Triumph Repair/Gulp valve
Hi Howard. I have a triumph spitfire 1979. I read that if back-fire takes place, is bacause a faulty EGR valve or Gulp valve. How is the original gulp valve, and how it is installed and how is the pipes routing ? thank you
The gulp valve or diverter valve as it is sometimes called diverts air form the air pump while the engine is decelerating to help prevent back fires on deceleration. To operate, it must have a vacuum hose connected to the small vacuum port. The vacuum must be straight manifold vacuum.
The EGR (Exhaust Gas Recirculating) valve routs exhaust gas into the intake when the throttle is slightly open but closes at idle and at full throttle. The method it does this is that the vacuum control port is close to the edge of the throttle plate (on the Stromberg carburetors that port is usually on top between the mounting flange and the top diaphragm mount.) At idle there is no vacuum and only when the throttle is sopened does any vacuum open the EGR valve. At full throttle the amount of vacuum is so low in the manifold that the EGR valve closes. The vacuum line may have a small metal trap in the line to prevent raw fuel from entering the EGR valve.