Hi all -
I just picked up an '85 720 the other day, and I'm tackling an issue with the carburetor...specifically, the electrical components that "should" be connected on the carburetor via the large 6-pin electrical connector. I've looked at a variety of threads on these carbs and I've not been successful correctly identifying each of the components. Various people, manuals, and Nissan OEM language, all see to call these devices something different. I'm hoping to get some clarification.
The carburetor I have on the truck is NOT the OEM Nissan carb. It appears to be a new eBay $85 special, installed by the previous owner, in attempt to get the engine to pass emissions. This carb is missing a few of the electrical devices the OEM carb had, so I expect I may need to replace this unit with another, in order to pass emissions.
I found a wiring diagram for a Z24 engine, but I'm not sure of the year it was for. It identifies four devices, that are likely connected to the carburetor, but I'm not sure what is what. I'll post that image below, if I can figure out how to host it.
The items identified in the wiring diagram are:
1. Auto Choke Heater. (1) wire. Blue (L).
2. Air-Fuel Ratio Solenoid. (2) wires. Yellow with black stripe (YB) and White (W).
3. Throttle Valve Switch. (1) wire. Green with white stripe (GW).
4. Anti-Dieseling Solenoid. (2) wires. Red (R) and Black (B).
First, there is (supposed to be) a two wire electrical device on the front of the carburetor, above the float bowl. What is that device called? It appears this might be the device with the Yellow-Black and White wires, but I can't confirm. If so, it must be the Air-Fuel Ratio solenoid. Is this commonly called something else?
Second, the device that is visible from the passenger side of the carburetor (technically screwed into the carb from the back-side though), appears to have a Red and black wire. Is this the Anti-Dieseling Solenoid? If so, is that referred to as the IACV-FICD solenoid? I looked up an FICD solenoid, and that refers to a device that causes the idle to rise when the A/C system is activated. I don't have A/C, so what is this device? Are the IACV and FICD different devices? Are the combined on some models? If not, where would I locate a separate FICD device on A/C equipped models?
Third, there is a single blue wire attached to what appears to be an electric choke on the back-side of the carb, at the top. Is there a difference between a auto-choke and an auto-choke "heater"?
Last, there is a Gree-White wire on the connector, but nowhere to connect it. I looked at some other pics of the hitachi carb and it appears there is a small device on the back of the carb, nearer the driver-side. Is there a throttle valve switch that is supposed to be there? Is that commonly called something else?
I'm wondering if I can purchase an affordable carburetor (not a $475 unit) that has all the required connections, or if it's reasonable to expect I could get this engine to pass emissions with a more basic carburetor, like the new unit that was installed.
I am also still having trouble correctly identifying some of the various vacuum components on the engine, and ensuring the vacuum lines are correct. I'll post a new topic for that though.
Thanks for any help that can be offered!
http://nissannut.com/projects/z24i_fuel ... wiring.jpg
Images of the carb I have on now
https://www.ebay.com/itm/Carburetor-For ... .l4275.c10