track can get worn in spots -- if you carefully mark the arm/pivot position, loosen the arm allen holding setscrewm and simply push the arm down a tiny bit, (without changing the rotational relationship to the air flap) you will find it moves the contact a bit outward-- toward fresh virgin carbon. 1mm is enough.

At least I;ve done that twice on 24V AFM and it worked great.
Brilliant idea, Goats!
I have now obtained an ex-Porsche AFM so have spare while refurbing. Previously abandoned a refurb attempt on original, where I planned to move the PCB, as the screws were in so tight I thought they would shear off. Slightly squishing the arm to move the contacts out a fraction sounds way more practical. Thank you.
 

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Richard, is the air flow meter the same as the one in the Porsche 944? I was trying to figure out some way of confirmation on that. If they are the same, I will have mine sent off to be rebuilt. Let me know and thanks.

Jeff
 

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Discussion Starter #9
Richard, is the air flow meter the same as the one in the Porsche 944? I was trying to figure out some way of confirmation on that. If they are the same, I will have mine sent off to be rebuilt. Let me know and thanks.

Jeff
Hi, Jeff.

If the Bosch part number for your AFM and that of the Porsche are the same then, as far as I understand it, the units are identical. Certainly the Porsche unit I bought looks identical to that on my 164. On holiday at the moment so don't have the part numbers to hand but if you check them on the AFM on your car and if you find the same for a Porsche unit then that is your answer. As far as I understand it, there is no difference between buying, for example, a Bosch temp sensor that also fits another vehicle as long as the Bosch part number for the one that fits your 164 matches that of the Bosch part number for the other. If there is good weather next week I'll be looking to fit the one I bought then and can let you know how it runs, if that helps.
 

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Hi Richard and thanks for the reply back. I spoke with my mechanic and he told me where to find the part number on my AMF. I will take care of that this weekend. Please let me know how the rebuilt part performs. If it performs well, I will have mine rebuilt. Otherwise I will be purchasing the used one from Australia on Ebay.

Enjoy your holiday and safe travels home.

Cheers,

Jeff
Dallas, TX
 

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Hi Richard and thanks for the reply back. I spoke with my mechanic and he told me where to find the part number on my AMF. I will take care of that this weekend. Please let me know how the rebuilt part performs. If it performs well, I will have mine rebuilt. Otherwise I will be purchasing the used one from Australia on Ebay.

Enjoy your holiday and safe travels home.

Cheers,

Jeff
Dallas, TX
If it is the same Bosch number as the ones listed for 944 Porsche you should be able to find one closer to home.
 

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Discussion Starter #12
If it is the same Bosch number as the ones listed for 944 Porsche you should be able to find one closer to home.
Hi,
Back from holidays now and have the AFM on my to do list.
As for location availability, I am based in the UK and bought mine from the US. Some people are asking crazy money for these and this US seller offered the best price/delivery/seller choice - especially as planning to refurb the item anyway.
In theory, seeing as it is a European part and am in Europe, it would make sense to buy it from Europe - in reality not always the case.
Such is life...
 

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Discussion Starter #13
Hi Richard and thanks for the reply back. I spoke with my mechanic and he told me where to find the part number on my AMF. I will take care of that this weekend. Please let me know how the rebuilt part performs. If it performs well, I will have mine rebuilt. Otherwise I will be purchasing the used one from Australia on Ebay.

Enjoy your holiday and safe travels home.

Cheers,

Jeff
Dallas, TX
Hi Jeff, if the person you are planning to rebuild yours is competent and reliable and yours hasn't been rebuilt before, from what Goats has described there shouldn't be any issues. I just prefer to have a spare unit in case something does go wrong. Given the huge fluctuation in prices of these AFM units I chose to put off the refurb process until was able to obtain a replacement for a good price - which I have now done.
Suggest you don't wait for me to refurb mine as, although it is on my to do list, so are 1,000 other things and you could be waiting several months. If you plan to keep you car, maybe keep a look out for a good priced replacement as a spare (test it when it arrives), in case the refurb plans fail.
Just my view.
All the best with it and will post what happens at this end when do get round to it.
Richard
 

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I have not yet made my purchase but need to make a decision soon. I found a new Bosch unit from a Porsche part supplier in Atlanta (same part number) and it is slightly over $600. My question is can these units be swapped out "as-is" or are there any settings or calibrations done so that they are not interchangeable? Otherwise I will need to try and find a good used, Alfa one.

Let me know if anyone has any thoughts.

Thanks.
 

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A word of warning re: Alfa / Bosch AFM. Each AFM, as it comes out of the factory, is laser trimmed for resistance vs opening angle. This is a pretty precise permanent adjustment to the circuit board trimmer resistors -- The test fixture blows a precise air rate through the opening, and the laser actually adjusts (removes) electrical resistance through the trimmers in a multi-point calibration process. What does this mean in practice? It means that the arm to flapper angular position must be maintained (and therefore the arm/trace relationship as well) as well as the spring force on the flapper must not be disturbed. It also means one can;t swap out flapper springs/circuit boards etc.
The whole thing is dicey. Would have been WAY better to simply put a MAF in that uses heat conductivity. Then everything else (mechanical stuff) becomes somewhat moot.
 

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A word of warning re: Alfa / Bosch AFM. Each AFM, as it comes out of the factory, is laser trimmed for resistance vs opening angle. This is a pretty precise permanent adjustment to the circuit board trimmer resistors -- The test fixture blows a precise air rate through the opening, and the laser actually adjusts (removes) electrical resistance through the trimmers in a multi-point calibration process. What does this mean in practice? It means that the arm to flapper angular position must be maintained (and therefore the arm/trace relationship as well) as well as the spring force on the flapper must not be disturbed. It also means one can;t swap out flapper springs/circuit boards etc.
The whole thing is dicey. Would have been WAY better to simply put a MAF in that uses heat conductivity. Then everything else (mechanical stuff) becomes somewhat moot.
Yup. I would not adjust or mess withe these, ever. Just asking for trouble. Cleaning it is another story and fairly simple.
 

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So can I swap out mine with a new one with the same Bosch part number but for a Porsche? The used on Ebay from here in the US looks like it has been opened and messed with.
 

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I would think so, but have never tried this. When Bosch made them, I doubt there was different calibration curves for Porsche vs Alfa.
 

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Thanks Goats. That was my thought as well. My thinking is that the fuel injection management system should work with the data the sensors are providing and it will instruct the air flow meter on how to operate. That may be an oversimplification of how things work but seems reasonable. I will discuss this with my mechanic and let everyone know how we proceed and what the results are.
 

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well its kind of like that but not really. The AFM is delivered a fixed, regulated voltage as an input, and it outputs a variable voltage that is proportional to the air flow RATE (volume of air/unit of time). The rate is measured by the degrees of 'opening' of the flap, which in turn wipes the contact, which in turn varies the voltage delivered as an output. So the AFM is an INPUT to the fuel injection system which tells the computer how much air is being sucked into the cylinders, and therefore how much fuel needs to be injected to keep the mixture within reasonable stochiometrics.

If you can imagine an AFM that is 'out of trim' (ie not calibrated) it might tell the computer that at idle, the air going into the manifold (and thus the cylinders) is x. But the true air rate is x-y. Thus, the computer will compensate fuel to the x value, but since the true rate is x-y, it will be rich. The O2 sensor will then measure this, and if its too far out , will flash the CEL for 'sensor out of range' code.

Anywho give it a shake lets see what happens. How much $ is this porsche AFM ? Can you return it if its a no-go (which I dont think is likely at all)
 
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