M3Jokster
09-23-2002, 03:51 PM
I need help guys,
I just bought a used 540i HFM...and would like to test it out to see if it's in working order. what i need from u guys, are the resistance numbers on the HFM.
I was told that there should be a risistance between the the 4 lead wires.
TIA
m3jokster.
Dark Helmet
09-23-2002, 04:40 PM
i have NO idea.... sorry.
abakos
09-24-2002, 07:46 AM
I have all kinds of E34 material...need more info.
BTW-- pardon my ignorance, but what does HFM stand for?
JamesM3M5
09-24-2002, 08:21 AM
Hot Film (air mass) Meter. It uses a film of metal in the airflow path to measure the mass of air passing over it. An HWM uses a wire instead of a film.
That's all I know about that. As far as testing? Sorry, can't help, either.
abakos
09-24-2002, 11:25 AM
Gotchya-- MAF Sensor/Counterpart :)
Thanks James.
And I don't have a clue what to check on that thing. Can't you compare it to another one or hook it up and see what happens?
I'll see what I can find later on when I get home--
M3Jokster
09-24-2002, 04:18 PM
that's what i was told......bring it to a dealer and ask them to install on a 540i if they have one....and hope that it works!
I was told that it either works or don't work.
Atticka
09-25-2002, 12:21 AM
I've got a bentley for 5 series, years 82-88 (E28)
what year is the part from, I'll see if I can find it for you.....
JamesM3M5
09-25-2002, 08:11 AM
The E28 has no such part, so the Bentley doesn't help. The E28 uses a vane air-flow meter--a spring-loaded flap in the air path--to measure the air coming in. The HFM or HWM is much less restrictive.
For you E28 guys, see:
http://www.splitsec.com and http://www.teamdfl.com/bmw/e28/induction/maf.html
Easy 20+HP gain and torque all through the rev range.
Sorry, I STILL don't know how to test the thing, though. You need a flow-bench to get air going through and the pin-out to power the sucker. They require DC voltage to get the film hot and then something to interpret the signal.
abakos
09-25-2002, 09:59 AM
Atticka-- My Bently for E34 acknowledges the presence of the part for 2 model years, but doesn't tell me how to run a diagnostic.
James is right-- That thing has to be a bear to test outside the vehicle. Even if you could run some sort of test without air flow, it's possible that it may not function correctly in the car.
As they say...the proof is in the pudding. It sounds like your best bet is to just put it on a car.
Sorry I couldn't find anything else--:dunno