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Another AFM mystery...Can you help?


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So a little back story (without going into too many details): I purchased this car (1977 280z bone stock and sitting in a barn) extremely cheap ($900), everything was there and seemed to be in place; however, the previous owner said the car needed a new AFM. I purchased the car and AFM and installed it. The car ran, idled, etc.

 

While going through the entire car, I found that the engine bay wiring harness (fuel injector clips, other 2 prong clips, and wires looked like they had seen some sort of heat as they were all fringed and brittle. I was able to source a completely new harness from the ECU forward; however, it came out of a '78. Everything will match up except for the AFM connector. My '77 has 7 pins where the new harness from the '78 has only 5 pins. This is because Datsun changed from having the fuel cut-off controlled by the AFM to having it integrated to the oil pressure switch/sending unit (feel free to correct me if I'm wrong, but i'm fairly close with that statement, i think lol).

 

My question is this: Can I still use the '78 engine harness on my '77 and if so, how do i bypass or "jump" the fuel cut-off pins/switches within my '77 AFM? I have heard bits and pieces out there that this can be done but after hours of searching, was empty handed.

 

I'm extremely excited to get my hands dirty and get this Z on the road as it's my first 280z.

 

Any help will be greatly appreciated.

 

Thank you in advance.

 

-Adam

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You can probably just splice the 7 pin wiring into the 5 pin harness, and just not use the fuel cut off wires. Just need to find out which wires go the the air temp sensor in the afm and the position pin. 

 

How ever you will no longer have the fuel cut off. Your call, but I'd go with just finding a new ecu and afm.

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This option might be easier -  http://forums.hybridz.org/topic/104419-s30-and-s130-wiring-harness-repair-kits-you-need-this-if-you-have-an-l28e-or-l28et/?hl=harness   if you haven't torn things up yet.  It gets good reviews.

 

 

If I was in your boat and wanted to make the 78 harness work I would just open the Engine Fuel chapter of both FSMs and compare wires.  There are small detailed wring diagrams in each, easy to understand and specific to the EFI harness only.  Most wires will be the same, the ones that aren't might not matter.  The fuel pump cutoff might be run entirely by external relays attached to the alternator and oil pump switch. 

 

www.xenons30.com/reference

Edited by NewZed
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