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Altitude switch info


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Can anyone tell me where I can find info regarding the altitude switch in the California model 280z? Nissan shows it in section EC of the FSM but with no info. I found something in section EF with very little info. Iv'e gathered it is there to lower the amount of fuel injected to decrease wear of the emission components. But only by 6%, really? Does this really affect emissions that much? Does it really have that much of an effect on our cars equipped with it? Thanks

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I'd love some more information on the altitude switch. Specifically, I'd like to know if ALL ECM's from that era are wired (or programmed) to accept inputs from an altitude switch, or just select ones.

Why? I live at altitude but don't have the altitude switch in my 1980 ZX. I'd like to HARD WIRE the ECM to lean the mixture out, or put a toggle switch in, should I drive to lower altitude.

Such an input could be used for other purposes as well--- for example using negative logic, turning OFF enleanment during hard acceleration.

What do I need? Pin #'s, and someone with a compensator on their Z willing to take a few measurements, see if the switch opens or closes the circuit, etc.


Edited by Wade Nelson
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I don't remember where I found it, but I've got a chart that lists the part numbers for the ECU's from 75 through 83, and according to that chart, there was no distinction between California ECU's and the rest of the states until 1980.

By that, I mean... in 1980 and later years, the ECU used for California was different than the ECU used elsewhere, but prior to 80, that's not the case.

Note that it was not unusual for them to use different ECU's between auto and manual trans cars, and of course between turbo and non-turbo.

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