[Roadsters] 1970 Schematic

[Gary and Cindy Ault]

The valve on the line to the intake manifold was called an "anti-backfire" 
valve.  I don't recall any electrical control for this valve.  Rather, 
high-vacuum conditions -- which occurred when the throttle was closed at 
speed, -- would cause the valve to open, diluting the incoming mixture to 
avoid an over-rich condition in the exhaust, which could literally blow the 
muffler apart.

It was 1972 when I removed the emission control (Nissan Air Injection 
System) from my 1969 U20 before I put it into my 1966 1600.  I do not recall 
any electrical connections on the anti-backfire valve.  I also do not recall 
any other "bypass" valve in the system, but mine was vintage 1969, and the 
'70s may have had a different design.  I still have the complete 1969 NAIS 
system -- been in a box since 1972.

Gary

----- Original Message ----- 
From: "John F Sandhoff" <sandhoff at csus.edu>
To: "peter harrison" <granvillecomputing at hotmail.com>
Cc: <datsun-roadsters at autox.team.net>
Sent: Monday, November 23, 2009 11:23 AM
Subject: Re: [Roadsters] 1970 Schematic


>> Looking at the wiring diagram and on the bottom under the alternator 
>> there are
>> two boxes
>>
>> 1 - a) trans switch, b) clutch switch c) bypass valve
>
> Smog control. On the '70s only there's an air valve on the intake
> manifold ("bypass valve"). I forget exact details, but depending on
> what gear you're in and what you're doing with the clutch, as I recall
> it leans out the mixture.
>
> -- John
>     John F Sandhoff   sandhoff at csus.edu   Sacramento, CA
> ________________________________________
> Support Team.Net  http://www.team.net/donate.html
>
> You are subscribed as aultgc at att.net
>
> Datsun-roadsters mailing list
>
> http://www.team.net/archive
>
> http://autox.team.net/mailman/listinfo/datsun-roadsters