afm resistance

[taka21]

im attempting to test an afm that i recently bought and i cant find the ohm readings that im supposed to check it against
does anyone know this information
please help

 

[Bmettie]

here it is
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

 

[taka21]

thank you so much
i feel really silly for not being able to find it there

 

[TurboStreetCar]

You cant test the actual air metering device without a scope. It outputs a frequency. The Air temp sensor is what your testing with resistance.

 

[jetjock]

Yet another THA goose chase.

Fww there are resistance specs listed in the book for the Karman side of the AFM. You'd have to be desperate to use them though...

 

[TurboStreetCar]

Hmmm, i didnt know there were actually resistance specs for the frequency generator. In the TSRM? Or your tech books?

 

[jetjock]

My bad. I'm going by an 87 TSRM which is all I have. Page FI 78, Air Flow Meter (7MGTE).

Unsure about newer manuals but they aren't in the online one. Wouldn't be only thing Toyota deleted from later books. The detailed AC compressor rebuild for example. Anyway:

Ks > E1: infinity

E1 > Ks: 5-10k

Vc > E1: 10-15k

E1 > Vc: 5-10k

THA - E2: As stated in other manuals.

">" refers to the direction of current flow when using the meter. They're obviously checking device junctions. Think diode testing.

Edit: see post below...

 

[jetjock]

OK, I think I know why those specs aren't in newer manuals. They're wrong. In all my years of dickin' around with these cars I never resistance tested the Karman pins because it's just easier to dynamically test the AFM on the car or bench. So I decided to measure a known good one I still have lying around. I would use these values instead:

Resistance test:

Ks > E1: infinity

E1 > Ks: 4.1 meg

Vc > E1: 157k

E1 > Vc: 157k


Diode test:

Ks > E1: 2.490 volts

E1 > Ks: .700 volts

Vc > E1: 2.490 volts

E1 > Vc: .579 volts


Imo it's still much better to test it on the car...