I had heard that the sweep style of the later AFM's was different than the earlier ones... Something like the ZX's used a logarithmic sweep for the voltage while the earlier Z's used a linear output?

I have no input as to the validity of that, but I think I read it on the internets.

Seems reasonable.  The ZX's used a different ECU also.

I wonder if the circuit boards inside might be the same.  Something we can compare without too much trouble.  Probably have numbers.

Here's a start.  An A31 060 001 from a 1975 280Z, I think.  Kind of looks like a Bosch part number on the board, but it says OHMIC.  1 288 310 011 with a big 7444 beside it.

 

13 hours ago, Zed Head said:

board, says OHMIC.  1 288 310 011 with a big 7444 beside it.

I suspect OHMIC is a company that Bosch sub-contracted out to for construction of the board. I bet that Bosch did not silk screened their own boards.

And the 7444 is probably a date code for 44th week of 74 (making it a prime candidate for the 75 model year).

It's a bosch unit. That is a Bosch symbol next to the "+" symbol. I think OHMIC desrcibes the type of contact used to measure resistence and therefore vane position.

"Generally the term "ohmic contact" implicitly refers to an ohmic contact of a metal to a semiconductor, where achieving ohmic behaviour is possible but requires careful technique"

https://en.m.wikipedia.org/wiki/Ohmic_contact

The AFM cover was the typical green Nissan label.  If later AFM's use the same board the odds are good, I think, that the "tuning" is the same.  Anybody got a 1978 handy?  I think I sent mine to @rcb280z

I have an MSA AFM on my car now.  MSA says that Fuel Injection Corp. uses a thicker material on the conductive pattern to make it more durable.

Zed Head, the one I got from you has the 7 pins and fuel pump cut off so I assume its a 77.

Chiefmd, I think "if" you need to do anything to the refurbished unit, after installing on your 77, it will just be an adjustment on the "idle air screw" at the bottom of the AFM.

This is assuming it hasn't been opened and molested. 

1 hour ago, rcb280z said:

Zed Head, the one I got from you has the 7 pins and fuel pump cut off so I assume its a 77.

It's a 78, pretty sure, I got it from a 1978 parts car that seemed all original.  The fuel pump pins are "useless" as I showed above, post #8, with the Nissan wiring diagram.  Nissan probably had old AFM's in stock when they made the model switch.

If you can get the part number from the board that would be cool.  No picture necessary, although pictures do add something.

It has the fuel pump cut off inside. It worked on my 77 when I tested it otherwise I would not have used it.

Here's a pic of the board.

 

 

Edited December 29, 20186 yr by rcb280z

Thanks,  looks like it has the Nissan A31 number, along with an extra number.  No simple Bosch number comparisons.  Dang.

Here's a pic of the AFM in my 77. I haven't owned the car since new so I can't guarantee that it's original, but I believe it is:

Seems the later AFM's used the green protective screen printed coating over the laser trimmed resistors.