AFM clarification - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z
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post #1 of 3 (permalink) Old 08-11-2019, 10:20 PM Thread Starter
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AFM clarification

My 78Z has been sitting for 10 years (in my shop). I seem to have forgotten most of what I think I knew. I'm in the process of cleaning connections under the hood after getting it started and moved outside so I can run the engine without killing myself with exhaust fumes.


Re the AFM: My understanding is that early meters have 2 more contacts for a total of 7. The extra 2 contacts are for the fuel pump and these meters are for 75 & 76 Zs. Later AFMs (ie 77 & 78) only have 5 contacts. Anyway, I'm going through the FSM and it references terminals 6, 7, 8, 9 & 27. Drawings in the FSM show resistance measurements being taken directly at the AFM terminals and not through the wiring harness.



Both 5 pin AFMs that I have have terminals 34, 35, 33, 32 & 25. If I'm reading the FSM right, then the AFMs that I have are all incorrect for this car. The car wiring harness has only 5 wires in the connector to the bottom of the AFM.


Is the FSM referring to the pins on the main connection to the ECU and not the meter itself? Where is the data for the pin out for the 5 terminal AFM?

Anyone can drive a new car.
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post #2 of 3 (permalink) Old 08-12-2019, 11:50 AM
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Yes, the FSM is refering either to pins in the ECU or numbered connections to relays and other components. Probably for "clarity" - to me it adds a little more confusion... They aren't using the numbering scheme of the relays so I don't expect necessarily to see the AFM numbering scheme being used either.

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post #3 of 3 (permalink) Old 08-12-2019, 03:03 PM Thread Starter
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Me thinks you're using the WAG method of estimating.


The car was built in 4/78 and the hard copy 78 FSM references pins that are not on the 5 pin AFP. The diagrams show a DVM connected for example to pin 27 and the body of the AFM.


A Youtube Ztherapy vid says that the 5 pin AFM was used on "later cars" and the two AFMs cannot be interchanged.


More digging shows a match in pin numbers (5-pin AFM) in the 82 and 84 digital copies of the FSM that I have. There was additional smog control etc that was added to the ZX.


Perhaps early 78 was a change over year and the later AFM was used.

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