When their is no vacuum to the regulator that's is when the engine is normally at WOT. At WOT the engine is using more gas so the DME commands the injector to stay open longer. For a cold engine a rich mixture is essential for it to start and run. For a warm or hot engine (Yes even after 20 minutes the engine is still hot) less gas is require to start the engine so the injector should be closed for a longer period of time.

It starts right up after you leave the key on for a few second because the fuel pump is switch off by the DME if the engine hasn't started within that period. It will keep the fuel pump off until the engine starts.

You can try this the next time you try a warm start. Before starting the car, push the accelerator pedal all the way to the floor and hold it there. This will tell the DME that the engine is flooded and to not start the fuel pump. Start the engine, does it start right away?

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2006 Infiniti G35
2001 BMW 3.0I E53 X5 Build date 08/2000 SOLD
Lotus Europa 1970 Destroyed by fire
Lotus Europa 1970 S2 Renault Powered
Lotus Type 52 1970 Twincam Webers Powered
PORSCHE 911 Targa 1982 The Garage Queen
Audi Avant donated to Kars for Kids
BMW 525IT Sold
Audi 4000CS Quattro Sold
Jensen Healey Lotus Powered Sold
Opel 1900 Sold
Triumph Spitfire 1971 Sold
Triumph Spitfire 1968 Sold
Plymouth "Cuda" 340 Six pack SOLD