MAF cleaning M5

[shogun]

Just found this one. I think it is an M5. Maybe you dig a bit more on that page for more suitable repair tipes. A lot of pics on that page
http://www.louv.tv/cars/m5/MAF/

[uscharalph]

Just found this one. I think it is an M5. Maybe you dig a bit more on that page for more suitable repair tipes. A lot of pics on that page
http://www.louv.tv/cars/m5/MAF/
Nice link.

[ryan roopnarine]

jeez....a man with such a nice automobile but little knowledge of what he's doing or what's going on there.

i've cleaned my hot-wire MAF on my e34 and on my mother's car (ford) a bunch. first rule of doing that on a vehicle that you are not 100% sure of the wire strength/composition is to use a solvent that leaves no residue unless you want trouble. the only one that does that is contact cleaner marked "no residue." the fact that he's using simple green as the first step.....well. i hope that he never has trouble with that. the IP alcohol is a good step, but i don't think that it has the mechanical cleaning action to do well at that (i guess that's what the q-tip is for). I use contact cleaner because it has the cleaning action without scrubbing anything. ill spray my MAF on the e34 down and see it start to produce "grease" streaks and grease rainbows on the sides. i've only done one can of cleaner's worth, so i need to go back to the store and finish the job off.

[Bill R.]

hot film maf which is different from your hot wire maf due to the fact that the hot film maf only heats up to 167F above the ambient air temps when running and your hot wire heats up to 212F above ambient when running.. and your hot wire sensor has a burn off cycle that heats the wire up to 1000C or 1832F for one second after the engine is shut off to help keep your hot wire clean...but you still get stuff on it such as soot...The only thing i use on hot film or hot wire mass air flow sensors is throttle body spray cleaner, it leaves no residue and will dissolve dirt that the contact cleaner won't






jeez....a man with such a nice automobile but little knowledge of what he's doing or what's going on there.

i've cleaned my hot-wire MAF on my e34 and on my mother's car (ford) a bunch. first rule of doing that on a vehicle that you are not 100% sure of the wire strength/composition is to use a solvent that leaves no residue unless you want trouble. the only one that does that is contact cleaner marked "no residue." the fact that he's using simple green as the first step.....well. i hope that he never has trouble with that. the IP alcohol is a good step, but i don't think that it has the mechanical cleaning action to do well at that (i guess that's what the q-tip is for). I use contact cleaner because it has the cleaning action without scrubbing anything. ill spray my MAF on the e34 down and see it start to produce "grease" streaks and grease rainbows on the sides. i've only done one can of cleaner's worth, so i need to go back to the store and finish the job off.

[SRR2]

How do you determine that cleaning a MAF is necessary? Wait for an error to be thrown, some particular performance problem, routine maintenance, or something else?

[shogun]

Actually it should clean itself:

When the air-mass sensor is working normal, the hot wire does not glow. To burn off any deposits and dirt, the control system will heat the wire red hot to 1000 degrees Celsius (1800 F) for about 1 second, after you shut off your engine. This is the cleaning process and only performed if the engine is revved up to at least 2000 rpm. So starting your engine, let it idle for a certain time and shut off means no hot wire cleaning.


http://shrubbery.student.utwente.nl/sean750/MAF_v12/MAFtroubleshooting.htm

[Bill R.]

slight hesitation or flat spot and sometimes a lean code. I see it a lot on
fords and gm products.. and it still shows up on even the self cleaning ones.
The ford thin films are the worst, you can remove the sensor on them and look at it and see the layer of dirt on the side of the sensor that the air hits first and it will be clean and shiny on the back side...When it gets a layer of dirt like this it acts as an insulator and since its insulated the air passing over it doesn't make much change in the temp so the computer reads this as a smaller throttle opening and injects less fuel, but in reality your moving more air so it becomes lean, Ford rangers do this all the time and you get a pinging issue with them under light throttle from this.






How do you determine that cleaning a MAF is necessary? Wait for an error to be thrown, some particular performance problem, routine maintenance, or something else?

[Bill R.]

have buildup on them that can be helped by cleaning.




Actually it should clean itself:

When the air-mass sensor is working normal, the hot wire does not glow. To burn off any deposits and dirt, the control system will heat the wire red hot to 1000 degrees Celsius (1800 F) for about 1 second, after you shut off your engine. This is the cleaning process and only performed if the engine is revved up to at least 2000 rpm. So starting your engine, let it idle for a certain time and shut off means no hot wire cleaning.


http://shrubbery.student.utwente.nl/sean750/MAF_v12/MAFtroubleshooting.htm

[Anthony (M5 in Calgary)]

hot film maf which is different from your hot wire maf due to the fact that the hot film maf only heats up to 167F above the ambient air temps when running and your hot wire heats up to 212F above ambient when running.. and your hot wire sensor has a burn off cycle that heats the wire up to 1000C or 1832F for one second after the engine is shut off to help keep your hot wire clean...but you still get stuff on it such as soot...The only thing i use on hot film or hot wire mass air flow sensors is throttle body spray cleaner, it leaves no residue and will dissolve dirt that the contact cleaner won't

This summer I proved that a part throttle/moderate RPM & load ping problem on my '91 M5 (11'90 build) was cured with a MAF swap from a club member's car. The car runs fine, gets similar fuel economy and power otherwise and doesn't throw any codes. The ping gets worse as ambient temperatures rise.

Before I fork over big $$ for a new or re-built MAF I'd like to understand the failure mode here. Comments?

My options for MAF replacement:

1) used, ~U$250 if I could find one
2) re-furb from BMA by Python U$399 (who is Python, reputation?)
3) re-furb from BMA by Bosch U$799
4) new OEM U$ God only knows

I've been advised not to try cleaning the hot wire as it is exremely fragile.